The effect on sleep of fabric for sleeping apparel and bedding

Abstract

Good sleep promotes physical and psychological health. Clothing and bedding provide thermal insulation and can impact on thermal comfort and sleep. However, heat or cold exposure could disrupt sleep and alter sleep stages. Textile fabrics with different fibre characteristics have influences on thermal and moisture resistance. Therefore, this thesis explored the influence of the fabrics of cotton, polyester and wool on sleep. For study 1, the participants slept in cotton, polyester and wool singlets and shorts at 29°C. Sleep onset latency (SOL), arousal index and wake after sleep onset were reduced in wool compared to the other fabrics. Study 2 explored the effects of sleeping apparel (cotton vs. wool), bedding (polyester vs. wool) and ambient temperature (Ta) (17°C vs. 22°C) on sleep. Wool apparel and lower Ta (17C) were more conducive to sleep. At 17C, sleeping in wool promoted an early sleep onset, increased stage 3 sleep but decreased stage 2 sleep compared to cotton apparel, whereas at 22C sleeping in cotton promoted increase stage 3 sleep than in wool. However, no effects were observed for bedding types. The skin and core body temperature data supported findings in SOL at 17C, but not findings in stage 3 sleep at 22C. Concordance in sleep measures was assessed between polysomnography (the standard measurement), Actiwatch 2 and SenseWear armband (portable sleep measurements). The data showed similar validity for sleep detection by both devices, except that the SenseWear armband was dependent on Ta especially at 29°C. Overall, the thesis findings showed that sleeping in wool apparel promoted sleep at 29C when in singlets and shorts, and at 17C when in long sleeves and pants. Sleeping in cotton apparel favoured sleep at 22C. The findings were discussed with respect to the properties of fabric fibres in terms of air trapping and hygroscopicity.