Serum FSH, LH, and testosterone in humans after physical exercise.

The serum levels of FSH, LH, and testosterone were determined by radioimmunoassay in 63 men before, during, and after maximal and submaximal physical short- and long-term exercise (800-n running, climbing, 36-k cross-country skiing). In the 800-meter run, significant elevations of FSH, LH, and testosterone were observed, while in all other field and laboratory test (climbing, 36-km cross-country skiing, maximal stepwise bicycle and treadmill ergometry, 90-min submaximal bicycle ergometry) the hormone levels remained unchanged or were decreased. In contrast to FSH and LH, which did not show any clear modification with duration or intensity of exercise or with the state of training, changes of testosterone in the endurance field test (36-km cross-country skiing) seemed to be training dependent. In highly endurance-trained subjects, there was an increase and in less well-trained subjects a decrease of testosterone for equal distances and intensities of exercise.