Posts Tagged ‘Athlete’

UK researchers believe that eating watercress may alleviate the oxidative stress that comes with heavy bouts of exercise.   Watercress contains an array of nutritional compounds such as β-carotene and α-tocopherol which may increase protection against exercise-induced oxidative stress. The leafy green vegetable was the focus of a recent study published in the British Journal of Nutrition.

Ten healthy males were assigned to eight weeks of watercress consumption followed by eight weeks of control (no watercress). Blood samples were analyzed for DNA damage and lipid peroxidation at baseline (before supplementation), at rest (before exercise), and following exercise.

Exercise resulted in an increase in DNA damage and lipid peroxidation when subjects took part in the control phase of the study, but when watercress was added to the diet, markers of DNA damage and lipid peroxidation were significantly reduced. Even acute supplementation improved DNA and lipid protection, suggesting that only small amounts of the leafy green were needed to reduce oxidative stress in the body.

Blood analysis revealed notable increases of xanthophylls, alpha-tocopherol, and gamma-tocopherol with watercress consumption. The researchers proposed that these compounds might have a role in increased protection against oxidative stress.

The main findings show an exercise-induced increase in DNA damage and lipid peroxidation over both acute and chronic control supplementation phases (< 0·05 v. supplementation), while acute and chronic watercress attenuated DNA damage and lipid peroxidation and decreased H2O2 accumulation following exhaustive exercise (P < 0·05 v. supplementation), while acute and chronic watercress attenuated DNA damage and lipid peroxidation and decreased H2O2 accumulation following exhaustive exercise (P < 0·05 v. control). A marked increase in the main lipid-soluble antioxidants (α-tocopherol, γ-tocopherol and xanthophyll) was observed following watercress supplementation (P < 0·05 v. control) in both experimental phases. These findings suggest that short- and long-term watercress ingestion has potential antioxidant effects against exercise-induced DNA damage and lipid peroxidation.

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Researchers at The University of Auckland have shown for the first time that the mere presence of carbohydrate solution in the mouth immediately boosts muscle strength, even before it is swallowed.

The results suggest that a previously unknown neural pathway is activated when receptors in the mouth detect carbohydrate, stimulating parts of the brain that control muscle activity and producing an increase in muscle strength.

Previous research had shown that the presence of carbohydrate in the mouth can improve physical performance during prolonged activity, but the mechanism involved was not known and it was unclear whether a person must be fatigued for the effect to be seen.

“There appears to be a pathway in the brain that tells our muscles when energy is on the way,” says lead researcher Dr Nicholas Gant from the Department of Sport and Exercise Science.

“We have shown that carbohydrate in the mouth produces an immediate increase in neural drive to both fresh and fatigued muscle and that the size of the effect is unrelated to the amount of glucose in the blood or the extent of fatigue.”

The current research has been published in the journal Brain Research and has also captured the attention of New Scientist magazine.

In the first of two experiments, 16 healthy young men who had been doing biceps exercises for 11 minutes were given a carbohydrate solution to drink or an identically flavored energy-free placebo. Their biceps strength was measured before and immediately afterward, as was the activity of the brain pathway known to supply the biceps.

Around one second after swallowing the drink, neural activity increased by 30 percent and muscle strength two percent, with the effect lasting for around three minutes. The response was not related to the amount of glucose in the bloodstream or how fatigued the participants were.

“It might not sound like much, but a two percent increase in muscle strength is enormous, especially at the elite level. It’s the difference between winning an Olympic medal or not,” says co-author Dr Cathy Stinear.

As might be expected, a second boost in muscle strength was observed after 10 minutes when carbohydrate reached the bloodstream and muscles through digestion, but no additional boost in neural activity was seen at that time.

“Two quite distinct mechanisms are involved,” says Dr Stinear. “The first is the signal from the mouth via the brain that energy is about to be available and the second is when the carbohydrate actually reaches the muscles and provides that energy,” says Dr Stinear.

“The carbohydrate and placebo solutions used in the experiment were of identical flavor and sweetness, confirming that receptors in the mouth can process other sensory information aside from the basic taste qualities of food. The results suggest that detecting energy may be a sixth taste sense in humans,” says Dr Gant.

In the second experiment, 17 participants who had not been doing exercise and were not fatigued simply held one of the solutions in their mouths without swallowing. Measurements of the muscle between the thumb and index finger were taken while the muscle was either relaxed or active.

