RELATIONSHIP BETWEEN INCREASES IN PLASMA CORTISOL CONCENTRATION AND RATE OF CORTISOL SECRETION DURING EXERCISE IN MAN (original) (raw)

MRC Environmental Physiology Unit, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT

(Received 10 September 1976)

Exercise for 1 h, at work loads exceeding about 60% of a subject's maximum aerobic power (_V̄O_2, max), generally leads to a rise in plasma cortisol concentration (Davies & Few, 1973). The observed rise in plasma cortisol level is the net effect of increases in both the rate of secretion, and the rate of removal from the plasma, of cortisol (Few, 1974). Occasionally exercise at work loads exceeding 70% _V̄O_2, max fail to elicit a significant rise in plasma cortisol level. Such a result could be due either to a failure to increase the rate of cortisol secretion or to an unusually rapid rate of cortisol removal.

In an attempt to resolve this ambiguity we have analysed data from ten experiments on normal men who exercised for 1 h at