Exercise and growth hormone in the aging individual, with special reference to the exercise-induced growth hormone response
International Federation of Sports Medicine
Faculty of Computing, Health and Science
School of Exercise, Biomedical and Health Science, Centre for Exercise and Sports Science Research
This review examines the mechanisms of growth hormone (GH) action, its effects on physical work capacity, and the effects of exercise training on the age-related decline in GH secretion. Data sources: Scientific research articles and literature reviews published in refereed journals prior to 01/04/2004 were scrutinised. Literature searches were conducted on electronic databases; articles not found in our search but cited by others were also obtained and textbooks published after 1985 were consulted. Study section: 443 sources citing GH research and related topics were consulted. 114 sources were considered to have information specifically relevant to the topic. Data extraction: By systematic collection of relevant information and by contrasting the results of research articles it was found that there is an age-related decrease in GH secretion that is not completely reversible with clinical or exercise interventions. This is associated with muscle atrophy, lower physical work capacity and increased adiposity in older individuals. Acute bouts of intense exercise result in significant increases in circulating GH in older individuals, and this release is greater in those who have prolonged training experience. Exogenous recombinant GH treatments are at best only equally effective, possibly because GH exerts greater influence when levels of other hormones, and their binding proteins, are optimised. Conclusions: High-intensity exercise largely offsets the age-related GH decrease by significantly elevating GH secretion. There is little evidence that exogenous GH treatment has a significant effect on physical work capacity. Hence appropriate exercise, including regular high intensity activity, could help minimise any age-associated decline.