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

TLDR

The study examined endocrine adaptations to a 10‑week heavy‑resistance training program in 30‑ and 62‑year‑old men. Participants underwent blood sampling before, immediately after, and at 5, 15, and 30 min post‑exercise, and at rest before and after training, to assay testosterone, cortisol, growth hormone, lactate, ACTH, IGF‑I, and IGF‑binding protein‑3, while a 4‑set 10‑RM squat test evaluated exercise‑induced hormonal responses. Both groups gained squat strength and thigh muscle cross‑sectional area; younger men showed higher baseline and post‑training total and free testosterone and IGF‑I, whereas older men exhibited a significant rise in total testosterone after exercise and a reduction in resting cortisol, indicating an age‑specific hormonal response to early training.

Abstract

To examine the adaptations of the endocrine system to heavy-resistance training in younger vs. older men, two groups of men (30 and 62 yr old) participated in a 10-wk periodized strength-power training program. Blood was obtained before, immediately after, and 5, 15, and 30 min after exercise at rest before and after training and at rest at −3, 0, 6, and 10 wk for analysis of total testosterone, free testosterone, cortisol, growth hormone, lactate, and ACTH analysis. Resting values for insulin-like growth factor (IGF)-I and IGF-binding protein-3 were determined before and after training. A heavy-resistance exercise test was used to evaluate the exercise-induced responses (4 sets of 10-repetition maximum squats with 90 s of rest between sets). 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 testosterone at rest and with exercise, and increases in resting IGF-binding protein-3. With training the older group demonstrated a significant increase in total testosterone in response to exercise stress along with significant decreases in resting cortisol. These data indicate that older men do respond with an enhanced hormonal profile in the early phase of a resistance training program, but the response is different from that of younger men.