Association of bedroom environment with the sleep quality of elderly subjects in summer: A field measurement in Shanghai, China. (15th January 2022)

• Record Type: Journal Article
• Authors: Yan, Yan; Lan, Li; Zhang, Haodong; Sun, Yuxiang; Fan, Xiaojun; Wyon, David Peter; Wargocki, Pawel
• Is Part Of: Building and environment. Volume 208(2022)
• Publication Date: 2022-01-15
• Subjects: Elderly occupants -- Bedroom -- Thermal environment -- Ventilation -- Sleep quality; Buildings -- Environmental engineering -- Periodicals; Building -- Research -- Periodicals; Constructions -- Technique de l'environnement -- Périodiques; Electronic journals; 696
• DOI: 10.1016/j.buildenv.2021.108572
• Languages: English
• ISSNs: 0360-1323

Abstract

Abstract: Sleep is essential for the health of elderly people, but few studies have made connection between their sleep quality and their bedroom environment. This study performed field measurements in Shanghai, China, to investigate the bedroom thermal environment and ventilation and their associations with the sleep quality of elderly subjects in summer. Forty-five elderly subjects participated in this study for six consecutive days. Their bedroom air temperature, relative humidity and CO2 concentration were measured continuously and their sleep quality was objectively measured using a wrist-worn sleep tracker. Wrist skin temperature was measured continuously at night. Each morning after waking up the subjects assessed their sleep quality, recalled their thermal sensation, and recorded their bed covering, sleepwear and cooling/ventilation arrangements during that night. The results show that higher air temperature and CO2 concentration were both negatively correlated with objective sleep quality. Air temperature was the key factor influencing objective sleep quality. When air temperature increased by 1 °C, sleep efficiency (SE) decreased by 0.7%, duration of Rapid Eye Movement (REM) sleep decreased by 2.1min, and time awake increased by 2.3min. The sleep quality of elderly subjects was more negatively affected by heat exposure than has been previously reported for younger subjects. As CO2 concentration increased by 100 ppm, the Total Sleep Time (TST) decreased by 11min. The combined effects of air temperature, relative humidity and CO2 concentration were analyzed: TST and duration of REM sleep were reduced at higher air temperature, relative humidity and CO2 concentration. Graphical abstract: Image 1 Highlights: The elderly subjects preferred to open doors/windows at night in summer. Their sleep quality decreased with increased air temperature and CO2 concentration. Thermal environment and CO2 concentration interactively affected sleep quality. Wrist skin temperature could be a good marker of thermal sensation and sleep quality.