A single-group crossover design was used to examine the effects of a warm footbath on body temperatures, distal-proximal skin temperature gradient (DPG), and sleep outcomes in 15 Taiwanese elders with self-reported sleep disturbance. Body temperatures and polysomnography were recorded for 3 consecutive nights. Participants were assigned randomly to receive a 41°C footbath for 40 minutes before sleep onset on night 2 or night 3. Mean DPG before lights off was significantly elevated on the bathing night. There were no significant differences in sleep outcomes between the two nights. However, when the first two non-rapid eye movement (NREM) sleep periods were examined, the amount of wakefulness was decreased in the second NREM period on the bathing night.
Keywords
sleep/rest; agingInsomnia is a common complaint in older adults. They have trouble falling asleep, as well as frequent or prolonged nocturnal or early morning awakenings with an inability to return to sleep (Ancoli-Israel, 1997;Ancoli-Israel & Roth, 1999;Floyd, Medler, Ager, & Janisse, 2000). The overall prevalence of insomnia in the elderly ranges from 14.0% -42.2% based on epidemiological surveys (Chiu et al., 1999;Kim, Uchiyama, Okawa, Liu, & Ogihara, 2000;Ohayon, 1996). As many as 25% of healthy elderly men and women may have chronic insomnia (Ohayon & Smirne, 2002). Global sleep dissatisfaction, defined as overall dissatisfaction with sleep, ranges from 7.7 -20.8% in the elderly, which is higher than in the general population (7.0-10.1%; Pallesen et al., 2001).Sleep is periodic resting behavior characterized by "few body movements, a recumbent posture, and complex brain electroencephalographic activity" (Carskadon & Dement, 2000, p.15). Human sleep architecture is defined by polysomnography (PSG) and divided into stages: four of non-rapid eye movement (NREM) sleep (stage 1 to 4), and one stage of rapid-eye movement (REM) sleep (Rechtschaffen & Kales 1968 Age has large effects on sleep architecture. Compared to young adults, PSG-derived sleep architecture in older adults shows increased amounts of nocturnal wakefulness, increased NREM stage 1 sleep with reduced amounts or complete absence of NREM stages 3 and 4 sleep (Floyd et al., 2000;Van Someren, 2000a). In some studies, the percentage of REM sleep was reduced slightly in older adults (Van Cauter, Leproult, & Plat, 2000), whereas findings from other studies showed that older adults experienced typical amounts of REM sleep (Campbell & Murphy, 1998). Long sleep latencies (e.g. > 30 minutes), reduced sleep efficiency (e.g. < 85%), and a sleep duration of ≤ 6 hours were common in older adults. These characteristics are consistent with the criteria of insomnia, although not all older adults complained of poor sleep (Vitiello, Larsen, & Moe, 2004).In addition to changes in sleep architecture, there are changes in the circadian rhythm of body temperature in older adults compared to young adults. A circadian rhythm is the variation in body functions and behaviors that occur in a regular pattern ar...