A similar, though smaller effect was observed as in the first experiment, with a nine percent increase in neural activity produced by the carbohydrate solution compared with placebo. This showed that the response is seen in both large powerful muscles and in smaller muscles responsible for fine hand movements.

“Together the results show that carbohydrate in the mouth activates the neural pathway whether or not muscles are fatigued. We were surprised by this, because we had expected that the response would be part of the brain’s sophisticated system for monitoring energy levels during exercise,” says Dr Stinear.

“Seeing the same effect in fresh muscle suggests that it’s more of a simple reflex – part of our basic wiring – and it appears that very ancient parts of the brain such as the brainstem are involved. Reflexive movements in response to touch, vision and hearing are well known but this is the first time that a reflex linking taste and muscle activity has been described,” she says.

Further research is required to determine the precise mechanisms involved and to learn more about the size of the effect on fresh versus fatigued muscle.

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Article adapted by MD Sports from original press release.
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Contact: Pauline Curtis
The University of Auckland

A Temple University researcher seeking physiological evidence of chronic fatigue syndrome (CFS) has found a link between creatine and metabolic energy. The findings, which hold promise for future CFS treatments, were published in a recent issue of the Journal of Applied Physiology.

“We found that creatine affects mitochondria – the parts of the cells that produce energy for all biological functioning – in normal human subjects. Now that we have established this baseline evidence, we are looking at the link between creatine and energy production in CFS patients,” said lead author Sinclair Smith, Sc.D., assistant professor of occupational therapy in Temple’s College of Health Professions.

Creatine, thought to build muscle and improve performance, is a popular over-the-counter supplement used by athletes. Smith and his colleagues wondered if creatine could also be used to help relieve the extreme physical and mental fatigue that strikes CFS sufferers. “Many physicians still don’t believe that CFS exists, making it important to investigate possible physiologic differences and to determine if we can impact metabolic function in CFS patients,” explained Smith.

“In addition to improving muscle metabolic function, recent studies show that creatine supplementation may improve nervous system function as well. Given that cognitive fatigue is a frequent symptom of CFS, we thought that creatine may enhance both muscle and neural metabolic status in people with CFS,” said Smith.

In the study, “Use of phosphocreatine kinetics to determine the influence of creatine on muscle mitochondrial respiration: an in vivo 31P-MRS study of oral creatine ingestion,” the researchers analyzed the effect of naturally -produced and supplemental creatine on the rate of muscle metabolism using non-invasive magnetic resonance imaging (MRI) techniques during exercise and rest.

While previous studies have evaluated the link between creatine and mitochondria in animals and human muscle samples, Smith’s was the first lab to test in people.

Smith collaborated in this research with the U.S. Army Research Institute of Environmental Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston University and Sargent College of Health and Rehabilitation Sciences.

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    Article adapted by MD Sports from original press release.
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WESTCHESTER, Ill. – Athletes who get an extra amount of sleep are more likely to improve their performance in a game, according to a research abstract presented at the 21st Annual Meeting of the Associated Professional Sleep Societies (APSS).

The study, authored by Cheri Mah of Stanford University, was conducted on six healthy students on the Stanford men’s basketball team, who maintained their typical sleep-wake patterns for a two-week baseline followed by an extended sleep period in which they obtained as much extra sleep as possible. To assess improvements in athletic performance, the students were judged based on their sprint time and shooting percentages.

Significant improvements in athletic performance were observed, including faster sprint time and increased free-throws. Athletes also reported increased energy and improved mood during practices and games, as well as a decreased level of fatigue.

“Although much research has established the detrimental effects of sleep deprivation on cognitive function, mood and performance, relatively little research has investigated the effects of extra sleep over multiple nights on these variables, and even less on the specific relationship between extra sleep and athletic performance. This study illuminated this latter relationship and showed that obtaining extra sleep was associated with improvements in indicators of athletic performance and mood among members of the men’s basketball team.”

The amount of sleep a person gets affects his or her physical health, emotional well-being, mental abilities, productivity and performance. Recent studies associate lack of sleep with serious health problems such as an increased risk of depression, obesity, cardiovascular disease and diabetes.
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Article adapted by MD Sports from original press release.
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Contact: Jim Arcuri
American Academy of Sleep Medicine 

Experts recommend that adults get between seven and eight hours of sleep each night to maintain good health and optimum performance.

