TESTOSTERONE AND CORTISOL IN RELATIONSHIP TO DIETARY NUTRIENTS AND RESISTANCE EXERCISE

Manipulation of resistance exercise variables (i.e., intensity, volume , and rest periods) affects the endocrine response to exercise; howeve r, the influence of dietary nutrients on basal and exercise-induced co ncentrations of hormones is less understood. The present study examine d the relationship between dietary nutrients and resting and exercise- induced blood concentrations of testosterone (T) and cortisol (C). Twe lve men performed a bench press exercise protocol (5 sets to failure u sing a 10-repetitions maximum load) and a jump squat protocol (5 sets of 10 repetitions using 30% of each subject's 1-repetition maximum squ at) with 2 min of rest between all sets. A blood sample was obtained a t preexercise and 5 min postexercise for determination of serum T and C. Subjects also completed detailed dietary food records for a total o f 17 days. There was a significant (P less than or equal to 0.05) incr ease in postexercise T compared with preexercise values for both the b ench press (7.4%) and jump squat (15.1%) protocols; however, C was not significantly different from preexercise concentrations. Significant correlations were observed between preexercise T and percent energy pr otein (r = -0.71), percent energy fat (r = 0.72), saturated fatty acid s (g . 1,000 kcal(-1) . day(-1); r = 0.77), monounsaturated fatty acid s (g . 1,000 kcal(-1) . day(-1); r = 0.79), the polyunsaturated fat-to -saturated fat ratio (r = -0.63), and the protein-to-carbohydrate rati o (r = -0.59). There were no significant correlations observed between any nutritional variables and preexercise C or the absolute increase in T and C after exercise. These data confirm that high-intensity resi stance exercise results in elevated postexercise T concentrations. A m ore impressive finding was that dietary nutrients may be capable of mo dulating resting concentrations of T.