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General interest items edited by Janice Flahiff

[Press release] eScienceCommons: Athletes’ testosterone surges not tied to winning, study finds

eScienceCommons: Athletes’ testosterone surges not tied to winning, study finds.
From the press release

Friday, November 21, 2014

Athletes’ testosterone surges not tied to winning, study finds

Kathleen Casto, number 1931 in the center, shown competing in cross country as an undergraduate in North Carolina. She is now a graduate student in psychology at Emory, studying the hormonal correlates of competition in women.

By Carol Clark

A higher surge of testosterone in competition, the so-called “winner effect,” is not actually related to winning, suggests a new study of intercollegiate cross country runners.

The International Journal of Exercise Science published the research, led byDavid Edwards, a professor of psychology at Emory University, and his graduate student Kathleen Casto.

“Many people in the scientific literature and in popular culture link testosterone increases to winning,” Casto says. “In this study, however, we found an increase in testosterone during a race regardless of the athletes’ finish time. In fact, one of the runners with the highest increases in testosterone finished with one of the slowest times.”

The study, which analyzed saliva samples of participants, also showed that testosterone levels rise in athletes during the warm-up period. “It’s surprising that not only does competition itself, irrespective of outcome, substantially increase testosterone, but also that testosterone begins to increase before the competition even begins, long before status of winner or loser are determined,” Casto says.

November 28, 2014 Posted by | Medical and Health Research News | , , , , , | Leave a comment

Study Finds Declining Testosterone Levels In Men Not Part Of Normal Aging

From the 25 June 2012 Medical News Today article

A new study finds that a drop in testosterone levels over time is more likely to result from a man’s behavioral and health changes than by aging. The study results will be presented Monday at The Endocrine Society’s 94th Annual Meeting in Houston.

“Declining testosterone levels are not an inevitable part of the aging process, as many people think,” said study co-author Gary Wittert, MD, professor of medicine at the University of Adelaide in Adelaide, Australia. “Testosterone changes are largely explained by smoking behavior and changes in health status, particularly obesityand depression.” …

June 25, 2012 Posted by | Consumer Health | , , | Leave a comment

Research debunks bodybuilding myth: Growth-promoting hormones don’t stimulate strength

Muscles!

Muscles! (Photo credit: Unlisted Sightings)

From the 14 June 2012 EurekAlert

New research from scientists at McMaster University reveals exercise-related testosterone and growth hormone do not play an influential role in building muscle after weightlifting, despite conventional wisdom suggesting otherwise.

The findings indicate that bodybuilders who look to manipulate those hormones through exercise routines are wasting their time.

In two separate studies, published in the Journal of Applied Physiology and the European Journal of Applied Physiology, researchers found anabolic hormones—long thought to be essential for building a muscular frame—do not influence muscle protein synthesis, the process that leads to bigger muscles.

“A popular mindset for weightlifters is that increased levels of hormones after exercise play a key role in building muscle,” explains Daniel West, lead author of both studies and a graduate student in the Department of Kinesiology at McMaster. “That is simply not the case.”

In the first study, researchers examined the responses of both male and female participants to intense leg exercise. Despite a 45-fold difference in testosterone increase, men and women were able to make new muscle protein at exactly the same rate.

“Since new muscle proteins eventually add up to muscle growth, this is an important finding,” says West.

“While testosterone is definitely anabolic and promotes muscle growth in men and women at high doses, such as those used during steroid abuse, our findings show that naturally occurring levels of testosterone do not influence the rate of muscle protein synthesis.”

In the second study, researchers analyzed the post-exercise hormonal responses of 56 young men, aged 18 to 30, who trained five days a week for 12 weeks in total.

The men experienced gains in muscle mass that ranged from virtually nothing to more than 12 pounds, yet their levels of testosterone and growth hormone after exercise showed no relationship to muscle growth or strength gain.

Surprisingly, the researchers noted that cortisol—considered to have the opposite effect of anabolic hormones because it reduces protein synthesis and breaks down tissue—was related to the gain in muscle mass.

“The idea that you can or should base entire exercise training programs on trying to manipulate testosterone or growth hormone levels is false,” says Stuart Phillips, a professor in the Department of Kinesiology. “There is simply no evidence to support this concept.”

 

June 15, 2012 Posted by | Medical and Health Research News | , , , , , , | Leave a comment

Parents’ social problems affect their children — even in birds

Parents’ social problems affect their children — even in birds

From the December 27, 2010 Eureka news alert

It may come as a surprise to many that quails are able to distinguish one another, let alone that they form close relationships with other quails. Nevertheless, it has long been known that disruption of the birds’ social environment causes them stress. A group within the UMR 6552 at the CNRS-Université de Rennes 1 in France has been studying the influence of adults on the behavioural development of their offspring. Together with scientists in Austria, they have now shown that changing the composition of groups of quails housed together causes the birds to behave more aggressively towards one another. In parallel, the level of steroid hormones (corticosterone) in their blood increases when their group composition is disrupted.

Intriguingly, the eggs they lay were found to have significantly higher levels of testosterone when the mothers were subjected to social stress of this kind. The results are consistent with previous findings from other groups, which showed that House sparrows, American coots and Common starlings lay eggs with more testosterone when they breed in dense colonies than when they nest in isolation. But the new work from the French-Austrian collaboration goes considerably further, showing that the eggs of females under social stress hatch later and the chicks grow more slowly after hatching, at least for the first three weeks. There are also indications that the chicks’ behave differently: they are more cautious and seem more susceptible to disturbance. Furthermore, they tend to move about more, which can be interpreted as increased attempts to escape from threats or to seek more social contact.

The results show how much the growth and behaviour of chicks is influenced by the concentrations of steroid hormones in the eggs from which they hatched. As Möstl says, “We know that stress on female mammals influences the development of their young, which takes place in the womb, but it was a big surprise that social stress causes such changes in the level of hormones in the yolks of birds’ eggs.” The social environment of mother quails thus has a direct effect on the growth and the behaviour of their offspring. It seems, then, that pre-natal nurture is extremely important in birds as well as in mammals and this finding is sure to add fresh fuel to the century-old nature versus nurture debate.

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The paper Social Instability in Laying Quail: Consequences on Yolk Steroids and Offspring’s Phenotype by Floriane Guibert, Marie-Annick Richard-Yris, Sophie Lumineau, Kurt Kotrschal, Daniel Guémené, Aline Bertin, Erich Möstl and Cécilia Houdelier was published in November by PLoS ONE (10.1371/journal.pone.0014069).

December 28, 2010 Posted by | Medical and Health Research News | , , , , , , | Leave a comment

   

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