Research - Exercise / Physical Activity
Ashwagandha Improves Muscle Strength and Recovery in Men Performing Resistance Training
Wankhede S, Langade D, Joshi K, Sinha SR, Bhattacharyya S. Examining the effect of Withania somniferasupplementation on muscle strength and recovery: a randomized controlled trial. J Int Soc Sports Nutr. November 25, 2015;12:43. doi: 10.1186/s12970-015-0104-9.
Ashwagandha (Withania somnifera, Solanaceae) root is an adaptogen, helping the body adapt to stress. Although it has been shown to have a wide range of beneficial effects, studies of ashwagandha as an ergogenic aid are lacking. The authors hypothesize that ashwagandha supplementation may enhance the physiological adaptation of the body in response to the stress of weight resistance training. Hence, the purpose of this 8-week, randomized, double-blind, placebo-controlled study was to evaluate the effects of ashwagandha on healthy men performing resistance training.
Healthy men (n = 57, aged 18-50 years) with little experience in resistance training were recruited at a gymnasium in Kolkata, India. Subjects were excluded if they were taking any medication or steroids to enhance physical performance; had weight loss of > 5 kg in the previous 3 months; had history of drug abuse, smoking > 10 cigarettes day, or consuming > 14 grams of alcohol/day; were hypersensitive to ashwagandha; had orthopedic injury or surgery within the previous 6 months; had participated in other clinical studies during the previous 3 months; or had any other condition which the investigators judged problematic. Subjects were instructed not to take anti-inflammatory agents, drink alcohol, or smoke tobacco (Nicotiana tabacum, Solanaceae) during the study.
Subjects received either placebo (starch) or 600 mg/day ashwagandha root extract (KSM-66®; Ixoreal Biomed; Los Angeles, California) for 8 weeks. The extract was produced using a water-based process and was standardized to contain 5% withanolides. During the 8-week study period, subjects participated in a structured resistance training program based on the publications of the National Strength and Conditioning Association (NSCA); Colorado Springs, Colorado. Subjects trained every other day (3x/week), exercising the major muscle groups in both the upper body and lower body. During the first 2-week acclimatization phase, each exercise set consisted of 15 repetitions at a lower load to allow the subject's body and neurological system to adjust to the training. The subsequent 6 weeks of training consisted of varying numbers of higher-load repetitions.
The primary endpoints were upper body and lower body muscle strength. The secondary endpoints were muscle size, muscle recovery, serum testosterone level, and body fat percentage. Muscle size was measured at the arm, chest, and upper thigh. Creatine kinase levels were assessed as a measure of muscle recovery (reduction in exercise-induced muscle damage over time). Assessments were made 1-2 days after the first day of training, and 2 days after the end of the 8-week training period.
As expected, the resistance training resulted in improvements in all of the measured parameters in both groups. However, the ashwagandha group had a significantly greater increase in upper body (P = 0.001) and lower body (P = 0.04) strength compared with placebo; it also had significantly better muscle recovery (P = 0.03). Compared with placebo, the ashwagandha group had a significantly greater increase in the muscle size of the arm (P = 0.01) and chest (P < 0.001), but there was no significant difference in the size of the upper thigh. The ashwagandha group had a significantly greater increase in serum testosterone (P = 0.004) and a significantly greater decrease in body fat percentage (P = 0.03), compared to placebo. Ashwagandha was well tolerated, and there were no serious adverse effects.
The focal question of this study was whether ashwagandha supplementation would increase the adaptations to resistance training. At a P value of 0.05, the adaptations as measured by muscle strength, muscle size, testosterone level, and body fat percentage were found to be significantly greater with ashwagandha compared to placebo. The authors conclude that "ashwagandha supplementation is associated with significant increases in muscle mass and strength and suggests that ashwagandha supplementation may be useful in conjunction with a resistance training program." Acknowledged limitations were that only untrained subjects ≤ 50 years were included, the relatively small sample size, and short duration of the study. The authors recommend further studies evaluate the potential benefit of ashwagandha over longer periods of time and for different populations, including females and older adults of both genders.
—Heather S. Oliff, PhD
Source : American Botanical Council - Herbclip
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Dietary nitrate improves sprint performance and cognitive function during prolonged intermittent exercise
- Christopher Thompson
- , Lee J. Wylie
- , Jonathan Fulford
- , James Kelly
- , Matthew I. Black
- ,Sinead T. J. McDonagh
- , Asker E. Jeukendrup
- , Anni Vanhatalo
- , Andrew M. Jones
It is possible that dietary nitrate (NO3 −) supplementation may improve both physical and cognitive performance via its influence on blood flow and cellular energetics.
To investigate the effects of dietary NO3 − supplementation on exercise performance and cognitive function during a prolonged intermittent sprint test (IST) protocol, which was designed to reflect typical work patterns during team sports.
In a double-blind randomised crossover study, 16 male team-sport players received NO3 −-rich (BR; 140 mL day−1; 12.8 mmol of NO3 −), and NO3 −-depleted (PL; 140 mL day−1; 0.08 mmol NO3 −) beetroot juice for 7 days. On day 7 of supplementation, subjects completed the IST (two 40-min “halves” of repeated 2-min blocks consisting of a 6-s “all-out” sprint, 100-s active recovery and 20 s of rest), on a cycle ergometer during which cognitive tasks were simultaneously performed.
Total work done during the sprints of the IST was greater in BR (123 ± 19 kJ) compared to PL (119 ± 17 kJ; P < 0.05). Reaction time of response to the cognitive tasks in the second half of the IST was improved in BR compared to PL (BR first half: 820 ± 96 vs. second half: 817 ± 86 ms; PL first half: 824 ± 114 vs. second half: 847 ± 118 ms; P < 0.05). There was no difference in response accuracy.
These findings suggest that dietary NO3 − enhances repeated sprint performance and may attenuate the decline in cognitive function (and specifically reaction time) that may occur during prolonged intermittent exercise.
Source : European Journal of Applied Physiology
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Beetroot juice supplementation speeds O2 uptake kinetics and improves exercise tolerance during severe-intensity exercise initiated from an elevated metabolic rate
Breese BC1, McNarry MA, Marwood S, Blackwell JR, Bailey SJ, Jones AM.
AbstractRecent research has suggested that dietary nitrate (NO3(-)) supplementation might alter the physiological responses to exercise via specific effects on type II muscle. Severe-intensity exercise initiated from an elevated metabolic rate would be expected to enhance the proportional activation of higher-order (type II) muscle fibers. The purpose of this study was, therefore, to test the hypothesis that, compared with placebo (PL), NO3(-)-rich beetroot juice (BR) supplementation would speed the phase II VO2 kinetics (τ(p)) and enhance exercise tolerance during severe-intensity exercise initiated from a baseline of moderate-intensity exercise. Nine healthy, physically active subjects were assigned in a randomized, double-blind, crossover design to receive BR (140 ml/day, containing ~8 mmol of NO3(-)) and PL (140 ml/day, containing ~0.003 mmol of NO3(-)) for 6 days. On days 4, 5, and 6 of the supplementation periods, subjects completed a double-step exercise protocol that included transitions from unloaded to moderate-intensity exercise (U→M) followed immediately by moderate to severe-intensity exercise (M→S). Compared with PL, BR elevated resting plasma nitrite concentration (PL: 65 ± 32 vs. BR: 348 ± 170 nM, P < 0.01) and reduced the VO2 τ(p) in M→S (PL: 46 ± 13 vs. BR: 36 ± 10 s, P < 0.05) but not U→M (PL: 25 ± 4 vs. BR: 27 ± 6 s, P > 0.05). During M→S exercise, the faster VO2 kinetics coincided with faster near-infrared spectroscopy-derived muscle [deoxyhemoglobin] kinetics (τ; PL: 20 ± 9 vs. BR: 10 ± 3 s, P < 0.05) and a 22% greater time-to-task failure (PL: 521 ± 158 vs. BR: 635 ± 258 s, P < 0.05). Dietary supplementation with NO3(-)-rich BR juice speeds VO2 kinetics and enhances exercise tolerance during severe-intensity exercise when initiated from an elevated metabolic rate.
Source : Am J Physiol Regul Integr Comp Physiol.
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Curcumin supplementation likely attenuates delayed onset muscle soreness (DOMS)
IntroductionOral curcumin decreases inflammatory cytokines and increases muscle regeneration in mice.
PurposeTo determine effects of curcumin on muscle damage, inflammation and delayed onset muscle soreness (DOMS) in humans.
MethodSeventeen men completed a double-blind randomized-controlled crossover trial to estimate the effects of oral curcumin supplementation (2.5 g twice daily) versus placebo on single-leg jump performance and DOMS following unaccustomed heavy eccentric exercise. Curcumin or placebo was taken 2 d before to 3 d after eccentric single-leg press exercise, separated by 14-d washout. Measurements were made at baseline, and 0, 24 and 48-h post-exercise comprising: (a) limb pain (1–10 cm visual analogue scale; VAS), (b) muscle swelling, (c) single-leg jump height, and (d) serum markers of muscle damage and inflammation. Standardized magnitude-based inference was used to define outcomes.
ResultsAt 24 and 48-h post-exercise, curcumin caused moderate-large reductions in pain during single-leg squat (VAS scale −1.4 to −1.7; 90 %CL: ±1.0), gluteal stretch (−1.0 to −1.9; ±0.9), squat jump (−1.5 to −1.1; ± 1.2) and small reductions in creatine kinase activity (−22–29 %; ±21–22 %). Associated with the pain reduction was a small increase in single-leg jump performance (15 %; 90 %CL ± 12 %). Curcumin increased interleukin-6 concentrations at 0-h (31 %; ±29 %) and 48-h (32 %; ±29 %) relative to baseline, but decreased IL-6 at 24-h relative to post-exercise (−20 %; ±18 %).
ConclusionsOral curcumin likely reduces pain associated with DOMS with some evidence for enhanced recovery of muscle performance. Further study is required on mechanisms and translational effects on sport or vocational performance.
Source : EU Journal of Applied Physiology
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Exercise attenuates inflammation and limits scar thinning after myocardial infarction in mice
Sarah-Lena Puhl,1 Andreas Müller,2 Michael Wagner,1 Yvan Devaux,3 Michael Böhm,1 Daniel R. Wagner,4 and Christoph Maack1
Although exercise mediates beneficial effects in patients after myocardial infarction (MI), the underlying mechanisms as well as the question of whether an early start of exercise after MI is safe or even beneficial are incompletely resolved. The present study analyzed the effects of exercise before and reinitiated early after MI on cardiac remodeling and function. Male C57BL/6N mice were housed sedentary or with the opportunity to voluntarily exercise for 6 wk before MI induction (ligation of the left anterior descending coronary artery) or sham operation. After a 5-day exercise-free phase after MI, mice were allowed to reexercise for another 4 wk. Exercise before MI induced adaptive hypertrophy with moderate increases in heart weight, cardiomyocyte diameter, and left ventricular (LV) end-diastolic volume, but without fibrosis. In sedentary mice, MI induced eccentric LV hypertrophy with massive fibrosis but maintained systolic LV function. While in exercised mice gross LV end-diastolic volumes and systolic function did not differ from sedentary mice after MI, LV collagen content and thinning of the infarcted area were reduced. This was associated with ameliorated activation of inflammation, mediated by TNF-, IL-1, and IL-6, as well as reduced activation of matrix metalloproteinase 9. In contrast, no differences in the activation patterns of various MAPKs or adenosine receptor expressions were observed 5 wk after MI in sedentary or exercised mice. In conclusion, continuous exercise training before and with an early reonset after MI ameliorates adverse LV remodeling by attenuating inflammation, fibrosis, and scar thinning. Therefore, an early reonset of exercise after MI can be encouraged.
Source : Am J Physiol Heart Circ Physiol.
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Effectiveness of two year balance training programme on prevention of fall induced injuries in at risk women aged 75-85 living in community: Ossébo randomised controlled trial
Objective To assess the effectiveness of a two year exercise programme of progressive balance retraining in reducing injurious falls among women aged 75-85 at increased risk of falls and injuries and living in the community.
Design Pragmatic multicentre, two arm, parallel group, randomised controlled trial.
Setting 20 study sites in 16 medium to large cities throughout France.