Persons who think they might be suffering from a sleep disorder are encouraged to consult with their primary care physician, who will refer them to a sleep specialist.

The annual SLEEP meeting brings together an international body of 5,000 leading researchers and clinicians in the field of sleep medicine to present and discuss new findings and medical developments related to sleep and sleep disorders.

More than 1,000 research abstracts will be presented at the SLEEP meeting, a joint venture of the American Academy of Sleep Medicine and the Sleep Research Society. The four-day scientific meeting will bring to light new findings that enhance the understanding of the processes of sleep and aid the diagnosis and treatment of sleep disorders such as insomnia, narcolepsy and sleep apnea.

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Research News

Negative Energy Balance

By Sandco Staff

University Park, Pa. – Female athletes often lose their menstrual cycle when training strenuously, but researchers have long speculated on whether this infertility was due to low body fat, low weight or exercise itself. Now, researchers have shown that the cause of athletic amenorrhea is more likely a negative energy balance caused by increasing exercise without increasing food intake.

“A growing proportion of women are susceptible to losing their menstrual cycle when exercising strenuously,” says Dr. Nancy I. Williams, assistant professor of kineseology and physiology at Penn State. “If women go six to 12 months without having a menstrual cycle, they could show bone loss. Bone densities in some long distance runners who have gone for a prolonged time period without having normal menstrual cycles can be very low.”

In studies done with monkeys, which show menstrual cyclicity much like women, researchers showed that low energy availability associated with strenuous exercise training plays an important role in causing exercise-induced amenorrhea. These researchers, working at the University of Pittsburgh, published findings in the Journal of Clinical Endocrinology and Metabolism showing that exercise-induced amenorrhea was reversible in the monkeys by increasing food intake while the monkeys still exercised.

Williams worked with Judy L. Cameron, associate professor of psychiatry and cell biology and physiology at the University of Pittsburgh. Dana L. Helmreich and David B. Parfitt, then graduate students, and Anne Caston-Balderrama, at that time a post-doctoral fellow at the University of Pittsburgh, were also part of the research team. The researchers decided to look at an animal model to understand the causes of exercise-induced amenorrhea because it is difficult to closely control factors, such as eating habits and exercise, when studying humans. They chose cynomolgus monkeys because, like humans, they have a menstrual cycle of 28 days, ovulate in mid-cycle and show monthly periods of menses.

“It is difficult to obtain rigorous control in human studies, short of locking people up,” says Williams.

Previous cross-sectional studies and short-term studies in humans had shown a correlation between changes in energy availability and changes in the menstrual cycle, but those studies were not definitive.

There was also some indication that metabolic states experienced by strenuously exercising women were similar to those in chronically calorie restricted people. However, whether the increased energy utilization which occurs with exercise or some other effect of exercise caused exercise-induced reproductive dysfunction was unknown.

“The idea that exercise or something about exercise is harmful to females was not definitively ruled out,” says Williams. “That exercise itself is harmful would be a dangerous message to put out there. We needed to look at what it was about exercise that caused amenorrhea, what it was that suppresses ovulation. To do that, we needed a carefully controlled study.”

After the researchers monitored normal menstrual cycles in eight monkeys for a few months, they trained the monkeys to run on treadmills, slowly increasing their daily training schedule to about six miles per day. Throughout the training period the amount of food provided remained the standard amount for a normal 4.5 to 7.5 pound monkey, although the researchers note that some monkeys did not finish all of their food all of the time.

The researchers found that during the study “there were no significant changes in body weight or caloric intake over the course of training and the development of amenorrhea.” While body weight did not change, there were indications of an adaptation in energy expenditure. That is, the monkeys’ metabolic hormones also changed, with a 20 percent drop in circulating thyroid hormone, suggesting that the suppression of ovulation is more closely related to negative energy balance than to a decrease in body weight.

To seal the conclusion that a negative energy balance was the key to exercise-induced amenorrhea, the researchers took four of the previous eight monkeys and, while keeping them on the same exercise program, provided them with more food than they were used to. All the monkeys eventually resumed normal menstrual cycles. However, those monkeys who increased their food consumption most rapidly and consumed the most additional food, resumed ovulation within as little as 12 to 16 days while those who increased their caloric intake more slowly, took almost two months to resume ovulation.

