According to the World Anti-Doping Association (WADA), human growth hormone (HGH) is a natural hormone secreted by the anterior pituitary gland and responsible for tissue growth and protein synthesis. Further, WADA explains that HGH assists with cellular metabolism throughout the body. HGH has become a popular performance-enhancing supplement in the athletic world because of its proposed benefits on many bodily functions.
Proposed Benefits of HGH
The book "Physiology of Sport and Exercise" reports that a number of benefits are assumed to be associated with the use of HGH, including increased synthesis of muscle protein, stimulation of bone growth, increased fat metabolism and decreased body fat, increased blood glucose and enhanced injury healing. Whether these proposed benefits are in fact true, and to what degree, is still a matter for debate.
What Research Has Shown
"Physiology of Sport and Exercise" reviewed research conducted on HGH, and concluded that solid evidence supports its effect on increases in body mass, decreased body fat, increased bone density and increased protein synthesis. Some evidence of physiological changes as a result of HGH supplementation clearly exists. "Physiology of Sport and Exercise" reports, however, that this same research has shown no differences in muscle size or strength. Therefore, the actual performance-enhancing effects of HGH remain unclear and are perhaps doubtful.
Adverse Effects on Bone Growth and Development
The National Strength and Conditioning Association describes a number of risks associated with HGH use. Excess secretion of HGH in children can lead to gigantism, an abnormal increase in bone length. Further, acromegaly, a disease in which bones are widened and organs are enlarged, is associated with high levels of HGH secretion. Because of these deleterious effects on bone health, HGH supplementation is not recommended for children whose bones have not fully developed.
Other Health Risks
Aside from the potential risks to bone health, the NSCA also reports a number of other common adverse effects with HGH use. Atrophy, or shrinkage, of the pituitary gland has been known to occur, which can ultimately lead to complete failure of the gland. WADA indicates that carpal tunnel syndrome, edema, and arthritis are also common side effects of HGH use. "Physiology of Sport and Exercise" claims that cardiomyopathy, a weakening of the heart muscle, has been associated with HGH use and is the most common cause of death in HGH users.
Conclusions
There is some evidence that HGH can increase body mass and protein synthesis. However, most research is equivocal, and some has found no performance-enhancing effects associated with HGH use. HGH is associated with several side effects, many of them severe. Therefore, the risks of HGH use appear to outweigh any proposed performance benefits, and most athletic organizations have banned its use.
References
- World Anti-Doping Association: Questions and Answers About Human Growth Hormone
- "The Physiology of Sport and Exercise"; Jack W. Wilmore and David L. Costill (eds.); 2004
- "Essentials of Strength and Conditioning"; Thomas R. Baechle and Roger W. Earle (eds.); 2008
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