Participants 706 women aged 75-85, living in their own home, and with diminished balance and gait capacities, randomly allocated to the experimental intervention group (exercise programme, n=352) or the control group (no intervention, n=354).
Intervention Weekly supervised group sessions of progressive balance training offered in community based premises for two years, supplemented by individually prescribed home exercises.
Outcome measures A geriatrician blinded to group assignment classified falls into one of three categories (no consequence, moderate, severe) based on physical damage and medical care. The primary outcome was the rate of injurious falls (moderate and severe). The two groups were compared for rates of injurious falls with a “shared frailty” model. Other outcomes included the rates of all falls, physical functional capacities (balance and motor function test results), fear of falling (FES-I), physical activity level, and perceived health related quality of life (SF-36). Analysis was by intention to treat.
Results There were 305 injurious falls in the intervention group and 397 in the control group (hazard ratio 0.81, 95% confidence interval 0.67 to 0.99). The difference in severe injuries (68 in intervention group v 87 in control group) was of the same order of magnitude (0.83, 0.60 to 1.16). At two years, women in the intervention group performed significantly better on all physical tests and had significantly better perception of their overall physical function than women in the control group. Among women who started the intervention (n=294), the median number of group sessions attended was 53 (interquartile range 16-71). Five injurious falls related to the intervention were recorded.
Conclusion A two year progressive balance retraining programme combining weekly group and individual sessions was effective in reducing injurious falls and in improving measured and perceived physical function in women aged 75-85 at risk of falling.
Source : BMJ
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Alleviating exercise induced muscular stress using neat and processed bee pollen: oxidative markers, mitochondrial enzymes and myostatin expression in rats
- Sameer Ketkara,
- Atul Rathorea,
- Amit Kandharea,
- Sathiyanarayanan Lohidasana,
- Subhash Bodhankara,
- Anant Paradkarb, , ,
- Kakasaheb Mahadika,
Honeybee collected pollen, traditionally known rich source of antioxidant principles is claimed to be useful food for sportsmen and athletes, however very few scientific evidences are available for same. Current study was designed to investigate influence of monofloral Indian mustard bee pollen (MIMBP) and processed monofloral Indian mustard bee pollen (PMIMBP) supplementation on chronic swimming exercise induced oxidative stress implications in gastrocnemius muscle of Wistar rats.
MIMBP was processed with edible lipid-surfactant mixture (Captex355:Tween80) to increase the extraction of polyphenols and flavonoid aglycones as analyzed by UV spectroscopy and HPLC-PDA. Wistar rats in different groups were fed with MIMBP or PMIMBP supplements at a dose of 100, 200 and 300 mg/kg individually when subjected to chronic swimming exercise for 4 weeks (5 days/week). Various biochemical (SOD, GSH, MDA, NO, total protein content), mitochondrial (complex I, II, III, IV enzyme activity) and molecular (myostatin mRNA expression) parameters were monitored in gastrocnemius muscle of all the groups.
Administration of both MIMBP (300 mg/kg) and PMIMBP (100,200,300 mg/kg) exerted antioxidant effect by significantly improving SOD, GSH, MDA, NO and total protein levels. Further MIMBP (300 mg/kg) and PMIMBP (200,300 mg/kg) significantly improved the impaired mitochondrial complex I, II, III, IV enzyme activity. Significant down-regulation of myostatin mRNA expression by MIMBP (300 mg/kg) and PMIMBP (200,300 mg/kg) indicates their muscle protectant role in oxidative stress conditions.
The study establishes antioxidant, mitochondrial up-regulatory and myostatin inhibitory effect of both MIMBP and PMIMBP in exercise induced oxidative stress conditions, suggesting their usefulness in effective management of exercise induced muscular stress. Further, processing of MIMBP with edible lipid-surfactant mixture was found to improve the therapeutic efficiency of pollen.
Source : Integrative Medicine Research
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Can Exercise Help People with Parkinson’s Disease?
Exercise may help people with Parkinson’s disease improve their balance, ability to move around and quality of life, even if it does not reduce their risk of falling, according to a new study published in the December 31, 2014, online issue of Neurology®, the medical journal of the American Academy of Neurology.
For the study, 231 people with Parkinson’s disease either received their usual care or took part in an exercise program of 40 to 60 minutes of balance and leg strengthening exercises three times a week for six months. This minimally-supervised exercise program was prescribed and monitored by a physical therapist with participants performing most of the exercise at home. On average, 13 percent of the exercise sessions were supervised by a physical therapist.
Falling is a common problem for people with Parkinson’s, with 60 percent falling each year and two-thirds of those falling repeatedly. “The resulting injuries, pain, limitations of activity and fear of falling again can really affect people’s health and well-being,” said study author Colleen G. Canning, PhD, of the University of Sydney in Australia.
Compared to those in the control group, the number of falls by participants who exercised was reduced in those with less severe Parkinson’s disease, but not in those with more severe disease. For those with less severe disease a 70 percent reduction in falls was reported in those who exercised compared to those who did not.
“These results suggest that minimally supervised exercise programs aimed at reducing falls in people with Parkinson’s should be started early in the disease process,” Canning said.
Overall, those who took part in the exercise program performed better on tests of ability to move around and balance, had a lower fear of falls and reported better overall mood and quality of life.
Source : American Academy of Neurology
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Low vitamin C values are linked with decreased physical performance and increased oxidative stress: reversal by vitamin C supplementation
- Vassilis Paschalis,
- Anastasios A. Theodorou,
- Antonios Kyparos,
- Konstantina Dipla,
- Andreas Zafeiridis,
- George Panayiotou,
- Ioannis S. Vrabas,
- Michalis G. Nikolaidis
It has been suggested that part of the failure of antioxidant supplementation to reduce oxidative stress and promote health is that it has been administered in humans with normal levels of antioxidants.
To test this hypothesis, we screened 100 males for vitamin C baseline values in blood. Subsequently, the 10 individuals with the lowest and the 10 with the highest vitamin C values were assigned in two groups. Using a placebo-controlled crossover design, the 20 selected subjects performed aerobic exercise to exhaustion (oxidant stimulus) before and after vitamin C supplementation for 30 days.
The low vitamin C group had lower VO2max values than the high vitamin C group. Vitamin C supplementation in this group marginally increased VO2max. Baseline concentration of F2-isoprostanes and protein carbonyls was higher in the low vitamin C group compared to the high vitamin C group. Vitamin C supplementation decreased the baseline concentration of F2-isoprostanes and protein carbonyls in both groups, yet the decrease was greater in the low vitamin C group. Before vitamin C supplementation, F2-isoprostanes and protein carbonyls were increased to a greater extent after exercise in the high vitamin C group compared to the low vitamin C group. Interestingly, after vitamin C supplementation, this difference was narrowed.
We show for the first time that low vitamin C concentration is linked with decreased physical performance and increased oxidative stress and that vitamin C supplementation decreases oxidative stress and might increase exercise performance only in those with low initial concentration of vitamin C.
Source : EU Journal of Nutrition
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For Survivors of Colorectal Cancer, More Exercise, Less TV May Lower Risk of Death
“Turn off the TV and go outside and play” is an admonishment heard by many children—sage advice that seems to benefit adults as well. According to a new article in the Journal of Clinical Oncology (JCO), the simple recipe of “more exercise, less TV” might be particularly beneficial for survivors of colorectal cancer (CRC).
The study, “Pre- and Post-Diagnosis Physical Activity, Television Viewing, and Mortality Among Colorectal Cancer Patients in the NIH-AARP Diet and Health Study,” published online, ahead of print, December 8, 2014, asked how time devoted to exercising and watching TV— both before and after diagnosis— affected the risk of dying among survivors of colorectal cancer. To answer this question, the researchers used data from the NIH-AARP Diet and Health Study, which provided pre-diagnosis information on 3,797 survivors of CRC and post-diagnosis information on 1,759 survivors.
In summing up the findings of the study, first author Hannah Arem, PhD, MHS, of the National Cancer Institute, said, “The takeaway message from our study is that the colorectal cancer survivors who both watched less TV and did more exercise had the lowest mortality compared to those who watched more TV and did less exercise.”
More exercise associated with lower mortality risk
The study found that survivors of CRC who exercised seven hours or more per week before their diagnosis had a 20% lower risk of dying of any cause compared to survivors who did not exercise at all. Those who exercised seven hours or more per week after their diagnosis had a 31% lower risk of dying of any cause compared to survivors who did not exercise—a similar benefit was observed among survivors who exercised as little as four hours per week both before and after diagnosis. Exercising after diagnosis was associated with a reduced risk of death independent of whether or not the survivor exercised before diagnosis. On average, survivors’ reports on exercise were given four years after diagnosis.
Four to five hours of TV watching per day associated with greater mortality risk
The study also reported that survivors of CRC who watched more than five hours of TV per day before their diagnosis had a 22% increased risk of dying of any cause, compared to survivors who watched less than two hours per day. As far as TV watching after diagnosis, survivors who watched more than four hours of TV per day had a 25% increased mortality risk compared to survivors who watched less than two hours per day; however, this post-diagnosis difference was not statistically significant.
Colorectal Cancer Survivorship: an important public health issue
Only one previous study examined the association between sedentary activity and survivorship among survivors of CRC, and this current study is the first to look specifically at TV watching. Dr. Arem said that one of the reasons the researchers chose to focus on TV watching is that it is a behavior that can be modified with relative ease.
“TV watching is the most prevalent leisure time behavior, and it is an area where individuals can intervene,” said Dr. Arem. “It’s a lot harder to ask someone to change how they sit at work or which transportation mode they use. Asking people to reduce time in front of a TV is a public health message that can be put into action.”
According to Dr. Arem, identifying behaviors that can reduce the mortality risk among survivors of CRC is an important public health issue since the population of survivors numbers one million in the United States, and is growing.
“This is a population that deserves to have more research on their specific needs,” said Dr. Arem.
And as this new research in JCO suggests, one of those specific needs may be to leave the couch and take a walk outside.
“The findings in this study add another piece of evidence that for the more than one million survivors of colorectal cancer, even moderate exercise, such as walking four hours per week and keeping TV watching to two hours a day, might improve survival in this population.”
Source ASCO Connections
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Exercise boosts tumor-fighting ability of chemotherapy
Combining exercise with chemotherapy shrunk tumors more than chemotherapy alone, according to research performed in a mouse model of melanoma.
Exercise has long been recommended to cancer patients for its physical and psychological benefits. This research team was particularly interested in testing whether exercise could protect against the negative cardiac-related side effects of the common cancer drug doxorubicin. Though effective at treating a variety of types of cancer, doxorubicin is known to damage heart cells, which could lead to heart failure in the long term.
The study was led by Joseph Libonati, PhD, FAHA, an associate professor in the School of Nursing and director of the Laboratory of Innovative and Translational Nursing Research at the University of Pennsylvania in Philadelphia. This research study was published in the American Journal of Physiology (2014; doi:10.1152/ajpregu.00082.2014).
“The immediate concern for these patients is, of course, the cancer, and they'll do whatever it takes to get rid of it,” Libonati said. “But then when you get over that hump you have to deal with the long-term elevated risk of cardiovascular disease.”
Previous studies had shown that an exercise regime prior to receiving chemotherapy could protect heart cells from the toxic effects of doxorubicin, but few had looked to see whether an exercise regimen during chemotherapy could be beneficial.
To do so, Libonati's team set up an experiment with four groups of mice. All were given an injection of melanoma cells in the scruffs of their neck. During the next 2 weeks, two of the groups received doxorubicin in two doses while the other two groups received placebo. The mice in one treated group and one placebo group were put on exercise regimens, walking 45 minutes 5 days a week on mouse-sized treadmills, while the rest of the mice remained sedentary.
After the 2-week trial, the researchers examined the animals' hearts using echocardiogram and tissue analysis. As expected, doxorubicin was found to reduce the heart's function and size and increased fibrosis, which is a damaging thickening of tissue. Mice that exercised were not protected from this damage.
“We looked, and the exercise didn't do anything to the heart. It didn't worsen it, it didn't help it,” Libonati said. “But the tumor data—I find them actually amazing.”