Williams is now conducting studies on women who agree to exercise and eat according to a prescribed regimen for four to six months. She is concerned because recreational exercisers have the first signs of ovulatory suppression and may easily be thrust into amenorrhea if energy availability declines. Many women that exercise also restrict their calories, consciously or unconsciously.

“Our goal is to test whether practical guidelines can be developed regarding the optimal balance between calories of food taken in and calories expended through exercise in order to maintain ovulation and regular menstrual cycles,” says Williams. “This would then ensure that estrogen levels were also maintained at healthy levels. This is important because estrogen is a key hormone in the body for many physiological systems, influencing bone strength and cardiovascular health, not just reproduction.”

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Article adapted by MD Sports from original press release.
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Contact: A’ndrea Elyse Messer
Penn State

Genetic research into athletic ability should be encouraged for its potential benefits in both sport and public health, a leading group of scientists meeting at the University of Bath said today.

Genetic research into athletic ability should be encouraged for its potential benefits in both sport and public health, a leading group of scientists meeting at the University of Bath said today.

However, ethical concerns, such as whether seeking information about differences between ethnic groups could be perceived as racist research, need to be properly addressed, they warn.

Their recommendations are published in a ‘position stand’ on genetic research and testing launched at the British Association of Sport & Exercise Sciences annual meeting today.

They call for more genetic research in the sport and exercise sciences because of the anticipated benefits for public health, but want researchers to take a more active role in debating the implications of their work with the public.

“If a powerful muscle growth gene was identified, on the one hand this could help develop training programmes that increase muscle size and strength in athletes, but even more importantly the knowledge could be used to develop exercise programmes or drugs to combat muscle wasting in old age,” said Dr Alun Williams from Manchester Metropolitan University, one of the report’s authors.

“We, as scientists investigating genetics, acknowledge a public concern about some genetic research and we believe scientists need to engage in public in debates about the potential benefits of their research.

“Research into the athletic success of East African distance runners or sprinters of West African ancestry might be perceived as unethical.

“But understanding the limits of human exercise capacity in sport could lead to the development of treatments for a range of diseases like cancer and cardiovascular disease.”

The potential applications of genetic testing in sport and exercise also raise some ethical concerns, for example in identifying potential athletic ability before birth.

An Australian company already offers the first genetic performance test (for the ACTN3 gene) which has been linked to sprint and power performance.

The report authors are sceptical about whether this test is useful but anticipate that more advanced versions of these tests will be available in future.

“We are not yet at a point where we can identify a potential future Olympic champion from genetic tests but we may not be very far away,” said Dr Williams, who wrote the report with Drs Henning Wackerhage (Aberdeen University), Andy Miah (University of Paisley), Roger Harris (University of Chichester) and Hugh Montgomery (University College London).

They highlight two dangers of genetic performance tests. Firstly, genetic performance tests might later be linked to disease. For example, a muscle growth gene may later be linked to cancer growth.

“Not all people may want to know, while young that they are at increased risk of cancer by early middle age, but they might inadvertently become aware of that just because they had a ‘sport gene’ test,” said Dr Williams.

Secondly, genetic performance tests can be performed even before birth and this may lead to the selection of foetuses or to abortions based on athletic potential.

The report recommends genetic counselling and that the testing should be confined to mature individuals who fully understand the relevant issues.

Genetic tests might also be used to screen for health risks during sport such as genes that are linked to sudden cardiac death.

Genetic tests for sudden cardiac death are already available but the report recommends that such testing should not be enforced on athletes.

Problems with mandatory testing are highlighted by the case of the basketball player Eddy Curry, who had an irregular heart beat.

Curry was asked by his club, the Chicago Bulls, to perform a predictive genetic test for a heart condition. The athlete refused and was traded to the New York Knicks who did not make such a demand.

In future, genetic tests might be used to identify those that respond with the biggest drop in cholesterol, blood pressure or glucose to exercise.

In a personalised medicine approach, such tests could be used to select subjects for therapeutic exercise programmes but scientists are concerned that this might undermine the ‘exercise for all’ message that already seems difficult to get across to the public.

The authors say that genetic testing might also be used to detect gene doping, which may be a real threat by the time of the London Olympics in 2012, or to show that positive doping tests are the result of a genetic mutation in an athlete.

The report recommends that genetic testing should be used for anti-doping testing as long as the genetic samples are destroyed after testing.

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Article adapted by MD Sports from original press release.
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Contact: Andrew McLaughlin
University of Bath