Aging does not affect the sleep endocrine response to total sleep deprivation in humans

Aging is associated with decreased sleep continuity, slow wave sleep (SWS), growth hormone (GH) release and an increased hypothalamo-pituitary-adrenoc ortical (HPA) system activity. Total sleep deprivation (TSD) is a strong st imulus for sleep. To determine if aging affects the response to TSD, for th e first time the combined effects of TSD on conventional and spectral sleep electroencephalographic (EEG) parameters and GH, cortisol and prolactin se cretion were compared in elderly (60-80 years; n = 7) vs. younger subjects (20-30 years; n = 7). MANOVA revealed a reduction of SWS in the elderly. TS D led to an increase in SWS, a decrease in sleep onset latency, rapid eye m ovement (REM) density and by trend REM-latency without a global group diffe rence. GH was reduced, whereas prolactin was enhanced in the elderly. After TSD GH was unchanged and prolactin secretion was enhanced without group di fference. Thus, the plasticity of the sleep-endocrine system in response to TSD is sustained during aging. The possible involvement of the GABAergic s ystem, that seems not to be severely impaired with age, is proposed. (C) 20 00 Elsevier Science Inc. All rights reserved.