Wednesday, September 3, 2014

Over-hydrating can be lethal, though it rarely happens


Newswise — MAYWOOD, Ill. (Sept. 2, 2014) – The recent deaths of two high school football players illustrate the dangers of drinking too much water and sports drinks, according to Loyola University Medical Center sports medicine physician Dr. James Winger.
Over-hydration by athletes is called exercise-associated hyponatremia. It occurs when athletes drink even when they are not thirsty. Drinking too much during exercise can overwhelm the body’s ability to remove water. The sodium content of blood is diluted to abnormally low levels. Cells absorb excess water, which can cause swelling — most dangerously in the brain.
Hyponatremia can cause muscle cramps, nausea, vomiting, seizures, unconsciousness, and, in rare cases, death.
Georgia football player Zyrees Oliver reportedly drank 2 gallons of water and 2 gallons of a sports drink. He collapsed at home after football practice, and died later at a hospital. In Mississippi, Walker Wilbank was taken to the hospital during the second half of a game after vomiting and complaining of a leg cramp. He had a seizure in the emergency room and later died. A doctor confirmed he had exercise-associated hyponatremia.
And in recent years, there have been more than a dozen documented and suspected runners’ deaths from hyponatremia.
Winger said it’s common for coaches to encourage athletes to drink profusely, before they get thirsty. But he noted that expert guidelines recommend athletes drink only when thirsty. Winger said athletes should not drink a predetermined amount, or try to get ahead of their thirst.
Drinking only when thirsty can cause mild dehydration. “However, the risks associated with dehydration are small,” Winger said. “No one has died on sports fields from dehydration, and the adverse effects of mild dehydration are questionable. But athletes, on rare occasions, have died from over-hydration.”
Winger is co-author of a 2011 study that found that nearly half of Chicago-area recreational runners surveyed may be drinking too much fluid during races. Winger and colleagues found that, contrary to expert guidelines, 36.5 percent of runners drink according to a present schedule or to maintain a certain body weight and 8.9 percent drink as much as possible.
“Many athletes hold unscientific views regarding the benefits of different hydration practices,” Winger and colleagues concluded. Their study was published in the British Journal of Sports Medicine.
Winger is an associate professor in the Department of Family Medicine of Loyola University Chicago Stritch School of Medicine.
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Do you heel strike or are you a forefoot runner?


If you have no idea what that question means this wearable probably isn’t for you. RunScribe is aiming for serious running geeks who want to nerd out over exactly how, where and when their feet connect with the ground — and use that data to improve their running technique and (hopefully) avoid injury.
Running has been a popular target for fitness focused wearables up to now, with fitness bands and running-focused smartwatches mushrooming forth as forerunners of the nascent wearables category. But as more and more generic fitness bands crop up, an appetite for greater specialism is likely to gather momentum.  So enter RunScribe: a device that attaches to the back of your running shoe in order to be well-placed to figure out exactly how you are running.
The data its motion sensors capture is stored locally on flash memory during each run and synced to a cloud service after — visualised via various granular charts and graphs — allowing the athlete to do a deep data dive analysis of their gait. (A top tier of the service — called runScribe Science — will even give the user access to the raw sensor data captured by the device.)
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Friday, August 22, 2014

Green tea polyphenols protect spinal cord neurons against oxidative stress


Green tea polyphenols are strong antioxidants and can reduce free radical damage. Can they protect spinal cord neurons against oxidative stress? Jianbo Zhao and co-workers from the First Affiliated Hospital of Liaoning Medical University, China discovered that green tea polyphenol effectively alleviated oxidative stress and inhibit neuronal apoptosis, indicating green tea polyphenols play a protective role in spinal cord neurons under oxidative stress. The relevant study has been published in the Neural Regeneration Research (Vol. 9, No. 14, 2014).


