Ergogenic aids such as human growth hormone, or HGH, have become popular despite safety concerns. These substances improve athletic performance by increasing strength and facilitating recovery. Patients with reduced levels of growth hormone experience subtle improvements by taking HGH, but the significance of such changes remains unclear. People using growth hormone also report side effects, which can put them at risk for disease and injury. Consult with a doctor before self-medicating with HGH supplements.
Aerobic Capacity
People with HGH deficiencies often have problems with cardiovascular health and body composition. Growth hormone intake can reverse these changes, and it may affect measures of athletic performance as well. A 1998 paper in "Growth Hormone & IGF Research" looked at the hormone's impact on adults who had low levels of HGH as children. Participants received daily treatment for six months. The hormone increased aerobic capacity relative to a placebo. That is, it enhanced the subjects' ability to use oxygen during incremental exercise. Such changes would benefit athletes during a competition. No adverse events occurred throughout treatment, but the long-term effects remain unknown.
Respiratory Function
Long-term intake of anabolic steroids causes unwanted reactions. Athletes thus take "drug holidays" to reduce these side effects. During such periods, they use other performance-enhancing drugs to maintain their gains. A 2007 article in "Growth Hormone & IGF Research" tested the effectiveness of this strategy. Previous users of steroids received HGH for six days. They were then given respiratory tests with the results compared to those of a control group. Growth hormone enhanced forced expiratory volume, maximum inspiratory pressure and maximum expiratory pressure. These data show that HGH improved respiratory function, a measure of fitness. It remains unclear whether tests in subjects not regularly using steroids would reveal similar results.
Muscle Strength
Athletes often take growth hormone to enhance their physical strength, yet scientific data do not support this use. Tests in people with low HGH, however, do reveal a strength-enhancing effect. A 2009 investigation presented in the "Journal of Clinical Endocrinology & Metabolism" evaluated the impact of growth hormone in HGH-deficient adults. Patients received growth hormone for 10 years. Relative to baseline, treatment enhanced hand and leg strength. Effects were largest during the first five years, yet remained stable throughout the study. The subjects tolerated the HGH treatment well, but they often reported mild reactions, such as bloating. Identical tests in healthy adults appear unlikely to produce comparable data.
Exercise Efficiency
Growth hormone facilitates the conversion of food into fatty acids. This positive effect of HGH may allow professional and recreational athletes to perform more efficiently. A 2004 report in the "Journal of Clinical Endocrinology & Metabolism" assessed growth hormone's effect on stationary cycle performance. The authors gave healthy subjects HGH or placebo during a single testing session. Volunteers given the growth hormone required less effort to complete the tests than those given an inert treatment. They used less oxygen to do the same amount of work and reported no side effects. Yet, scientists must collect more data before HGH can be recommended as an ergogenic agent.
References
- "Growth Hormone & IGF Research"; Exercise Capacity and Hormonal Response in Adults With Childhood Onset Growth Hormone Deficiency During Long-Term Somatropin Treatment; Lars Gullestad, et al.; October 1998
- "Growth Hormone & IGF Research"; Short-Term Recombinant Human Growth Hormone Administration Improves Respiratory Function in Abstinent Anabolic-Androgenic Steroid Users; Michael R. Graham, et al.; August 2007
- "Journal of Clinical Endocrinology & Metabolism"; Ten Years of Growth Hormone (GH) Replacement Normalizes Muscle Strength in GH-Deficient Adults; Galina Gotherstrom, et al.; March 2009
- "Journal of Clinical Endocrinology & Metabolism"; Effects of Time Following Acute Growth Hormone Administration on Metabolic and Power Output Measures During Acute Exercise; Brian A. Irving, et al.; September 2004
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