Resistance exercise-induced hormonal responses in men, women, and pubescent boys

This study was designed to investigate the acute plasma catecholamine (CA) response to resistance exercise and its association with serum testosterone (TES), cortisol (COR), and growth hormone (GH) concentration changes. Six men, six women, and six adolescent boys (14 +/- 0 yr) performed five sets of 10 knee extensions with 40% of one-repetition maximum followed by two sets performed to exhaustion. Arterialized venous blood was sampled before, during, and after the exercise for the hormone analysis. External work performed (Wext), average EMG normalized for maximal EMG, exercise-induced maximal voluntary contraction decline, and plasma volume change (deltaPV) were also determined. No differences between groups were observed in Wext relative to lean body mass, average EMG, or in exercise-induced fatigue. Plasma norepinephrine (NE) concentrations were similar in the three groups. However, peak plasma epinephrine (E) increase from preexercise was about twice as high in boys (5.0 +/- 2.6 nmol.L-1 as in men (2.5 +/- 0.8 nmol.L-1] and in women (2.1 +/- 0.6 nmol.L-1) (P < 0.05). The deltaPV could explain a significant increase in serum TES concentration in men, and increases in GH concentrations in every group, but not that of COR observed only in boys. No correlation between the CA concentration changes and those of the other hormones were observed even if the groups were combined. No associations between the CA and the other hormone responses were observed. However, the results may suggest a trend for higher stress response to this particular exercise in the boys than in adults.