The amazing result was that the mice that both received chemotherapy and exercised had significantly smaller tumors after 2 weeks than mice that only received doxorubicin. This could be partly because exercise increases blood flow to the tumor, bringing with it more of the drug in the bloodstream.
“If exercise helps in this way, you could potentially use a smaller dose of the drug and get fewer side effects,” Libonati said.
“People don't take a drug and then sit down all day,” Libonati said. “Something as simple as moving affects how drugs are metabolized. We're only just beginning to understand the complexities.”
Source : Oncology Nurse Advisor
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Protective Effect of Curcuma Longa Rhizomes against Physical Stress-induced Perturbations in Rats
M. Bhanumathy, H. N. Shivaprasad, L. V. G. Nargund
Curcuma longa (Turmeric) is a bright yellow ancient spice native to Asian countries. It has been used as traditional remedy dating back to 600 BC. Turmeric is well known for its applications as a cosmetic, condiment and flavoring agent. The present study was an attempt to explore the protective effect of Curcuma longa rhizomes against physical stress-induced perturbations in rats. Animals were pre-treated with extracts of C. longa rhizomes (crystallized ethylacetate extract; and byproduct-oleoresin) at doses of 200 and 400 mg/kg for 21 days. The effect on swimming endurance followed by post-swimming muscle co-ordination and spontaneous motor activity was evaluated. Estimation of brain monoamine levels in rats and HPLC analysis were carried out. Pre-treated rats with C. longa extracts showed dose dependant significant enhancement in swimming endurance time, increased the duration (sec) of stay on rota-rod apparatus and increased the count (actophotometer score) in spontaneous motor activity. In addition, the pre-treated rats were found to possess normalizing activity against physical stress induced changes in norepinephrine, dopamine and serotonin. Curcuminoids was identified by HPLC analysis and it was one of the active principles responsible for the adaptogenic activity. Extracts of C. longa rhizomes exhibited adaptogenic activity against physical stress model followed by post-swimming muscle co-ordination and spontaneous motor activity, which could be due to the presence of curcuminoids content. In conclusion, the results of the present investigation emphasized the protective effect of C. longa rhizomes against physical stress-induced perturbations in rats.
Source : Journal of Natural Remedies
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Dark Chocolate Intake Improves Walking Distance and Walking Time in Patients with Peripheral Artery Disease
Loffredo L, Perri L, Catasca E, et al. Dark chocolate acutely improves walking autonomy in patients with peripheral artery disease. J Am Heart Assoc. July 2014;3(4). pii: e001072. doi: 10.1161/JAHA.114.001072.
More than a fifth of adults older than 70 years are affected by peripheral arterial disease (PAD) in Western countries.1 A major symptom of the disease is intermittent claudication (IC), pain caused by impaired blood flow to the limbs during physical exercise. Reduced blood flow in patients with PAD is the result of endothelial dysfunction, reduced glucose oxidation, accumulation of toxic metabolites, impaired nitric oxide (NO) generation, and/or oxidative stress. In an earlier study,2 oxidative stress resulted in impaired walking distance autonomy (WDA), while inhibiting oxidative stress led to improved maximal walking distance (MWD). Polyphenol-rich cocoa (Theobroma cacao) has been associated with artery dilatation by reducing oxidative stress and increasing NO generation.3,4 In particular, dark chocolate enhances artery dilatation by lowering the activation of NOX2, a subunit of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, which has been shown to exert vasoconstrictor activity in both animals and humans. These authors conducted an interventional, crossover, single-blinded study to measure the acute effect of dark chocolate on WDA, artery dilatation, and NOX2-mediated oxidative stress in patients affected by moderate-to-severe PAD.
Specifically, the trial investigated the acute effect of 40 g chocolate (dark vs. milk) on MWD, maximal walking time (MWT), ankle brachial index (ABI) at rest and postexercise, flow-mediated dilatation (FMD), oxidative stress, and NO generation. Oxidative stress was assessed through blood levels of NOX-2 derivative peptide (sNOX2-dp; a marker of NOX2 activation) and isoprostanes. Serum levels of nitrite-nitrate (NOx) were used to evaluate NO generation.
The study, conducted between January 2012 and September 2013, included 20 patients with PAD with IC. At baseline, all patients underwent a full medical history and physical examination and answered a questionnaire about their fruit and vegetable intake. They were randomly assigned to receive either 40 g dark chocolate (≥85% cocoa) or milk chocolate (≤35% cocoa) in a crossover design, with at least 1 week separating the 2 intervention phases. The modified Folin-Ciocalteu colorimetric method used to determine the polyphenol content of the chocolate revealed a significantly higher total and single polyphenol content in the dark compared with the milk chocolate (P<0.001).
On study visit days, fasting blood samples were collected, followed by the first ABI and FMD at rest. The patients then completed the first treadmill test, after which MWD and MWT were measured and postexercise ABI was performed. The patients consumed 40 g of dark or milk chocolate. Two hours later, blood samples were again collected to analyze oxidative stress markers and epicatechin levels, and a second ABI and FMD evaluation was conducted. After 20 minutes, each patient completed a second treadmill test to determine MWD and MWT, followed by another postexercise ABI.
Compared with baseline, no difference was observed 2 hours after milk chocolate consumption in serum epicatechin, its metabolite EC-3-O-methylether, or epigallocatechin-3-gallate (EGCG) levels; however, the levels of serum catechin increased significantly. Two hours after dark chocolate intake, serum levels of epicatechin and its metabolite EC-3-O-methylether, catechin, and EGCG increased compared with baseline values.
Compared with baseline, MWD and MWT increased after dark chocolate intake (P<0.001 for both) but not after milk chocolate intake. This is a novel finding, according to the authors, noting that it supports the hypothesis that polyphenol content may be responsible for this effect, as dark chocolate is richer in polyphenols than milk chocolate.5
In a within-group analysis, no significant effect on ABI at rest or after exercise was observed after dark or milk chocolate intake. The analysis of variance performed on the study data revealed a significant difference for treatments in FMD (P=0.003); sNOX2-dp release (P=0.04); serum 8-iso-prostaglandin F2α-III, an indicator of lipid peroxidation (P=0.018); MWD (P=0.01); MWT (P=0.006); and postexercise ABI (P=0.04).
Pairwise comparisons showed that sNOX2-dp (P<0.001) and serum isoprostanes (P=0.01) significantly decreased after dark chocolate consumption but not after milk chocolate intake. FMD (P<0.001) and NOx(P=0.001) increased after dark chocolate intake, but no changes were observed after milk chocolate intake.
Performing a multiple linear regression analysis using a forward selection, the authors report "that Δ of MWD was independently associated with Δ of MWT (P<0.001) and Δ of NOx (P=0.018)."
The authors conducted an accompanying in vitro study in which human umbilical vein endothelial cells (HUVECs) were cultured to analyze the effect of scalar doses of single polyphenols such as epicatechin, catechin, or EGCG or a mixture of those on HUVEC activation. They found that HUVECs incubated with a mixture of polyphenols significantly increased NO (P<0.001). Significant decreases were seen in levels of E-selectin (P<0.001) and soluble vascular adhesion molecule-1 (P<0.001) (both associated with cardiovascular disease risk).
The vasodilating effect of dark chocolate could be due to the antioxidant effect of its polyphenols, which has been documented in humans through reduction of oxidative stress markers and an increase in its plasma antioxidant property. In this study, the patients who consumed dark chocolate experienced short-term changes in oxidative stress elicited by reduced serum isoprotanes, reduced NOX2 activity, and enhanced generation of NO. "These data may lead to speculation that the enhanced NO generation could be responsible for artery dilatation and eventually improve WDA," write the authors.
Referring to the study's limitations, the authors suggest that although the study is useful in understanding the mechanism of disease related to IC, the results are not transferable to clinical practice because of the small sample size and study design (single-blinded with no placebo group). Also, they say, only indirect evidence suggests that vasodilation is the mechanism behind the increase in walking autonomy; a direct analysis of peripheral circulation was not done.
"The results of this study suggest that short-term administration of dark chocolate improves walking autonomy with a mechanism involving its high content of polyphenols and perhaps mediated by an oxidative stress mechanism, which ultimately leads to enhanced NO generation." A longer duration of dark chocolate intake should be studied to assess whether it could be used to treat IC in patients with PAD.
Source : American Botanical Council
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A socio-ecological approach promoting physical activity and limiting sedentary behavior in adolescence showed weight benefits maintained 2.5 years after intervention cessation
Open C Simon1,2,3, N Kellou1, J Dugas1, C Platat4, N Copin2,3, B Schweitzer5, F Hausser6, A Bergouignan7, E Lefai1 and S Blanc8
Background:Obesity in youth remains a major public health issue. Yet no effective long-term preventive strategy exists. We previously showed that a school-based socio-ecological approach targeting behavior and social/environmental influences on physical activity (PA) prevented 4-year excessive weight gain in 12-year olds. In this study, we investigated if this efficacy persists 30 months after intervention cessation.Methods and Findings:The program targeted students, family, school and the living environment to promote/support PA and prevent sedentary behavior (SB). A total of 732 students from eight randomized middle schools completed the 4-year trial. At the 30-month post-trial follow-up, body mass index (BMI), fat mass index (FMI), leisure PA (LPA), home/school/workplace active commuting, TV/video time (TVT), and attitudes toward PA were measured in 531 adolescents. The beneficial effects of the intervention on the excess BMI increase (+0.01 vs +0.34 kg m−2 in the intervention and control groups, respectively) and on the overweight incidence in initially non-overweight students (4.3% vs 8.6%; odds ratio=0.48 (95% confidence interval: 0.23–1.01)) were maintained at the post-trial follow-up. LPA was not maintained at the level achieved during the trial. However, we still observed a prevention of the age-related decrease of the adolescents’ percentage reporting regular LPA (−14.4% vs −26.5%) and a higher intention to exercise in the intervention group. The intervention promoted lower TVT (−14.0 vs +13.6 min per day) and higher active commuting changes (+11.7% vs −4.8%). Trends in higher BMI reduction in students with high initial TVT and in the least wealthy group were noted. TVT changes throughout the follow-up predicted excess BMI and FMI changes.Conclusions:Long-term multilevel approach targeting PA and SB prevents excessive weight gain up to 30 months after intervention cessation. The efficacy may be higher in the most sedentary and least wealthy adolescents. Healthy PA-related behavior inducing long-lasting weight effects can be promoted in youth providing that an ecological approach is introduced in the prevention strategy.
Source International Journal of Obesity
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PHYSICAL ACTIVITY, OBESITY, AND BLADDER CANCER MORTALITY
Michael Liss, Martha White, Loki Natarajan, J. Kellogg Parsons
Introduction and Objectives
Physical activity and obesity are modifiable lifestyle factors that are potential therapeutic targets for bladder cancer prevention and control. However, there are limited data on physical activity, obesity, and bladder cancer mortality. Further analyses of these associations may identify novel prevention and treatment strategies for bladder cancer.
The National Health Information Survey (NHIS) is an annual representative cross-sectional household interview survey. We used baseline data from 1998 through 2004 linked to mortality data reporting deaths through 2006. The primary outcome variable was bladder cancer-specific mortality. The primary exposure variables were self-reported physical activity (dichotomized as “did no exercise” versus “light, moderate or vigorous exercise in >=10 minute-bouts”) and obesity as measured by body mass index (BMI). We utilized multivariable adjusted Cox proportional hazards regression models, with delayed entry to account for age at survey interview. Analyses were adjusted for the complex NHIS multistage sampling methodology using survey weights.
Complete data were available on 222163 participants, of whom 96715 (48%) were men and 146014 (73%) non-Hispanic Whites, and among whom we identified 83 bladder cancer-specific deaths. There were no associations of ethnicity (p=0.43) or gender (p=0.14) with bladder cancer mortality. In multivariate analyses, individuals who reported “any physical activity” were 53% less likely [adjusted hazards ratio (HRadj) 0.53; 95% CI 0.29 to 0.96; p-value = 0.038] to die of bladder cancer than non-exercisers. There were no significant differences in bladder cancer mortality for overweight (BMI 25.0 to 29.9 kg/m2, HRadj 1.06, 95% CI 0.55 to 2.04, p-value = 0.87) or obese (BMI >= 30 kg/m2, HRadj 0.61, 95% CI 0.33 to 1.12, p-value = 0.11) individuals compared to those of normal weight (BMI < 25 kg/m2). Compared to never smokers, former smokers were nearly three times as likely (HRadj 2.95, 95% CI 1.50 to 5.79; p-value<0.001) and current smokers over 4 times as likely (HRadj 4.24, 95% CI 1.86 to 9.65, p-value<0.001) to die of bladder cancer.