Article: “Green tea polyphenols protect spinal cord neurons against hydrogen peroxide-induced oxidative stress,” by Jianbo Zhao , Shiqiang Fang , Yajiang Yuan , Zhanpeng Guo , Jinhao Zeng , Yue Guo , Peifu Tang , Xifan Mei (1 Vertebral Column Ward, Department of Orthopedics, First Affliated Hospital of Liaoning Medical University, Jinzhou, Liaoning Province, China;2 Department of Orthopedics, General Hospital of People’s Liberation Army, Beijing, China)
Zhao JB, Fang SQ, Yuan YJ, Guo ZP, Zeng JH, Guo Y, Tang PF , Mei XF. Green tea polyphenols protect spinal cord neurons against hydrogen peroxide-induced oxidative stress. Neural Regen Res. 2014;9(14):1379-1385
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Thursday, August 21, 2014

‘Combining caffeine with exercise creates a greater energy deficit’: Journal of Applied Physiology



J Appl Physiol (1985). 2014 Aug 14. pii: jap.00570.2014. [Epub ahead of print]
Caffeine consumption around an exercise bout: effects on energy expenditure, energy intake, and exercise enjoyment.
Schubert MM1, Hall S2, Leveritt M3, Grant G2, Sabapathy S2, Desbrow B2.
Author information
1Griffith University
2Griffith University.
3The University of Queensland.
Combining an exercise and nutritional intervention is arguably the optimal method of creating energy imbalance for weight loss.
This study sought to determine if combining exercise and caffeine supplementation was more effective for promoting acute energy deficits and manipulations to substrate metabolism than exercise alone.
Fourteen recreationally-active participants (Mean ± SD BMI: 22.7 ± 2.6 kg∙m-2) completed a resting control trial (CON), a placebo exercise trial (EX), and a caffeine exercise trial (EX+CAF, 2x 3 mg∙kg-1 of caffeine 90 min before and 30 min after exercise) in a randomized, double-blinded design.
Trials were 4 h in duration with 1 h of rest, 1 h of cycling at ~65 % power at VO2max or rest, and a 2 h recovery.
Gas exchange, appetite perceptions, and blood samples were obtained periodically.
Two hours after exercise, participants were offered an ad libitum test meal where energy and macronutrient intake were recorded.
EX+CAF resulted in significantly greater energy expenditure and fat oxidation compared to EX (+250 kJ; +10.4 g) and CON (+3126 kJ; +29.7 g) (P < 0.05).
A trend for reduced energy and fat intake compared to CON (-718 kJ; -8 g) (P = 0.055) was observed.
Consequently, EX+CAF created a greater energy deficit (P < 0.05).
Caffeine also led to exercise being perceived as less difficult and more enjoyable (P < 0.05).
Combining caffeine with exercise creates a greater energy deficit and the implications of this protocol for weight loss or maintenance over longer time periods in overweight/obese populations require further investigation.
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Low back pain and exercise in children and adolescents

Posted on August 17, 2014 by Stone Hearth News

Eur Spine J. 2014 Jul 29. [Epub ahead of print]

Low back pain in children and adolescents: a systematic review and meta-analysis evaluating the effectiveness of conservative interventions.

Michaleff ZA1, Kamper SJ, Maher CG, Evans R, Broderick C, Henschke N.

Author information

1The George Institute for Global Health and Sydney Medical School, The University of Sydney, Kent Street, Sydney, 2000, Australia,



To identify and evaluate the effectiveness of conservative treatment approaches used in children and adolescents to manage and prevent low back pain (LBP).


Five electronic databases and the reference lists of systematic reviews were searched for relevant studies. Randomised controlled trials (RCTs) were considered eligible for inclusion if they enrolled a sample of children or adolescents


Four RCTs on intervention and eleven RCTs on prevention of LBP were included. All included studies had a high risk of bias scoring ≤7 on the PEDro scale. For the treatment of LBP, a supervised exercise program compared to no treatment improved the average pain intensity over the past month by 2.9 points (95 % CI 1.6-4.1) measured by a 0-10 scale (2 studies; n = 125). For the prevention of LBP, there was moderate quality evidence to suggest back education and promotion programs are not effective in reducing LBP prevalence in children and adolescents.


