Thermoregulation during Sleep in Elderly and Young People

Elderly people are generally less capable of maintaining their core body temperature when exposed to the cold or heat as compared to young individuals (Kenney, 2003). However, between old and young subjects no significant difference was observed with respect to preferred temperature determined by the individual’s self-control (Taylor, 1995) and small difference was found in the thermoneutral temperature (Tsuzuki, 2003), although skin temperature responses differed between old and young subjects (Taylor, 1995; Tsuzuki, 2003). Sleep complaints related to difficulties in initiating and maintaining sleep increase with age because of frequent brief awakenings and short durations of slow-wave sleep (SWS) (Monk et al. 1991; Dorsey et al. 1999). It has reported that the amplitude of the circadian temperature rhythm is significantly lower in elderly subjects than in young men (Vitiello, 1986). The lower circadian amplitude and advanced phase observed in elderly people than in young people in the constant-routine study was probably attributable to both age-related change in circadian pacemakers and reduced homeostatic pressure for sleep (Dijk, 1999). Sleep quality is dependent on both the circadian rhythm and thermoregulation (Someren, 2000). Abundant research has been carried out with regard to sleep in elderly people as compared to that in young people. However, studies on thermoregulation during sleep in elderly people are few (Okamoto-Mizuno, 2004). The aim of the present study is to compare thermoregulation during sleep between healthy old and young individuals.