Physical activity decreases the risk of bladder cancer mortality. These studies suggest that exercise interventions may potentially prevent bladder cancer death.
Source : Journal Urology
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Effect of Aerobic Training on Heart Rate Recovery in Patients with Established Heart Disease; a Systematic Review
Johan A. Snoek mail, Sietske van Berkel, Nico van Meeteren, Frank J. G. Backx, Hein A. M. Daanen Abstract
Background Although a delayed decrease in heart rate during the first minute after graded exercise has been identified as a powerful predictor of overall mortality in cardiac patients, the potential to influence this risk factor by aerobic training remains to be proven.
Objective The aim was to study the relationship between aerobic training and Heart Rate Recovery (HRR) in patients with established heart disease.
Methods (Quasi) randomized clinical trials on aerobic exercise training in adults with established heart disease were identified through electronic database and reference screening. Two reviewers extracted data and assessed the risk of bias and therapeutic validity. Methodological validity was evaluated using an adapted version of the Cochrane Collaboration’s tool for assessing risk of bias and the therapeutic validity of the interventions was assessed with a nine-itemed, expert-based rating scale (CONTENT). Scores range from 0 to 9 (score ≥ 6 reflecting therapeutic validity).
Results Of the 384 articles retrieved, 8 studies (449 patients) were included. Three of the included studies demonstrated adequate therapeutic validity and five demonstrated low risk of bias. Two studies showed both adequate therapeutic validity and a low risk of bias. For cardiac patients aerobic exercise training was associated with more improvement in HRR compared to usual care.
Conclusion The present systematic review shows a level 1A evidence that aerobic training increases HRR in patients with established heart disease.
Source : PLOS One
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Increase in ADHD Runs Parallel With Decrease in Physical Activity
Recent coverage drawing attention to the likely over-treatment of Attention Deficit Hyperactivity Disorder (ADHD) in the United States is very concerning. Data from the Centers for Disease Control and Prevention (CDC) show the diagnosis being made in 11 percent of youth by the time they finish high school, which amounts to a near six-fold increase since 1990. There is much to question about the stark rise in this largely-subjective diagnosis, particularly given the medications used to treat ADHD carry significant side-effects for patients (e.g., insomnia, appetite loss, hallucinations) and come at a hefty financial cost to society.
Experts suggest far more children are taking meds for ADHD than really need to. While severe cases of ADHD require medication, the estimated prevalence of these cases is considerably less than the number being treated today. The majority of reporting on the over-treatment of ADHD focuses on the pharmaceutical industry's comprehensive sales and marketing toolkit, which has no doubt played a large role in the rise of the diagnosis. Makers of drugs for ADHD have strategically targeted parents and teachers for the past two decades, selling their drugs as quick fixes for hyperactive kids that are "safer than aspirin," a questionable assertion at best.
Yet there may be an additional force underlying the surge in ADHD and one that is rarely mentioned if at all. America has seen an extensive reduction in physical activity, a trend that has run in lock-step with the rise of ADHD.
Kids have lots of energy and are losing opportunities to expel it naturally. According to the CDC, less than 30 percent of adolescents meet the guidelines for daily physical activity. The reasons for this are many, ranging from neighborhood safety (i.e., crime and vehicular traffic), to urban density (and subsequent reductions in green space), to the cannibalization of what was once active time with screen-based entertainment. When taken together, the vast majority of America's youth are not moving much at all. Perhaps all of this bottled up energy is being manifested as unnatural hyperactivity, when the most unnatural part of the situation is the sedentary behavior of kids.
One of the few places youth can get protected and regular physical activity is in school, yet school districts across the country are cutting back on recess, gym classes, and after school sports programs. The most common rationale for this is that dwindling resources need to be spent on core topics (e.g., math and science) to prepare America's youth for a competitive global economy. Using precious time and money to invest in meaningful physical activity programs is thus inefficient. This is particularly ironic given studies demonstrate that when youth are engaged in regular physical activity they show less anxiety, increased focus, and better performance in academic settings, many of the primary symptoms of ADHD (not to mention the clear benefits of physical activity in reducing obesity, which some consider the country's most significant economic threat -- far greater than a lack of mathematicians and scientists). It seems we may be missing the forest for the trees.
Physical activity may work just as well if not better than strong drugs in countering the symptoms of ADHD. Yet we live in a culture where people are conditioned to want a quick fix for everything, and with a medical system that has learned to provide it. Unfortunately, this is not always the best approach, and the case of ADHD may be the latest example. Before turning to expensive drugs rife with side-effects to treat ADHD, parents, physicians, teachers, and education policy makers should consider the role of physical activity, and promote making it a regular part of children's diets.
Source : Huffington Post
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Evaluation of the effects of supplementation with Pycnogenol® on fitness in normal subjects with the Army Physical Fitness Test and in performances of athletes in the 100-minute triathlon
Vinciguerra G., Belcaro G., Bonanni E., Cesarone M. R., Rotondi V., Ledda A., Hosoi M., Dugall M., Cacchio M., Cornelli U.
Irvine 3 International Circulation Vascular Labs & San Val. Epidemiology Department of Biomedical Sciences Chieti‑Pescara University, Pescara, Italy
Aim: The aim of this registry study was to evaluate the effects of Pycnogenol® (French pine bark extract) on improving physical fitness (PF) in normal individuals using the Army Physical Fitness Test (APFT). The study evaluated the efficacy of Pycnogenol, used as a supplement, in improving training, exercise, recovery and oxidative stress.
Methods: The study was divided into 2 parts. In PART 1 (Pycnogenol 100 mg/day), the APFT was used to assess an improvement in PF during an 8-week preparation and training program. In PART 2 (Pycnogenol 150 mg/day), the study evaluated the effects of Pycnogenol supplementation in athletes in training for a triathlon.
Results: PART 1. There was a significant improvement in both males and females in the 2-mile running time within both groups, but the group using Pycnogenol (74 subjects) performed statistically better than controls (73 subjects). The number of push-ups was improved, with Pycnogenol subjects performing better. Sit-ups also improved in the Pycnogenol group. Oxidative stress decreased with exercise in all subjects; in Pycnogenol subjects the results were significantly better. PART 2. In the Pycnogenol group 32 males (37.9; SD 4.4 years) were compliant with the training plan at 4 weeks. In controls there were 22 subjects (37.2;3.5) completing the training plans. The swimming, biking and running scores in both groups improved with training. The Pycnogenol group had more benefits in comparison with controls. The total triathlon time was 89 min 44 s in Pycnogenol subjects versus 96 min 5 s in controls. Controls improved their performing time on average 4.6 minutes in comparison with an improvement of 10.8 minutes in Pycnogenol subjects. A significant decrease in cramps and running and post-running pain was seen in the Pycnogenol group; there were no significant differences in controls. There was an important, significant post-triathlon decrease of PFR one hour after the end of the triathlon with an average of -26.7, whereas PFR in controls increased. In Pycnogenol subjects there was a lower increase on oxidative stress with a faster recovery to almost normal levels (<330 for these subjects). These variations in PFR values were interpreted as a faster metabolic recovery in subjects using Pycnogenol.
Conclusion: This study opens an interesting new application of the natural supplementation with Pycnogenol that, with proper hydration, good training and nutritional attention may improve training and performances both in normal subjects and in semi-professional athletes performing at high levels in difficult, high-stress sports such as the triathlon.
Source : The Journal of Sports Medicine and Physical Fitness
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Want a Better Work-Life Balance? Exercise, Study Finds
Researchers have found that exercise plays a role in how individuals feel they can manage their work-life balance.
"Individuals who exercised regularly were more confident they could handle the interaction of their work and home life and were less likely to be stressed at work," said Russell Clayton, assistant professor of management at Saint Leo University and lead author on the paper.
Conflict between work and home can be categorized in two ways. Work interference with family describes typical job-based pressures that can lead to interference (either time or psychologically) of family time. Family interference with work is when personal issues find a way into the workday and compete with "work time." Researchers wanted to find if exercise helped both.
Previous studies have shown that exercise helps to reduce stress. A previous study examined Tai Chi exercise programs over 12 weeks. Another study looked at high-intensity aerobic exercise. Both showed reductions of self-reported stress. What researchers didn't know is if the reduction of stress actually helped empower individuals to feel they had better work-life balance.
"The idea sounds counterintuitive. How is it that adding something else to our work day helps to alleviate stress and empower us to deal with work-family issues? We think exercise is a way to psychologically detach from work -- you're not there physically and you're not thinking about it either -- and, furthermore, it can help usfeel good about ourselves."
Researchers examined responses of 476 working adults to survey questions. Respondents were asked on a four-point scale (1 never -- 4 always) questions about exercise behavior. For example, "I exercise more than three days a week." Respondents were then asked a number of questions on a 7-point scale (strongly disagree -- strongly agree) about their confidence in handling work-family conflicts.
"Our findings suggest that employers can help employees with work-life balance by encouraging them to exercise."
Source : Newswise
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Study Shows Exercise Improves Depression in Parkinson's Patients
A new study by a movement disorder neurologist at The Ohio State University Wexner Medical Center found that depression improved among patients with Parkinson's disease who participated in a long-term group exercise program.
The findings are published in the journal Parkinsonism and Related Disorders.
Parkinson's disease is a progressive neurodegenerative disorder that affects more than 1 million Americans. Each year, about 60,000 Americans are newly diagnosed with Parkinson's disease. Parkinson's patients develop progressive disability over time, despite the best pharmacological and surgical management. Therefore, complementary approaches that can maximize functional ability and improve quality of life are important.
In this pilot study, 31 patients with Parkinson's disease were randomly assigned to an "early start group" or a "delayed start group" for a rigorous formal group exercise program that met for one hour, three days a week. The early start group exercised for a total of 48 weeks, while the delayed start group exercised only the last 24 weeks. One patient dropped out of the study.
"Our findings demonstrate that long-term group exercise programs are feasible in the Parkinson's disease population. Patients enjoyed exercising, and they stayed with the program that included cardiovascular and resistance training," said principal investigator Dr. Ariane Park, a movement disorder neurologist at the Madden Center for Parkinson's Disease and Related Disorders at Ohio State's Wexner Medical Center.
"Our study also showed that earlier participation in a group exercise program significantly improved symptoms of depression compared to the delayed start group, and this is important because often mood can be more debilitating than motor symptoms," Park said.
More than 50 percent of patients with Parkinson's disease suffer from depression, which is why it is important to help patients find new ways to cope and improve their symptoms, said Park, who also is a researcher in Ohio State's Neuroscience Program.
Researchers had also hoped to show that exercise could slow the progression of the disease, but the study did not provide strong evidence of any 'neuroprotective' effect on motor function, possibly because of the small sample size, Park said.
"We recommend exercise to all of our Parkinson's patients. Currently, there is no consensus on a standardized physical exercise regimen with regard to type, frequency and intensity. The literature supports that any routine that improves physical fitness is good for Parkinson's disease -- and that can include walking, swimming, tai chi or even dancing," Park said. "We just want patients to move on a regular basis. Not only will they move better, but they will feel better."
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Moderate Exercise Not Only Treats, but Prevents Depression
Physical activity is being increasingly recognized as an effective tool to treat depression. PhD candidate George Mammen’s review published in the October issue of the American Journal of Preventive Medicine has taken the connection one step further, finding that moderate exercise can actually prevent episodes of depression in the long term.
This is the first longitudinal review to focus exclusively on the role that exercise plays in maintaining good mental health and preventing the onset of depression later in life.
Mammen—who is supervised by Professor Guy Faulkner, a co-author of the review— analyzed over 26 years’ worth of research findings to discover that even low levels of physical activity (walking and gardening for 20-30 minutes a day) can ward off depression in people of all age groups.
Mammen’s findings come at a time when mental health experts want to expand their approach beyond treating depression with costly prescription medication. “We need a prevention strategy now more than ever,” he says. “Our health system is taxed. We need to shift focus and look for ways to fend off depression from the start.”
