Exercise on its own is a potent growth hormone releaser; however, there are conflicting reports regarding the acute effects of exercise on circulating ghrelin, a hormone that increases appetite, and insulinlike growth factor concentrations. In a new study seven healthy men completed three trials in a random order. In two exercise trials they performed a single 30-second sprint on a cycle ergometer against a resistance equivalent to either 7 percent (FAST) or 9 percent (SLOW) of their body mass. In the other they rested in the laboratory (CON). Blood samples were taken pre-, immediately post-, 10 and 30 minutes after exercise and at equivalent times in the CON trial.
Total ghrelin concentrations declined after the sprint and were significantly lower after 30 minutes of recovery than they were before exercise; also, growth hormone concentrations increased in both exercise trials and were greater in the FAST than the SLOW trial. On the other hand, there were no changes in total insulinlike growth factor I, free IGF-I, total IGF-II and IGF-I bioactivity.
So the best way in this case to increase GH and inhibit ghrelin is with fast sprint exercises.1 Well, what if we had athletes take GH? Forever, it seems, doctors and assorted experts have suggested that GH doesn’t act as an ergogenic aid—at least not as well as the big T. Another recent study proved otherwise.
In a study published in the Annals of Internal Medicine, scientists assessed the effects of growth hormone alone or with testosterone on body composition and measures of performance in a randomized, placebo-controlled, blinded study over eight weeks of treatment followed by a six-week washout period. Ninety-six recreationally trained athletes—63 men and 33 women, average age 28—were studied.
Men were randomly assigned to receive placebo, growth hormone, testosterone or combined treatments. Women were randomly assigned to receive either placebo or growth hormone. Here’s what the researchers found.
Growth hormone significantly reduced bodyfat, increased lean body mass through an increase in extracellular water and increased body cell mass in men when given with testosterone. Growth hormone significantly increased sprint capacity in men and women on its own and when given with testosterone to men; however, other performance measures did not significantly change. The increase in sprint capacity was not maintained six weeks after the drug was discontinued.
So there you have it: The combination that is so prevalent among elite athletes—GH + T—does indeed have an ergogenic effect, and so does GH by itself in the fair sex.2 Now, what happens when you really jack the doses sky high?
One more piece of news: You’ve heard of the beneficial effects of selective androgen receptor modulators, or SARMs, relative to osteoporosis and muscle wasting. A recent study found that the androgen receptor is important in regulating female libido and that SARMs could be a superior alternative to steroidal testosterone preparations in the treatment of hypoactive sexual desire disorder.3 Meaning, not only will SARMs give you muscle, but it can also be used to make your girlfriend or wife hornier. Isn’t science great?
Editor’s note: Jose Antonio, Ph.D., is the CEO of the International Society of Sports Nutrition (www.theissn.org); also check out his site www.TheWeekendWorkout.com.
1 K.A. Stokes, et al. (2010). Brief, high intensity exercise alters serum ghrelin and growth hormone concentrations but not IGF-1, IGF-2 or IGF-1 bioactivity. Growth Horm IGF Res. May 14.
2 U. Meinhardt, et al. (2010). The effects of growth hormone on body composition and physical performance in recreational athletes: a radomized trial. Ann Intern Med.152:568-77.
3 A.M. Jones, et al. (2009). Influence of dietary creatine supplementation on muscle phosphocreatine kinetics during knee extensor exercise in humans. Am J Physiol Regul Integr Comp Physiol. 296:R1078.