Effects of heavy-resistance training on hormonal response patterns in younger vs. older men

To examine the adaptations of the endocrine system to heavy-resistance trai ning in younger vs. older men, two groups of men (30 and 62 yr old) partici pated in a 10-wk. periodized strength-power training program. Blood was obt ained before, immediately after, and 5, 15, and 30 min after exercise at re st before and after training and at rest at -3, 0, 6, and 10 wk for analysi s of total testosterone, free testosterone, cortisol, growth hormone, lacta te, and ACTH analysis. Resting values for insulin-like growth factor (IGF)- I and IGF-binding protein-3 were determined before and after training. A he avy-resistance exercise test was used to evaluate the exercise-induced resp onses (4 sets of 10-repetition maximum squats with 90 s of rest between set s). Squat strength and thigh muscle cross-sectional area increased for both groups. The younger group demonstrated higher total and free testosterone and IGF-I than the older men, training-induced increases in free testostero ne at rest and with exercise, and increases in resting IGF-binding protein- 3. With training the older group demonstrated a significant increase in tot al testosterone in response to exercise stress along with significant decre ases in resting cortisol. These data indicate that alder men do respond wit h an enhanced hormonal profile in the early phase of a resistance training program, but the response is different from that of younger men.