Mammen acknowledges that other factors influence a person’s likelihood of experiencing depression, including their genetic makeup. But he says that the scope of research he assessed demonstrates that regardless of individual predispositions, there’s a clear take-away for everyone. “It’s definitely worth taking note that if you’re currently active, you should sustain it. If you’re not physically active, you should initiate the habit. This review shows promising evidence that the impact of being active goes far beyond the physical.”
Source : Newswise
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Cardio and Weight Training Reduces Access to Health Care in Seniors
Forget apples -- lifting weights and doing cardio can also keep the doctors away, according a new study by researchers at the University of British Columbia and Vancouver Coastal Health Research Institute.
The study, published today in the online journal PLOS ONE, followed 86 women, aged 70- to 80-years-old, who were randomly assigned to participate in weight training classes, outdoor walking classes, or balance and toning classes (such as yoga and pilates) for six months. All participants have mild cognitive impairment, a well-recognized risk factor for Alzheimer's disease and dementia.
The researchers tabulated the total costs incurred by each participant in accessing a variety of health care resources.
"We found that those who participated in the cardio or weight training program incurred fewer health care resources -- such as doctor visits and lab tests -- compared to those in the balance and toning program," says Jennifer Davis, a postdoctoral fellow and lead author of the study.
The study is the latest in a series of studies that assess the efficacy of different types of training programs on cognitive performance in elderly patients. An earlier study, published in February in the Journal of Aging Research, showed aerobic and weight training also improved cognitive performance in study participants. Those on balance and toning programs did not.
"While balance and toning exercises are good elements of an overall health improvement program, you can't 'down-dog' your way to better brain health," says Teresa Liu-Ambrose, an Associate Professor in the UBC Faculty of Medicine and a member of the Brain Research Centre at UBC and VCH Research Institute. "The new study also shows that cardio and weight training are more cost-effective for the health care system."
Background: Exercise benefits for the brain
The new studies build on previous research by Prof. Liu-Ambrose, Canada Research Chair in Physical Activity, Mobility, Cognitive Neuroscience and a member of the Centre for Hip Health & Mobility, where she found that once- or twice-weekly weight training may help minimize cognitive decline and impaired mobility in seniors.
The weight training classes included weighted exercises targeting different muscle groups for a whole-body workout. The aerobic training classes were an outdoor walking program targeted to participants' age-specific target heart rate. The balance and toning training classes were representative of exercise programs commonly available in the community such as Osteofit, yoga, or Tai Chi.
Source : Science Daily
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Light Exercise Still Cuts Kidney Stone Risk
Women who exercised even minimally had a significantly lower risk of kidney stones, according to an analysis of a large cohort study. Overall, physically active women had about a 30% lower risk of kidney stones compared with women who reported no exercise. The risk reduction ranged as high as 80% in one analysis, reported Mathew Sorensen, MD, of the University of Washington in Seattle, and colleagues at the American Urological Association (AUA) meeting.
The benefit for stone disease kicked in with only modest physical activity of just about any intensity, he added.
"The intensity of exercises does not matter," Sorensen said during an AUA press briefing. "There was no difference between women who performed primarily mild, moderate, or strenuous activity. The protective effect of increased activity was similar for all exercisers."
Almost 10% of the adult population in the U.S. will develop a kidney stone at some point. Kidney stone incidence has increased 70% over the past 15 years, and women have accounted for much of the increase, he explained, adding that the increase has been attributed to the rising prevalence of weight gain, obesity, and metabolic syndrome.
The association with obesity is nothing new, he continued, as obesity has a long-established association as a risk factor for kidney stones. Obesity is thought to predispose people to stone formation by altering urinary pH and electrolytes. However, the association involves more than increased solute load resulting from excess caloric intake.
Systemic inflammation fueled by obesity and metabolic syndrome contribute to the risk of stone formation, as do impaired lipid handling and dyslipidemia. Most risk factors for cardiovascular disease also are common to nephrolithiasis.
Body mass index (BMI), a marker of an imbalance between energy intake and expenditure, also contributes to kidney stone risk. Sorensen and colleagues hypothesized that changes in energy intake and expenditure -- restricted caloric intake and increased physical activity -- might alter the risk.
Adjusting for BMI
To test the hypothesis, investigators analyzed data from the Women's Health Initiative, which enrolled 93,676 women, ages 50 to 79, from 1993 to 1998 and had a median follow-up of 8 years. Information elicited at enrollment and follow-up included self-reported history of kidney stones, a food frequency questionnaire, and physical activity converted into metabolic equivalents (METs) per week.
After excluding participants with a history of stone disease or incomplete information, the final analysis included 84,225 women, 2,392 (2.8%) of whom developed kidney stones during follow-up. To adjust for bias in self-reported energy intake, investigators made adjustments in subgroup study of 544 participants in 2004 and 2005, which corrected for bias on the basis of measurements involving an energy intake biomarker.
Energy intake was further calibrated according to age, BMI, race/ethnicity, income, and physical activity.
Investigators developed two statistical models for the analysis, one of which adjusted only for BMI and the other which adjusted for activity, energy intake, and BMI.
Sorensen and colleagues performed two exploratory analyses: type and intensity of a participant's primary form of exercise and total weekly METs and their associations with stone risk.
The participants had a mean age of 64, mean BMI of 27.1, and mean METs/week of 14.0.
"We found that 87% of the women reported some type of physical activity, so this was active group of people," Sorensen said.
In the model that adjusted only for BMI, being underweight (BMI <18.5 kg/m2) afforded modest protection against kidney stones (hazard ratio 0.79), and normal-weight women (BMI 18.5 to 24.9 kg/m2) served as the reference.
The BMI range for overweight (25 to 29.9 kg/m2) was associated with a 30% increase in the hazard for stone formation, rising to 62% for moderately obese women (BMI 30 to 34.9 kg/m2) and 81% for severely obese women (BMI ≥35 kg/m2).
As compared with women who reported no physical activity, women who reported any physical activity had a significantly lower (P<0.001) risk of kidney stones:
- 0.1 to 4.9 METs/week: HR 0.84
- 5 to 9.9: HR 0.78
- 10 to 19.9: HR 0.69
- 20 to 29.9: HR 0.70
- ≥30: HR 0.69
Sorensen and colleagues also examined the association between daily energy intake in kilocalories (kcal) and stone risk in their model that incorporated physical activity, energy intake, and BMI. Using 1,800 to 1,999 kcal as the reference, they found that the HR for kidney stones increased as follows:
- 1.04 for daily energy intake of 2,000 to 2,199 kcal
- 1.26 for 2,200 to 2,499 kcal
- 1.42 for ≥2,500 kcal
"You don't have to run a marathon to reduce the risk of kidney stones," Sorensen said. "Mild to moderate amounts of activity decreased the risk by 16% to 31%. The amount of activity is what mattered, not the intensity of exercise."
As an example, he said 10 METs/week would require 3 hours of average walking, 4 hours of light gardening, or 1 hour of moderate jogging.
Theories about how exercise might reduce stone risk tend to focus on changes in vitamin and mineral handling induced by physical activity, including reduced sodium excretion, increased fluid intake, decreased sympathetic tone, and improved bone density. Noting a strong association between cardiovascular disease and stone formation, Sorensen said reducing cardiac risk factors favorably affects stone risk, including hypertension, diabetes, obesity, and cholesterol.
The findings require validation in men and in people who have a history of stone formation, said AUA press briefing moderator Tomas Griebling, MD, of the University of Kansas in Kansas City. Nonetheless, the lessons learned from the study can be applied immediately to clinical practice.
"Increasing physical activity and reducing energy intake is good advice for everyone," Griebling told MedPage Today. "More and more, we're learning that following common-sense lifestyle practices has a favorable effect on a wide range of conditions, and now we can add kidney stones to the list."
Source : MedPage Today
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Exercise as good as massage for sore muscles
The aches and pains people suffer after working out more than usual can be relieved just as well by exercise as by massage, according to a new study.
"It's a common belief that massage is better, but it isn't better. Massage and exercise had the same benefits," said Lars Andersen, the lead author of the study and a professor at the National Research Center for the Working Environment in Copenhagen.
Earlier research has shown that massage can offer some relief from work out soreness.
To see how well light exercise compares, Andersen and his colleagues asked 20 women to do a shoulder exercise while hooked up to a resistance machine.
The women shrugged their shoulders while the machine applied resistance, which engaged the trapezius muscle between the neck and shoulders.
Two days later, the women came back to the lab with aching trapezius muscles. On average they rated their achiness as a five on a 10 point scale, up from 0.8 before they had done the shoulder work out.
Then the women received a 10-minute massage on one shoulder and did a 10-minute exercise on the other shoulder. Some women got the massage first, while others did the exercise first.
The exercise again involved shoulder shrugs; this time the women gripped an elastic tube held down by their foot to give some resistance. (Hygenic Corporation, which makes the tubing used in the study, supported the study.)
Andersen's group found that, compared to the shoulder that wasn't getting any attention, massage and exercise each helped diminish muscle soreness.
The effect peaked 10 minutes after each treatment, with women reporting a reduction in their pain of 0.8 points after the warm up exercise and 0.7 points after the massage.
"It's a moderate change," said Andersen, whose study appeared in the Journal of Strength and Conditioning Research.
He said he expects that athletes would notice a difference in having their soreness reduced by this amount.
"I think that for athletes...by reducing soreness then they're able to perform better, but we didn't measure this. But if you are sore your movements are very stiff and it's difficult to perform," he said.
Andersen said he'd like to see future studies track whether warming up the muscles to relieve soreness does indeed impact how well athletes perform.
The study suggests that "maybe (massage or exercise) has some benefit for individuals prior to an activity, even though the benefit may be short-lasting," said Jason Brumitt, of the School of Physical Therapy at Pacific University, who was not involved in the research.
It's not clear how massage or exercise would relieve soreness, but Brumitt said that it's thought that they help to clear out metabolic byproducts associated with tissue damage.
Source : Reuters Health via Journal of Strength and Conditioning Research
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Fitness in 40s, 50s Tied to Later Dementia Risk
Individuals with the highest levels of cardiorespiratory fitness during middle age were significantly less likely to develop dementia in their senior years, a long-term prospective study suggested.
Among nearly 20,000 participants in the Cooper Center Longitudinal Study, those in the highest quintile of cardiorespiratory fitness at roughly age 50 were 36% less likely than those in the lowest quintile (adjusted hazard ratio 0.64, 95% CI 0.54 to 0.77) to be diagnosed with dementia after age 65, according to Laura F. DeFina, MD, of the Cooper Institute in Dallas, and colleagues.
The risk of all-cause dementia did not appear to be affected by whether participants had a stroke during follow-up, nor did educational attainment appear to make a difference, the researchers reported online in Annals of Internal Medicine.
Although the observational study could not prove that cardiorespiratory fitness actually prevents onset of dementia later on, DeFina and colleagues indicated that such a causal connection is plausible.
For example, greater fitness would reduce the incidence of other known risk factors for dementia such as diabetes and hypertension, the researchers noted. Fitness has also been linked to greater brain volume, and some evidence points to connections between physical activity and neural plasticity, neurotrophic factors, and beta-amyloid protein deposits.
"Future studies should address the dose-response relationship with physical activity needed to modify fitness levels to inform public health recommendations for dementia prevention," DeFina and colleagues wrote.
"In addition, studies on the effect of midlife physical activity and fitness levels on brain structure and function may further elucidate the mechanism(s) of the protective effect of fitness levels."
In an accompanying editorial, a prominent researcher in dementia agreed that a causal relationship was credible enough to warrant action by clinicians.
"Physical activity seems to be a reasonable prescription for dementia prevention," wrote Mary Sano, PhD, of Mount Sinai School of Medicine in New York City, given the weight of evidence to which the current study adds.
Another dementia expert, David Geldmacher, MD, of the University of Alabama at Birmingham, told MedPage Today that the potential benefit for dementia risk is worth bringing up with patients, even though recommendations of physical activity and fitness are familiar to everybody.
Compared with the benefit of exercise for cardiovascular health, "many physicians are not as clear that [the benefit] also translates to dementia risk," Geldmacher said.
