TEMPORAL RELATIONSHIPS BETWEEN PULSATILE CORTISOL SECRETION AND ELECTROENCEPHALOGRAPHIC ACTIVITY DURING SLEEP IN MAN

A temporal link between slow wave sleep and low or decreasing cortisol release has been previously demonstrated. This relationship was re-ev aluated in 15 healthy male subjects using spectral analysis of their s leep electroencephalogram (EEG). EEG activity in the delta, theta, alp ha and beta bands was cross-correlated with cortisol secretory rates a t 10-min intervals. For the period of pulsatile cortisol secretion, an inverse relationship was found with the delta band with an average cr oss-correlation coefficient of -0.505 (P < 0.0001). Variations in cort isol secretory rates coincided with or anticipated opposite variations in delta wave activity by 10 or 20 min. A significant positive correl ation was found with theta activity, but alpha and beta bands did not elicit any systematic association with cortisol profiles. These result s demonstrate a temporal association between cortisol secretory pulses and delta wave activity in man, suggesting the existence of a central control common to both variables. (C) 1997 Elsevier Science Ireland L td.