Several studies have reported that suitable manipulation of human skin or body temperature can lead to improved sleep. To clarify the effect of skin warming on human sleep, 38 female subjects, who occasionally had difficulty with falling asleep, were studied. The participants underwent two experimental sessions, which were carried out in two consecutive follicular phases and randomly crossed over. The participants wore hot or sham eye masks in one 14-day session. The first half of each 14-day session was designated the baseline period (BL) without any interventions and the later half was designated the intervention period (INT), in which they wore either the hot or sham eye mask for 10 minutes at bedtime. All the participants were instructed to keep a sleep diary every morning for the BL and INT. The results showed that the hot eye mask was significantly preferred over the sham one with respect to comfort and that feelings of restfulness and being refreshed upon wakening in the morning were significantly better with the hot eye mask than with the sham. These results suggest that bedtime periocular warming has favorable effects on subjective well-being on awakening, possibly due to the sense of comfort experienced at bedtime.
Sakamoto, I., Igaki, M., Ichiba, T., Suzuki, M., Kuriyama, K., & Uchiyama, M. (2017). Effects of Bedtime Periocular Warming on Sleep Status in Adult Female Subjects: A Pilot Study. Evidence-Based Complementary and Alternative Medicine, 2017. https://doi.org/10.1155/2017/6419439