"Many patients will [say] that, 'Well, it's not so bad if I die of a heart attack,' but they fear Alzheimer's disease very much. So knowing that fitness can reduce the Alzheimer risk may give them further motivation to follow through with an exercise and fitness plan."
The current study drew on data collected as part of the long-running Cooper Center study, begun more than 40 years ago under the leadership of Kenneth Cooper, MD, the famous advocate of aerobic exercise. It began with individuals who came to Cooper's wellness-oriented clinic, with later participation by people referred to it as part of employer-based programs.
DeFina and colleagues analyzed data on 19,458 participants, after excluding about 9,000 for whom later Medicare records were not available or with incomplete baseline data, those with a history of heart attack or stroke at baseline, those entering Medicare because of disability or a need for renal dialysis, and those with dementia or stroke prior to 2000 or at age 65 or younger (67 or younger for dementia).
All participants had a treadmill test when entering the study. Their mean age was 50. Fitness was calculated from time on the treadmill and the final speed and grade.
Participants' Medicare records were examined for diagnoses of dementia at ages 70, 75, 80, and 85. DeFina and colleagues calculated the risk for such a diagnosis according to quintiles of cardiorespiratory fitness, after adjusting for sex, age at baseline exam, year of exam, and other baseline factors including fasting glucose, cholesterol, body mass index, blood pressure, and smoking status.
Mean treadmill times for the five quintiles ranged from 8.1 maximal metabolic equivalents in the lowest to 13.3 in the highest.
Kaplan-Meier curves calculated in the study showed that, by age 92, about 52% of surviving participants in the two highest quintiles remained dementia-free, compared with 40% of those in the lowest quintile (P<0.001).
The risk did not appear to differ between participants with a stroke recorded prior to dementia diagnosis versus those without stroke (0.74 in both groups for the highest quintile relative to the lowest). This finding suggests "that the association between higher fitness level and risk for dementia is independent of intervening cerebrovascular disease," DeFina and colleagues wrote.
There was also no statistically significant relationship between dementia risk and educational level. But the authors cautioned that education data was available for only about 20% of the sample and, in those participants, the average attainment was relatively high (mean 15.7 years, SD 2.6).
Other limitations to the analysis included the reliance on Medicare data for dementia outcomes and the largely white, affluent, and healthy population represented in the Cooper Center study. DeFina and colleagues also pointed out that the baseline data did not cover all lifestyle factors that may correlate with fitness.
Source : MedPage Today
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Walking linked to fewer strokes in women
Women who walk at least three hours every week are less likely to suffer a stroke than women who walk less or not at all, according to new research from Spain.
"The message for the general population remains similar: regularly engaging in moderate recreational activity is good for your health," lead author José María Huerta of the Murcia Regional Health Authority in Spain told Reuters Health.
Past studies have also linked physical activity to fewer strokes, which can be caused by built-up plaque in arteries or ruptured blood vessels in the brain.
While the current study cannot prove that regular walking caused fewer strokes to occur in the women who participated, it contributes to a small body of evidence for potential relationships between specific kinds of exercise and risk for specific diseases.
Women who walked briskly for 210 minutes or more per week had a lower stroke risk than inactive women but also lower than those who cycled and did other higher-intensity workouts for a shorter amount of time.
In all, nearly 33,000 men and women answered a physical activity questionnaire given once in the mid-1990s as part of a larger European cancer project. For their study, Huerta and his team divided participants by gender, exercise type and total time spent exercising each week.
The authors, who published their findings in the journal Stroke, checked in with participants periodically to record any strokes. During the 12-year follow-up period, a total of 442 strokes occurred among the men and women.
The results for women who were regular walkers translated to a 43 percent reduction in stroke risk compared to the inactive group, Huerta said.
There was no reduction seen for men based on exercise type or frequency, however.
"We have no clear explanation for this," Huerta wrote in an email. He hypothesized that the men may have entered the study in better physical condition than the women, but there was no evidence to support that guess.
Huerta also declined to compare the study participants' risk levels to those of the general population, citing the subjects' unusual characteristics: a majority of men and women in the study were blood donors, who tend to be in good health in order to give blood.
"I wouldn't make much of the results because they are for a very specific population," Dr. Wilson Cueva of the University of Chicago in Illinois said.
Cueva, who was not involved with the research, pointed out that the study relied too heavily on subjective measurements, like the participants' memory of exercise routines.
"There is no objective way to measure how much exercise they actually did," he said.
Each year in the U.S., about 795,000 people suffer a stroke, according to the American Heart Association. Put another way, one American has a stroke every 40 seconds and dies from one every four minutes.
Despite a recent dip in strokes attributed to better blood pressure control and anti-smoking campaigns, the World Health Organization (WHO) predicts that stroke cases will increase as the global population continues to grow older.
Guidelines set by the WHO and U.S. Centers for Disease Control and Prevention recommend at least 150 minutes - or two-and-a-half hours - of moderate exercise such as brisk walking each week.
Cueva urged health consumers to heed those guidelines for now. The way the Spanish study was designed, it's difficult to draw any conclusions he told Reuters Health. But, "We know that exercise is related to reduced risk of stroke and other diseases."
Source : Reuters
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Midlife fitness staves off chronic disease at end of life: study
Being physically fit during your 30s, 40s, and 50s not only helps extend lifespan, but it also increases the chances of aging healthily, free from chronic illness, investigators at UT Southwestern Medical Center and The Cooper Institute have found.
For decades, research has shown that higher cardiorespiratory fitness levels lessen the risk of death, but it previously had been unknown just how much fitness might affect the burden of chronic disease in the most senior years – a concept known as morbidity compression. "We've determined that being fit is not just delaying the inevitable, but it is actually lowering the onset of chronic disease in the final years of life," said Dr. Jarett Berry, assistant professor of internal medicine and senior author of the study available online in the Archives of Internal Medicine. Researchers examined the patient data of 18,670 participants in the Cooper Center Longitudinal Study, research that contains more than 250,000 medical records maintained over a 40-year span. These data were linked with the patients' Medicare claims filed later in life from ages 70 to 85. Analyses during the latest study showed that when patients increased fitness levels by 20 percent in their midlife years, they decreased their chances of developing chronic diseases – congestive heart failure, Alzheimer's disease, and colon cancer – decades later by 20 percent. "What sets this study apart is that it focuses on the relationship between midlife fitness and quality of life in later years. Fitter individuals aged well with fewer chronic illnesses to impact their quality of life," said Dr. Benjamin Willis of The Cooper Institute, first author on the study. This positive effect continued until the end of life, with more-fit individuals living their final five years of life with fewer chronic diseases. The effects were the same in both men and women. These data suggest that aerobic activities such as walking, jogging, or running translates not only into more years of life but also into higher quality years, compressing the burden of chronic illness into a shorter amount of time at the end of life, Dr. Berry said. According to the National Heart, Lung, and Blood Institute (NHLBI), adults should get at least 2 ½ hours of moderate to intense aerobic activity each week to ensure major heart and overall health benefits.
Source : MedicalXpress
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Does Gatorade Actually Work?
A top science journal has issued a blistering indictment of the sports drink industry.
Just in time for the Summer Olympics in London, a top science journal has issued a blistering indictment of the sports drink industry. According to the series of reports from BMJ (formerly British Medical Journal ), the makers of drinks like Gatorade and Powerade have spent millions in research and marketing in recent decades to persuade sports and medical professionals, not to mention the rest of us suckers, that a primal instinct—the sensation of thirst—is an unreliable guide for deciding when to drink. We've also been battered with the notion that boring old water is just not good enough for preventing dehydration. I've been as susceptible to this scam as anyone else; I knew, or thought I knew, that if I'm thirsty after my half-hour go-round on the elliptical trainer, it means I was underhydrated to begin with. So for years I've been trying to remember to ignore my lack of thirst and make myself drink before working out. Not any more.
The BMJ's package of seven papers on sports performance products packs a collective wallop. The centerpiece is a well-reported investigation of the long-standing financial ties between the makers of Gatorade (PepsiCo), Powerade (Coca-Cola, an official Olympic sponsor), and Lucozaid (GlaxoSmithKline) with sports associations, medical groups, and academic researchers. It should come as no great surprise that the findings and recommendations that have emerged through these affiliations have tended to include alarming warnings about dehydration and electrolyte imbalance—warnings that conveniently promote the financial interests of the corporate sponsors.
And who knew there was something called the Gatorade Sports Science Institute ? According to the BMJ investigation, "one of GSSI's greatest successes was to undermine the idea that the body has a perfectly good homeostatic mechanism for detecting and responding to dehydration—thirst." The article quotes the institute's director as having declared, based on little reliable evidence, that "the human thirst mechanism is an inaccurate short-term indicator of fluid needs."
Another study in the BMJ package finds that the European Food Safety Authority, which is authorized to assess health claims in food labels and ads, has relied on a seriously flawed review process in approving statements related to sports drinks. A third study reports that hundreds of performance claims made on websites about sports products, including nutritional supplements and training equipment as well as drinks, are largely based on questionable data, and sometimes no apparent data at all. One overall theme emerging from the various papers is that much of the research cited was conducted with elite and endurance athletes, who have specific nutritional and training needs; any such findings, however, should not be presumed to hold for the vast majority of those who engage in physical activity.
Critics have long blasted sports drinks as being loaded with calories and unnecessary ingredients. (Not to mention concerns about the environmental costs of producing, shipping, and discarding all those millions of plastic bottles.) Yet the product category represents a lucrative and growing market, with US sales of about $1.6 billion a year, according to the BMJ. In fact, Powerade is the official sports drink of the London Olympics, and Coca-Cola is hyping the brand with a campaign featuring top-tier athletes.
The BMJ papers address two related but distinct questions: Should people who exercise seek to proactively replace fluids lost, or can they rely on thirst to guide them during and after physical activity? And when they rehydrate, do they need all the salts, sugars, and other ingredients dumped into sports drinks, or is water fine? The correct answers are: best to rely on thirst, and water is fine. All that stuff about replacing electrolytes and so on you've been hearing all these years? Never mind! The evidence doesn't support it.
Overhydration presents a far greater risk of serious complications, and even death, than dehydration. In a commentary accompanying the investigations in the journal, Timothy Noakes, chair of sports science at the University of Cape Town, points out that overhydration presents a far greater risk of serious complications, and even death, than dehydration. Moreover, he notes, the notion that fluid and electrolytes must be immediately replaced is based on a fundamental misunderstanding of our past as "long distance persistence hunters" in arid regions of Africa.
"Humans do not regulate fluid balance on a moment to moment basis," Noakes writes. "Because of our evolutionary history, we are delayed drinkers and correct the fluid deficits generated by exercise at, for example, the next meal, when the electrolyte (principally sodium but also potassium) deficits are also corrected…People optimize their hydration status by drinking according to the dictates of thirst. Over the past 40 years humans have been misled—mainly by the marketing departments of companies selling sports drinks—to believe that they need to drink to stay 'ahead of thirst' to be optimally hydrated."
Source : Alternet
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Comparison of coconut water and a carbohydrate-electrolyte sport drink on measures of hydration and physical performance in exercise-trained men
Douglas S Kalman1, Samantha Feldman1, Diane R Krieger1 and Richard J Bloomer2*
1 Miami Research Associates, Nutrition/Endocrinology Department, 6141 Sunset Drive, Suite 301, Miami, FL 33143
2 The University of Memphis, Cardiorespiratory/Metabolic Laboratory, Department of Health and Sport Sciences, 106 Roane Fieldhouse, Memphis, TN 38152
Background Sport drinks are ubiquitous within the recreational and competitive fitness and sporting world. Most are manufactured and artificially flavored carbohydrate-electrolyte beverages. Recently, attention has been given to coconut water, a natural alternative to manufactured sport drinks, with initial evidence indicating efficacy with regard to maintaining hydration. We compared coconut water and a carbohydrate-electrolyte sport drink on measures of hydration and physical performance in exercise-trained men.
