Hormonal boost to athletic performance suspect: study

March 23rd, 2008 - 2:47 pm ICT by admin  

New York, March 23 (IANS) Athletes who risk their careers by taking banned growth hormones to improve performance may not be getting the benefits they anticipate, according to a new study by Stanford University researchers. The researchers pooled data from previous studies in an attempt to summarise what’s known about the growth hormone’s effects on athletic performance, ScienceDaily reported.

Though this analysis may not reflect the way athletes actually take the drug illicitly, it was a good time to scrutinise what was known about the drug, said Hau Liu, lead author of the study.

The International Olympic Committee (IOC) bans use of growth hormones. Despite this, athletes often take the drug to boost their strength and performance. One attraction to growth hormone as an athletic enhancer is that it is difficult to detect.

But the growth hormones may not deliver the benefits some athletes expect. “What we saw is that while there was a change in body composition, that didn’t translate to an improvement in performance,” said Liu.

Findings of the study have been published in the online version of the Annals of Internal Medicine.

The group searched medical literature as far back as 1966 looking for studies, which tested the physiological effects of excess growth hormone compared with a placebo in healthy people.

To be included, the studies had to be double-blinded - neither the participants nor the researchers could know which participants received growth hormone and which received placebo.

They excluded studies involving people with growth hormone deficits caused by pituitary tumours or other conditions. In those people, bringing growth hormone up to normal levels does improve strength.

They found 27 studies with a total of 303 participants that fit the bill. When they combined data from these independent studies looking at the effects of growth hormone in healthy people, the picture it painted wasn’t good.

Overall, people who received growth hormone did seem to have more lean body mass, which is generally associated with more muscle. However, during exercise, the people who got growth hormone in some of the studies generated more lactate - the by-product of exercise that can cause muscle fatigue.

In one study, two cyclists who received growth hormone weren’t able to finish a workout because of fatigue.

Also, despite having leaner body mass, people didn’t appear to be any stronger after receiving the drug. Studies examining other measures of athletic performance also revealed no improvement.

“The key takeaway is that we don’t have any good scientific evidence that growth hormone improves athletic performance,” said co-author Andrew Hoffman.

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