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Growth hormone no benefit to athletes: U.S. study
WASHINGTON (Reuters) - People who take human growth hormone in the hope of boosting athletic performance are not only breaking the law and risking their health, but likely are not even achieving their objective, U.S. researchers reported on Monday.
While some reports show that some illegal steroids may help athletes bulk up and train harder, human growth hormone is not one of them, the report in the Annals of Internal Medicine suggests.
\"What we saw is that while there was a change in body composition, we didn't find evidence that growth hormone improves athletic performance,\" Dr. Hau Liu of Stanford University in California, who led the study, said in a telephone interview.
Liu's team looked at 27 studies covering 303 people aged 13 to 45. They found that, overall, those who took growth hormone did develop more lean body mass, but this did not translate to either more strength or exercise capacity.
People who took growth hormone had swelling of their tissues and more fatigue compared to people not taking the drug, they added.
Use of growth hormone is banned by the International Olympic Committee, Major League Baseball and the National Football League. U.S. law prohibits its use for sports enhancement.
When the hormone is given to people with growth hormone deficits caused by pituitary tumors or other conditions, it can improve strength. But it does not enhance strength in normal, healthy people.
For example, people given hormone generated more lactate, a byproduct of exercise that can cause pain and muscle fatigue. In one study meant to see if human growth hormone might boost strength or endurance, two cyclists given the hormone stopped a workout because of fatigue.
\"The key takeaway is that we don't have any good scientific evidence that growth hormone improves athletic performance,\" Dr. Andrew Hoffman, a professor of endocrinology, gerontology and metabolism who worked on the study, said.
Hoffman noted that other hormones have been shown to benefit athletes -- notably testosterone.
\"Athletes probably take much more hormone than the investigators felt that they could ethically try to give to healthy people; in addition, some athletes combine growth hormone with other anabolic hormones like testosterone,\" Hoffman added in an e-mail.
Hoffman said people get side-effects from high doses of hormones. \"You get fluid accumulating in the legs, you get pain in the joints,\" he said in a telephone interview.
\"From what we hear the athletes are taking very, very large doses,\" he added.
Other hormones do, however bulk up athletes -- although not without risk, Hoffman said. \"The findings with growth hormone absolutely do not extend to other hormones like testosterone which work through entirely different mechanisms,\" he said.
\"The key takeaway is that we don't have any good scientific evidence that growth hormone improves athletic performance,\" Dr. Andrew Hoffman, a professor of endocrinology, gerontology and metabolism who worked on the study, said.
Hoffman noted that other hormones have been shown to benefit athletes -- notably testosterone.
\"Athletes probably take much more hormone than the investigators felt that they could ethically try to give to healthy people; in addition, some athletes combine growth hormone with other anabolic hormones like testosterone,\" Hoffman added in an e-mail.
Hoffman said people get side-effects from high doses of hormones. \"You get fluid accumulating in the legs, you get pain in the joints,\" he said in a telephone interview.
\"From what we hear the athletes are taking very, very large doses,\" he added.
Other hormones do, however bulk up athletes -- although not without risk, Hoffman said. \"The findings with growth hormone absolutely do not extend to other hormones like testosterone which work through entirely different mechanisms,\" he said.
华盛顿(路透社)-运动员通过服用生长激素增强运动能力的想法,不但触犯了法律和危害自身健康,而且,美国研究人员在星期一的报告中称,这并不能达到你所要的目标.
在一些报告中称,某些违禁类固醇可以帮运动员快速增强运动能力且能更加刻苦的训练,报道在内科年鉴中并未称生长激素是其中之一.
加州斯坦福大学(Hau Liu )刘医生说:\"我们看到的只是身体结构的一些变化,而并没有找到生长激素可以提高运动能力的证据.\"
刘的团队观测了共303名年龄从13到45岁的27项研究.他们发现,总体上,在身体瘦小的人中生长激素有效,但是它不改变人的力量或者说运动能力.
他们补充说,用生长激素可以使组织水肿,与没有用的人相比,他们更加虚弱.
使用生长激素是被国际奥林匹克、大部分国家棒球联盟与橄榄球联盟禁止。美国法律禁止其作为运动增强剂使用。
当生长激素用于因脑垂体肿瘤及其它情况下的生长激素有缺陷的人时，它可以提高能力。但是对正常健康人来说它并无用处。
例如，用了生长激素之后可以产生更多的乳酸，这是一种运动之后产物，这可以致痛并使肌肉疲劳。在一项对生长激素是否可以提高运动能力及耐力的研究中，两名自行车运动员在用了激素后因疲劳而中止了练习。
参与这项研究的Andrew Hoffman医生是，内分泌、老年医学和新陈代谢的教授，他说：“主要的一点我们没有发现生长激素可以增强运动员的表现。”
Hoffman 强调另外一些激素可以使运动员的表现出色——特别是雄性激素。
Hoffman 在邮件中强调：“运动员使用的激素比调查人员认为理论上可以用于健康人的量要多，而且，一些运动员常常与其它一些代谢性激素一起使用，如雄性激素。”
他在电话采访中说使用高剂量激素对人产生副作用。“它使你的腿部的积液增多，且使你的关节痛疼。”
他提到：“我们从中得知，有些运动员服用了非常非常大的剂量。”
Hoffman说一些激素的确可以使运动员更加强壮——虽然不是没有风险。他说：“对生长激素的研究没有发现它比其它激素好，如雄性激素以一完全不同的机制起作用。” |
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发表于 2008-4-23 16:55:20