Methods Following a 60-minute bout of dehydrating treadmill exercise, 12 exercise-trained men (26.6 ± 5.7 yrs) received bottled water (BW), pure coconut water (VitaCoco®: CW), coconut water from concentrate (CWC), or a carbohydrate-electrolyte sport drink (SD) [a fluid amount based on body mass loss during the dehydrating exercise] on four occasions (separated by at least 5 days) in a random order, single blind (subject and not investigators), cross-over design. Hydration status (body mass, fluid retention, plasma osmolality, urine specific gravity) and performance (treadmill time to exhaustion; assessed after rehydration) were determined during the recovery period. Subjective measures of thirst, bloatedness, refreshed, stomach upset, and tiredness were also determined using a 5-point visual analog scale.
Results Subjects lost approximately 1.7 kg (~2% of body mass) during the dehydrating exercise and regained this amount in a relatively similar manner following consumption of all conditions. No differences were noted between coconut water (CW or CWC) and SD for any measures of fluid retention (p > 0.05). Regarding exercise performance, no significant difference (p > 0.05) was noted between BW (11.9 ± 5.9 min), CW (12.3 ± 5.8 min), CWC (11.9 ± 6.0 min), and SD (12.8 ± 4.9 min). In general, subjects reported feeling more bloated and experienced greater stomach upset with the CW and CWC conditions.
All tested beverages are capable of promoting rehydration and supporting subsequent exercise. Little difference is noted between the four tested conditions with regard to markers of hydration or exercise performance in a sample of young, healthy men. Additional study inclusive of a more demanding dehydration protocol, as well as a time trial test as the measure of exercise performance, may more specifically determine the efficacy of these beverages on enhancing hydration and performance following dehydrating exercise.
Source Journal of The International Society of Sports Nutrition
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Playing Sports Helps Teens Fight Fat
Team sports may fight weight problems better than other forms of exercise among high schoolers, researchers found.
Playing in three or more sports per year cut risk of overweight or obesity by 27% compared with no participation (95% CI 0.61 to 0.87), according to results from a longitudinal survey-based study by Keith Drake, BA, of Dartmouth College in Lebanon, N.H., and colleagues.
Walking or biking to school cut risk of obesity but not overweight, while gym class had no impact on weight status, the group reported in the August issue of Pediatrics.
"High school sports participation typically involves regular practices and competitions, leading to consistent moderate to strenuous activity, which may explain the strength of its relationship with weight status compared with other forms of physical activity," they wrote.
At a time when many schools are cutting back on sports over budget concerns, focusing in on what works best is key, Drake's group suggested.
"Increasing opportunities for all adolescents, regardless of athletic ability, to participate in sports should be prioritized for obesity prevention," they argued.
The researchers analyzed data from telephone surveys with 1,718 high school students and their parents as part of a larger 7-year longitudinal study at 26 randomly selected New Hampshire and Vermont public schools.
Among the mostly ninth and 10th graders, 29% were overweight or obese and 13% were obese.
Participation in school sports teams was common:
- 17.4% played on one team over the course of the prior year
- 18.6% played on two teams over the past year
- 35.3% played on three or more sports teams per year
Teens in two or more sports in the prior 12 months were 22% less likely to be overweight or obese and 39% less likely to be obese than those who didn't participate (adjusted P<0.05 and P<0.01, respectively).
Those on three or more teams over the same period were 27% less likely to be overweight or obese and 39% less likely to be obese than those not on any sports teams (both adjusted P<0.001).
Active commuting to school by foot or bike also tended to help against obesity, but only reached statistical significance for the 10% of kids who did so on more than 3.5 days a week (adjusted risk ratio 0.67, P<0.05). Active commuting had no impact on combined risk of overweight or obesity.
More frequent walking or cycling other places, playing sports or other physical activity for fun, or having had physical education class in the prior week didn't have an impact on either weight category.
Gym has been shown to help for younger children in prior studies, but "PE classes may not involve a substantial enough duration or intensity level of physical activity to affect overall energy balance in high school students," the researchers suggested.
An attributable risk analysis controlling for all other factors suggested that if all high school students were to play on two sports a year:
- Rates of overweight or obesity would fall by a relative 10%, from 29% to 26%
- Obesity prevalence would drop by 26%, from 13% to 10%
The researchers cautioned that those estimates assumed a causal link between physical activity and weight status. A bigger limitation was the study's reliance on self-reported height, weight, and physical activity.
National rates of sports participation are lower and obesity rates higher than in the cohort studied, the group noted.
"Our estimates of the potential benefit of increasing sports participation would be even higher in areas with lower rates of sports participation and higher rates of overweight/obesity, as in most of the country," they concluded.
Primary source: Pediatrics
Drake KM, et al "Influence of sports, physical education, and active commuting to school on adolescent weight status" Pediatrics 2012; DOI: 10.1542/peds.2011-2898.
Source : MedPage Today
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Meditation or Exercise May Help Acute Respiratory Infections, Study Finds
According to a recent study, exercising or practicing meditation may be effective in reducing acute respiratory infections. Acute respiratory infections, which are caused by influenza and other viruses, are very common illnesses and account for millions of doctor visits and lost school and work days each year. Previous research has suggested that enhancing general physical and mental health may offer protection against these illnesses. Findings from this NCCAM-funded study were published in the journal Annals of Family Medicine.
Researchers from the University of Wisconsin-Madison randomly assigned 154 people, aged 50 and older, to one of three groups: a mindfulness meditation group, an exercise group, or a wait-list control group. Participants in the meditation group received training in mindfulness-based stress reduction (a type of meditation based on the idea that an increased awareness of physical, emotional, and cognitive manifestations of stress may lead to a healthier mind-body response to stress). Participants in the exercise group received instruction and practiced moderately intensive exercise (using stationary bicycles, treadmills, and other equipment) during group sessions, and walked briskly or jogged for home exercise. Both interventions lasted 8 weeks, consisting of 2.5-hour group sessions each week and 45 minutes of daily at-home practice.
The severity of each acute respiratory infection that occurred during the study was assessed through a participant survey. In addition, a nasal wash was collected within 3 days of participants experiencing symptoms and analyzed for specific indicators, some of which are linked to the severity of symptoms. Participants answered questionnaires assessing psychosocial measures that could potentially explain links between behavioral interventions and acute respiratory illness outcomes. They also reported any visits to health care facilities or missed work or school activities.
The researchers observed substantial reductions in acute respiratory illness among those in the exercise group, and even greater benefits among those in the meditation group. While not all of the observed benefits were statistically significant, the researchers noted that the magnitude of the observed reductions in illness was clinically significant. They also found that compared to the control group, there were 48 percent fewer days of work missed due to acute respiratory infections in the exercise group, and 76 percent fewer in the meditation group. Researchers stated that these findings are especially noteworthy because apart from hand-washing, no acute respiratory infection prevention strategies have previously been proven. The researchers concluded that future studies are needed to confirm these findings.
Barrett B, Hayney MS, Muller D, et al. Meditation or exercise for preventing acute respiratory infection: a randomized controlled trial. Annals of Family Medicine. 2012;10:337-346.
Source : NCCAM
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Exercise, even mild physical activity, may reduce breast cancer risk
A new analysis has found that physical activity – either mild or intense and before or after menopause – may reduce breast cancer risk, but substantial weight gain may negate these benefits. Published early online in CANCER, a peer-reviewed journal of the American Cancer Society, the findings indicate that women can reduce their breast cancer risk by exercising and maintaining their weight.
While studies have shown that physical activity reduces breast cancer risk, many questions remain. For example, how often, how long, and how intense does physical activity have to be to provide benefits? Also, do women with all body types experience a reduced risk when they exercise, and does exercise reduce the risk of all types of breast cancer?
To investigate, Lauren McCullough, of the University of North Carolina Gillings School of Global Public Health in Chapel Hill, and her colleagues looked for a link between recreational physical activity, done at different time points in life, and the risk of developing breast cancer.
The study included 1,504 women with breast cancer (233 noninvasive and 1,271 invasive) and 1,555 women without breast cancer who were 20 to 98 years old and were part of the Long Island Breast Cancer Study Project, an investigation of possible environmental causes of breast cancer.
Women who exercised either during their reproductive or postmenopausal years had a reduced risk of developing breast cancer. Women who exercised 10 to 19 hours per week experienced the greatest benefit with an approximate 30% reduced risk. Risk reductions were observed at all levels of intensity, and exercise seemed to preferentially reduce the risk of hormone receptor positive breast cancer (ER or PR positive), which is the most commonly diagnosed tumor type among American women.
"The observation of a reduced risk of breast cancer for women who engaged in exercise after menopause is particularly encouraging given the late age of onset for breast cancer," said McCullough.
When the researchers looked at the joint effects of physical activity, weight gain, and body size, they found that even active women who gained a significant amount of weight – particularly after menopause – had an increased risk of developing breast cancer, indicating that weight gain can eliminate the beneficial effects of exercise on breast cancer risk.
Source : Science Codex
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Get Moving: Daily Exercise May Reduce Alzheimer’s Disease Risk at Any Age
ST. PAUL, Minn. – Daily physical exercise may reduce the risk of Alzheimer’s disease, even in people over the age of 80, according to a study published in the April 18, 2012, online issue of Neurology®, the medical journal of the American Academy of Neurology. “The study showed that not only exercise but also activities such as cooking, washing the dishes and cleaning are associated with a reduced risk of Alzheimer’s disease,” said study author Aron S. Buchman, MD, with Rush University Medical Center in Chicago and a member of the American Academy of Neurology. “These results provide support for efforts to encourage physical activity in even very old people who might not be able to participate in formal exercise but can still benefit from a more active lifestyle.”
For the study, a group of 716 people with an average age of 82 wore an actigraph, a device that monitors activity, on their non-dominant wrist continuously for 10 days. All exercise and non-exercise was recorded. They also were given annual tests during the four-year study that measured memory and thinking abilities. During the study, 71 people developed Alzheimer’s disease.
Participants also self-reported their physical and social activity. Buchman said this is the first study to use an objective measurement of physical activity in addition to self-reporting. “This is important because people may not be able to remember the details correctly,” he said.
The research found that people in the bottom 10 percent of daily physical activity were more than twice as likely to develop Alzheimer’s disease as people in the top 10 percent of daily activity.
The study also showed that those people in the bottom 10 percent of intensity of physical activity were almost three times as likely to develop Alzheimer’s disease as people in the top 10 percent of intensity of physical activity.
“Since the actigraph was attached to the wrist, activities like cooking, washing the dishes, playing cards and even moving a wheelchair with a person’s arms were associated with a lower Alzheimer’s risk,” said Michal Schnaider-Beeri, PhD, of Mount Sinai School of Medicine in New York in an accompanying editorial. “These are low-cost, easily accessible and side-effect free activities people can do at any age, including very old age, to possibly prevent Alzheimer’s disease.”
The study was supported by the National Institute on Aging, the Illinois Department of Public Health and the Robert C. Borwell Endowment Fund.
Source : Newswire
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Simple Tests May Flag Dementia, Stroke Risk.
_Walking speed and hand-grip strength during middle age correlated with cognitive function and stroke risk in older adults, suggesting simple tests might aid diagnosis of the two conditions, according to data from a large cohort study.
During 11 years of follow-up, slower walking speed at baseline was associated with a 50% rise in the hazard for dementia. Brain volume and performance on a variety of tests of cognitive function also were significantly lower in slower walkers.
Grip strength did not influence stroke risk in the overall cohort, but a higher baseline grip strength was associated with a 42% reduction in stroke risk among individuals 65 and older, as will be reported here in April at the American Academy of Neurology meeting.
"These are basic office tests [that] can provide insight into the risk of dementia and stroke and can be easily performed by a neurologist or general practitioner," Erica C. Camargo, MD, PhD, of Boston Medical Center, said in a statement.
"While frailty and lower physical performance in elderly people have been associated with an increased risk of dementia, we weren't sure until now how it impacted people of middle age," she added.
The findings came from an analysis of data from the Framingham Offspring Cohort, children of the original participants in the long-running study of the natural history of cardiovascular disease.
Camargo and colleagues analyzed data for 2,410 participants in the offspring cohort study, mean age 62, all of whom were stroke- and dementia-free at baseline. The initial workup included assessments of walking speed, grip strength, and cognitive function, as well as MRI scans of the brain.
The investigators statistically related age-standardized grip strength and walking speed with baseline cerebral volume estimated by MRI, with age- and education-standardized cognitive function and with stroke and dementia incidence.
