title: Effects of sleep pressure on endogenous cardiac autonomic activity and body temperature.
abstract: This study investigated the effects of variations in sleep pressure on cardiac autonomic activity and body temperature. In a counterbalanced design, 12 healthy, young subjects (6 men and 6 women) remained recumbent during 30 h of wakefulness (high sleep pressure) and 6 h of wakefulness (low sleep pressure). Both periods of wakefulness were immediately followed by a sleep opportunity, and the first 2 h of sleep were analyzed. During extended hours of wakefulness, a reduction in heart rate was mediated by a decline in cardiac sympathetic activity (measured via preejection period) and the maintenance of cardiac parasympathetic activity (measured via respiratory sinus arrhythmia). In subsequent high-pressure sleep, parasympathetic activity was amplified and sympathetic activity was negatively associated with electroencephalographic slow-wave activity. Sleep deprivation had no impact on foot temperature, but it did alter the pattern of change in core body temperature. A downregulation of cardiac autonomic activity during both extended hours of wakefulness and subsequent sleep may respectively provide "protection" and "recovery" from the temporal extension of cardiac demand.
authors.affiliation: Centre for Sleep Research, University of South Australia, Woodville, South Australia 5011, Australia. alex.holmes@unisa.edu.au
authors.forename: Alexandra L
authors.initials: AL
authors.lastname: Holmes
authors.forename: Helen J
authors.initials: HJ
authors.lastname: Burgess
authors.forename: Drew
authors.initials: D
authors.lastname: Dawson
mesh_terms: D000328:Adult; D001341:Autonomic Nervous System / Q000502:physiology*; D001831:Body Temperature / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D006329:Heart Conduction System / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D011312:Pressure; D012890:Sleep / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology