Modulation of Endocrine Function by Sleep-Wake Homeostasis and Circadian Rhythmicity

Sleep exerts modulatory effects on components of the endocrine system; depending on the endocrine axis hormonal secretion may be stimulated or inhibited during sleep. Reciprocally, several hormones have effects on sleep architecture. The sleep-wake cycle is under dual control of a centrally generated endogenous circadian signal and of a homeostatic mechanism relating sleep duration and intensity to the duration of prior wakefulness. This dual control affects the temporal organization of hormonal release. The physiological response of hormonal secretions to sleep is disturbed during sleep deprivation and when sleep is shallow and/or fragmented. Part of the hormonal and metabolic changes observed in older adults could be secondary to the decreases in sleep duration and quality that characterize aging.