Urhausen, A., Gabriel, H. W., & Kindermann, W. (1998). Impaired pituitary hormonal response to exhaustive exercise in overtrained endurance athletes. Medicine and Science in Sports and Exercise, 30, 407-414.

The hormonal responses of overtrained male athletes (N = 17) at rest and during exercise consisting of a short-term exhaustive endurance cycle-ergometer test at 10% above anaerobic threshold were evaluated over 19 months in overtrained and normal training states.

Overtrained states were promoted by increasing the frequency of high-intensity training or competitions without an increase in training volume. Rather than producing states of chronic overtraining, overtraining in this investigation was regarded as being "short-term."

When overtrained, the average time to exhaustion was decreased by 27%. At rest and during exercise there was no difference between the two states in the concentrations in plasma and the nocturnal excretion in urine of free epinephrine and norepinephrine. At physical rest the concentrations of free testosterone, cortisol, luteinizing hormone, follicle-stimulating hormone, adrenocorticotropic hormone, growth hormone, and insulin were similar in both conditions. After exercise significant decreases in adrenocorticotropic hormone, growth hormone, and insulin were recorded.

These results confirm the hypothesis of a hypothalamic-pituitary dysfunction during exercise in short-term overtrained (over-reached) athletes.

Implication. Further research to evaluate hypothalamic-pituitary dysfunction during exercise in short-term overtrained athletes is warranted.

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