Core body temperature is elevated during constant wakefulness in elderly poor sleepers

Study Objectives: The aim of this study was to test for heightened physiolo gical activity in elderly poor sleeepers compared to good sleepers under ad lib sleep and constant wakeful conditions. Design and Setting: Subjects participated in a five-day protocol consisting of four nights of polysomnographic (PSG) and rectal temperature monitoring followed by 26hours of continuous rectal temperature monitoring under cont rolled constant wakefulness. Participants: Participants were 16 self-reported sleep maintenance insomnia cs and 16 self-reported good sleeping controls over 55 years of age. Interventions: NA Measurement and Results: Subjects were grouped according to (1) subjective sleep status and (2) into quartiles according to amount of PSG determined w ake after sleep onset (WASO). Significant group differences in temperature were observed when subjects were classified according to PSG but not subjec tive criteria. In the former case, subjects with the lowest (bottom quartil e) compared to the highest (top quartile) amount of PSG determined WASO sho wed lower sleep and nighttime constant wakeful core body temperatures. Conclusions: In the elderly, elevated core body temperature is associated w ith increased nocturnal wakefulness suggesting that physiological activatio n may underlie sleep maintenance insomnia. This was clearly significant whe n subjects were compared using objective criteria and temperature was colle cted under constant wakeful conditions.