While exercise interventions appear to be promising to treat LBP in children and adolescents, there is a dearth of research data relevant to paediatric populations. Future studies conducted in children and adolescents with LBP should incorporate what has been learnt from adult LBP research and be of rigorous methodological quality.


Hatha yoga boosts brain function in older adults: University of Illinois at Urbana-Champaign

Posted on August 18, 2014 by Stone Hearth News

CHAMPAIGN, Ill. — Practicing hatha yoga three times a week for eight weeks improved sedentary older adults’ performance on cognitive tasks that are relevant to everyday life, researchers report.

The findings involved 108 adults between the ages of 55 and 79 years of age, 61 of whom attended hatha yoga classes. The others met for the same number and length of sessions and engaged in stretching and toning exercises instead of yoga.

At the end of the eight weeks, the yoga group was speedier and more accurate on tests of information recall, mental flexibility and task-switching than it had been before the intervention. The stretching-and-toning group saw no significant change in cognitive performance over time. The differences seen between the groups were not the result of differences in age, gender, social status or other demographic factors, the research team reported.

Hatha yoga is an ancient spiritual practice that involves meditation and focused breathing while an individual moves through a series of stylized postures, said Neha Gothe, who led the study with University of Illinois kinesiology and community health professor Edward McAuley. Beckman Institute director Arthur Kramer also contributed to the study. Gothe is now a professor at Wayne State University.

“Hatha yoga requires focused effort in moving through the poses, controlling the body and breathing at a steady rate,” Gothe said. “It is possible that this focus on one’s body, mind and breath during yoga practice may have generalized to situations outside of the yoga classes, resulting in an improved ability to sustain attention.”

“Participants in the yoga intervention group showed significant improvements in working memory capacity, which involves continually updating and manipulating information,” McAuley said. “They were also able to perform the task at hand quickly and accurately, without getting distracted. These mental functions are relevant to our everyday functioning, as we multitask and plan our day-to-day activities.”

Previous studies have found that yoga can have immediate positive psychological effects by decreasing anxiety, depression and stress, Gothe said.

“These studies suggest that yoga has an immediate quieting effect on the sympathetic nervous system and on the body’s response to stress,” she said. “Since we know that stress and anxiety can affect cognitive performance, the eight-week yoga intervention may have boosted participants’ performance by reducing their stress.”

The results of the study are only preliminary and involve a fairly short-term intervention, the researchers said. Further research is needed to confirm the results and reveal the underlying brain mechanisms at play.

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The efficacy of nitrate supplementation in altering the physiological determinants of sport and exercise performance

 Posted on August 17, 2014 by Stone Hearth News

 Appl Physiol Nutr Metab. 2014 Apr 30:1-10.

Influence of dietary nitrate on the physiological determinants of exercise performance: a critical review.

 Jones AM.

Author information

 Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke’s Campus, University of Exeter, Heavitree Road, Exeter, EX1 2LU, UK.


Dietary nitrate supplementation, usually in the form of beetroot juice, has been heralded as a possible new ergogenic aid for sport and exercise performance.

Early studies in recreationally active participants indicated that nitrate ingestion significantly reduces the O2 cost of submaximal exercise and improves performance during high-intensity endurance exercise.

Subsequent studies have begun to address the physiological mechanisms underpinning these observations and to investigate the human populations in whom, and the exercise conditions (high- vs. low-intensity, long- vs. short-duration, continuous vs. intermittent, normoxic vs. hypoxic) under which, nitrate supplementation may be beneficial.

Moreover, the optimal nitrate loading regimen in terms of nitrate dose and duration of supplementation has been explored.

Depending on these factors, nitrate supplementation has been shown to exert physiological effects that could be conducive to exercise performance enhancement, at least in recreationally active or sub-élite athletes.

This article provides a “state-of-the-art” review of the literature pertinent to the evaluation of the efficacy of nitrate supplementation in altering the physiological determinants of sport and exercise performance.

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