Effects of passive body heating on body temperature and sleep regulation in the elderly: a systematic review

Insomnia in the elderly is associated with circadian body temperature changes. Manipulating body temperature prior to sleep onset may improve sleep quality in the elderly. This systematic review analyzed the effect of passive body heating on body temperature and sleep quality. Three studies related to passive body heating for the elderly identified from a computerized database search were evaluated. All of them used crossover designs to examine effects of passive body heating on sleep quality. Passive body heating such as a warm bath immersed to mid-thorax with 40–41°C water for 30 min in the evening could increase rectal body temperature, delay occurrence of body temperature nadir and increase slow wave sleep (deep sleep) in healthy female elderly with insomnia. The elderly also perceived “good sleep” or “quickness of falling asleep” after the bathing condition. Evening warm bath facilitates nighttime sleep for the healthy elderly with insomnia.