Endocrine Abstracts

Introduction: Physical exercise exerts several effects on endocrinological homeostasis and, in particular, sprint exercise elicits the largest testosterone response per unit of work, while in response to prolonged endurance exercise testosterone levels will typically decline. In contrast to a large amount of paper about the modification of testosterone during physical exercise few study evaluated how DHT was influenced by a single bout of aerobic exercise.

Design: Twelve healthy trained male volunteers involved in non-competitive team sports were included and performed maximal exercise test (MAX) and sub-maximal exercise test (sMAX) at the individual anaerobic threshold (IAT). One week before starting the experimental phase, each volunteer underwent a MAX started with a 1-min warm-up without any added load then the workload was increased 30 w every 3 min until exhaustion. This test was used also to evaluate the IAT and the maximal oxygen uptake (O_2max). The sMAX consisted of pedaling 30 min at IAT workload. Blood collections were performed immediately before (0-pre) starting each exercise test, immediately after stopping exercise (0-post), and at +15, +30, and +60 min during recovery. Following each blood collection the serum was separated and stored at −30°C until it was assayed for total testosterone (TT) and DHT.

Results: TT increased significantly after MAX and sMAX from 0-post and remain elevated till +60. DHT concentration increase significantly after MAX (from 0-post) and remain elevated during all recovery (to +60).

Conclusion: Due to the lack of parallelism increase between TT and DHT in both type of exercise, we could exclude that the increase of DHT is related to a conversion of Testosterone by 5 alpha reductase after MAX and we suggest that steroids increases could represent a specific adaptive response to physiological needs related to the intensity of aerobic exercise.