During follow-up, 34 participants developed dementia, and 79 had strokes or transient ischemic attacks (TIAs). Slower walking speed had a significant correlation with:
- Increased stroke risk (HR 1.50, P=0.020)
- Lower total cerebral volume (P=0.007)
- Poorer performance on tests of various aspects of memory (visual reproduction, P=0.009; paired associate learning, P<0.001; executive function, P=0.004; visuo-perceptual function, P=0.002; and language, P=0.006)
Increasing grip strength also was associated with:
- Total cerebral brain volume (P<0.001)
- Visual reproduction (P<0.001)
- Executive function (P=0.009)
- Visuo-perceptional function (P<0.001)
- Language (P=0.002)
- Better abstraction (P=0.009)
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The Need for Exercise
UPI just published a poll that says that more than 80% of American adults have a regular exercise regimen. If true, that would be very exciting. Then again, it could also be viewed as a major black eye for exercise since it would seem that all this activity is having little impact on overall health in the United States. The truth of the matter, though, is that exercise is vital to health and has enormous impact. The poll, on the other hand, is probably much less than it seems.
First of all, polls themselves are suspect since people often idealize their answers -- telling pollsters what they wish they were doing, rather than what they are actually doing. Then too, on closer inspection, the numbers tell a slightly different story than the headlines would suggest. The poll found that 16% of respondents copped to the fact that they never exercised at all, and 19% said that their regimen consisted of exercising once a week. Quite simply, once a week does not qualify as a regular regimen despite the claims of the pollsters. That means that approximately 35% of Americans are not participating in any form of regular exercise -- about the same percentage considered clinically obese. Hmm!
And still another 27% said that they exercised less than 30 minutes at a time. Now if you consider the next group in the poll, the 29% who exercise only 2-3 times per week, you realize that many of them are really only exercising for a total of 60-90 minutes a week -- the barest minimum of a routine. Throw those people into the mix, and you're now looking at a total of about 60% -- about the same percentage that qualifies as overweight in the United States. When all is said and done, you can see a direct correlation between lack of sufficient exercise and excess weight, but the importance of exercise goes far beyond obesity. Exercise impacts almost every aspect of health. It can:
- Reduce the risk of premature death
- Reduce the risk of heart disease
- Reduce high blood pressure
- Reduce high cholesterol
- Reduce the risks of many cancers, including colon and breast cancer
- Reduce the risk of developing diabetes
- Reduce fat and optimize body weight
- Build and maintain healthy muscles, bones, and joints
- Reduce depression and anxiety
- Enhance performance in work and sport
Let's start by talking about cardio/aerobic exercise.
Cardio/aerobic exercise By definition, cardio/aerobic exercise is brisk physical activity that requires the heart and lungs to work harder to meet the body's increased oxygen demand. Aerobic exercise promotes the circulation of oxygen through the blood. The key part of the definition here is the word oxygen. The defining aspect of aerobic exercise is that it is of sufficient intensity to force the heart and lungs to work harder, and yet of low enough intensity to facilitate adequate oxygen transfer to the muscle cells so that no buildup of lactic acid is observed. Another way of looking at aerobic exercise is that it involves repetitive movement of large muscle groups (such as your arms, legs, and hips) -- with all of the needed energy supplied by the oxygen you breathe. When you're aerobically fit, your body takes in and utilizes oxygen more efficiently -- to sustain the repetitive muscle movement. Benefits include:
- Improved heart and lung function
- Lower heart rate and blood pressure
- Increased blood supply to muscles and improved ability to use oxygen
- Increased HDL cholesterol (the good cholesterol)
- Decreased triglycerides
- Reduced body fat and improved weight control
- Improved glucose tolerance and reduced insulin resistance
- Enhanced immune function, which means
- Increased resistance to viral and bacterial infection
- Increased resistance to cancer
- Lowered blood sugar levels and reduced risk of diabetes
- Longer life expectancy
Strength Training Strength training involves the use of weights or some other form of resistance to build muscle and increase strength. Its benefits include:
- Increased muscle strength
- Increased tendon and ligament strength
- Reduced body fat and increased muscle mass
- Better balance
- Lower blood cholesterol
- Improved glucose tolerance and insulin sensitivity
What kinds of strength training options are available? Again, as with aerobics, there is a world of choices. There are free weights, stacked weight machines, and Nautilus circuits at the gym. There's resistance training as found in Soloflex and Bowflex machines and push/pull resistance as found in the Delta Trimax machine. Then there's Pilates equipment and the Total Gym that use your own body weight as resistance. Any and all can work. Choose one that works for you and that you can do easily and are willing to do regularly.
It's worth noting that weight training is the ultimate way to burn calories fast. A pound of muscle burns up to nine times the calories of a pound of fat. In other words, strength training increases your resting metabolic rate, which is the number of calories you burn while sleeping or sitting. The trick is that muscle is active tissue. That is, it requires a lot of energy just to maintain itself. In fact, every pound of new muscle you add to your body will burn about 60 calories per day. Adding just 10 pounds of muscle to your body, will burn off 62 pounds of fat over the next year -- even while you are sleeping! And it will continue to do so the next year…and the next.
Weight Bearing Exercise Weight bearing exercise is actually a subset of certain aerobic and strength training exercises. It is exercise in which you force your body to support weight (your own included) while exercising. Studies have shown that weight bearing exercise can help slow down the rate of bone loss and osteoporosis, and therefore reduce fractures. How does it do this? First, weight-bearing exercise directly stimulates bone formation. Then, it strengthens muscles that in turn pull and tug on bones. This pulling action actually causes the bones to become denser and stronger. Weight-bearing activities at any age benefit bone health. Studies have shown that even people in their 90's can increase bone mass with weight bearing exercise.
The best weight bearing exercises are: weight-lifting, jogging, hiking with a back pack, stair-climbing, step aerobics, racquet sports, and other activities that require your muscles to work against gravity. Swimming and simple walking don't do the trick. One exceptionally useful form of weight bearing exercise is rebounding. The act of rebounding makes use of g-forces, just like astronauts training in a centrifuge. Rebounding can actually achieve momentary g-forces of 3.5, which means that the bones of a 150 lb person will momentarily have to bear 525 lbs of weight on each bounce. That's a lot of weight bearing.
Note: the benefits of weight-bearing exercise are site-specific. This means that you strengthen only the bones used directly in the exercise. In other words, it's a good idea to participate in a variety of weight-bearing exercises. To maintain the bone-building benefits, the exercise needs to be continued on a regular basis.
Stretching Stretching is the step child of exercise, with more lip service paid to it than actual practice. Stretching though is crucial to good health. The usual benefits cited include:
- Reduced muscle tension
- Injury prevention
- Increased range of movement in the joints
- Enhanced muscular coordination
- Increased circulation of the blood to various parts of the body
- Increased energy levels (resulting from increased circulation)
What kinds of stretching are good? Yoga is probably the best stretching exercise there is, but Pilates works well too. If nothing else, just do 5-10 minutes of simple stretching after your daily exercise routine as part of your cool down time.
Note: It is not by accident that at 59 years old, I can still do full splits.
Resistance Breathing Proper breathing is topic worthy of its own newsletter, but for now, let's just focus on the advantages of resistance breathing. The concept is simple: putting a device in your mouth that restricts (in a controlled manner) your inhalations and exhalations, which forces your lungs to work harder. This, in turn, strengthens the muscles that makes your lungs work and increases their capacity. There are a number of such devices widely available on the internet and in health magazines. They tend to run $20-40. The investment is well worth it since this type of exercise can significantly improve the strength of your respiratory muscles and increase your lung capacity.
How much of a benefit are we talking about?
Studies have shown that these devices can increase breathing endurance by close to 300%. Considering how fundamental oxygen is to health, it's not hard to see the short and long-term health and performance advantages of doing so.
Balance One other key aspect of exercise is balance. Why? Because like all other physical abilities, it diminishes with age unless we consciously exercise it. Is that a bad thing? Only if you fall down and break your hip or wrist. Here's a simple balance exercise you can do daily. It takes just a couple of minutes and will produce quick improvement.
- Stand while holding for support, with one hand, the back edge of a chair set beside you.
- Bend the leg nearest to the chair at the knee 90 degrees so that your knees are still together and the foot of the bent leg is projected out behind you.
- Get used to balancing on the one leg while holding the chair.
- Then turn to the other side and do the other leg.
- Try taking your hand off the chair and balancing on the one leg without support from the chair.
- As you get more comfortable doing this, try to stop using your arms for balance and pull your hands in, palms together in front of your chest, like in a Far East prayer position. This will force the act of balance to the muscles of one leg.
- Try closing your eyes and holding the pose for 30 seconds.
Conclusion Exercise is as important to good health as proper nutrition. Speaking of which, your need for proper nutrition is increased by exercise.
- You will need more quality protein to build the muscles you are exercising. I know soy and whey are the "in vogue" supplements for body builders. I much prefer the combination of rice protein and yellow pea protein. It is virtually of the same quality and bioavailability as those other sources, but has one huge advantage. It is hypoallergenic and extremely easy to digest.
- You also need quality carbohydrates, especially ultra-long-chain carbohydrates (ULCs) such as pre-sprouted barley. ULCs release energy over several hours and do not spike sugar levels.
- You also need high quality fats -- Omega-3s and 9s in particular.
- When you are exercising, you utilize more oxygen, which by definition produces more free radicals so you will need more antioxidants to clear them. Look for a full spectrum antioxidant, rather than a single source wonder supplement.
- And you will want higher intake of minerals (particularly electrolytes) and water soluble vitamins (vitamin C, and all of the B vitamins) since you will be using them up and sweating them out at an accelerated rate. As a side note, instead of drinking high-sugar sports beverages, you might want to consider just adding liquid trace minerals to your water.
Bottom line: If you don't move you die. Exercise fundamentally changes every system and function in your body.
Source : Jon Barron Newsletter
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Physical activity impacts overall quality of sleep
People sleep significantly better and feel more alert during the day if they get at least 150 minutes of exercise a week, a new study concludes. A nationally representative sample of more than 2,600 men and women, ages 18-85, found that 150 minutes of moderate to vigorous activity a week, which is the national guideline, provided a 65 percent improvement in sleep quality. People also said they felt less sleepy during the day, compared to those with less physical activity.
The study, out in the December issue of the journal Mental Health and Physical Activity, lends more evidence to mounting research showing the importance of exercise to a number of health factors. Among adults in the United States, about 35 to 40 percent of the population has problems with falling asleep or with daytime sleepiness.
"We were using the physical activity guidelines set forth for cardiovascular health, but it appears that those guidelines might have a spillover effect to other areas of health," said Brad Cardinal, a professor of exercise science at Oregon State University and one of the study's authors.
"Increasingly, the scientific evidence is encouraging as regular physical activity may serve as a non-pharmaceutical alternative to improve sleep."
After controlling for age, BMI (Body Mass Index), health status, smoking status, and depression, the relative risk of often feeling overly sleepy during the day compared to never feeling overly sleepy during the day decreased by 65 percent for participants meeting physical activity guidelines.
Similar results were also found for having leg cramps while sleeping (68 percent less likely) and having difficulty concentrating when tired (45 percent decrease).
Paul Loprinzi, an assistant professor at Bellarmine University is lead author of the study, which was conducted while he was a doctoral student in Cardinal's lab at OSU. He said it is the first study to examine the relationship between accelerometer-measured physical activity and sleep while utilizing a nationally representative sample of adults of all ages.
'Our findings demonstrate a link between regular physical activity and perceptions of sleepiness during the day, which suggests that participation in physical activity on a regular basis may positively influence an individual's productivity at work, or in the case of a student, influence their ability to pay attention in class," he said.
Cardinal said past studies linking physical activity and sleep used only self-reports of exercise. The danger with this is that many people tend to overestimate the amount of activity they do, he said.
He added that the take-away for consumers is to remember that exercise has a number of health benefits, and that can include helping feel alert and awake.
"Physical activity may not just be good for the waistline and heart, but it also can help you sleep," Cardinal said. "There are trade-offs. It may be easier when you are tired to skip the workout and go to sleep, but it may be beneficial for your long-term health to make the hard decision and get your exercise."
Source ; Science E News (November 2011)
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