How do sleepwear and bedding fibre types affect sleep quality: A systematic review

“This systematic review was conducted in accordance with the recommendations outlined in the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement (Page et al., 2021).”

“Since humans are sensitive to temperature differences (Fanger, 1970) which influence thermal comfort and sleep propensity and quality (Gagge et al., 1967; Lan et al., 2017), sleep outcomes from different studies are not directly comparable.”

“In adherence to the CONSORT statement (Dwan et al., 2019), cross-over studies of randomised design are an extension of RCT, therefore the risk-of-bias of three studies (Araujo et al., 2013; Chow et al., 2019; Shin et al., 2016) was evaluated using the JBI-RCT tool.”

“Thermal comfort is a condition of mind that expresses satisfaction with the thermal environment (Auliciems & Szokolay, 1997) with a need to maintain a stable core body temperature (Nicol et al., 2012), in this way, it varies from person to person (Djongyang et al., 2010).”

“During the sleep period, the skin temperature remains relatively stable, with a slight increase during rapid eye movement (REM) sleep (Okamoto-Mizuno & Mizuno, 2012).”

“Skin temperature plays an essential role in thermoregulation, as receptors for warmth and cold detection found in the skin help adjust peripheral blood flow and control heat loss (Krauchi et al., 2000; Xu & Lian, 2023).”

“Among the environmental factors, the thermal environment is very important for sleep maintenance (Lan et al., 2014; Lan et al., 2017; Troynikov et al., 2018).”

“Sleep quality can be affected by many factors such as health behaviours, physical health, psychological health (Xu et al., 2014), as well as environmental factors such as light, noise, temperature, air pollution, social neighbourhood safety, etc. (Johnson et al., 2018; Troynikov et al., 2018).”

“Among the environmental factors, the thermal environment is very important for sleep maintenance (Lan et al., 2014; Lan et al., 2017; Troynikov et al., 2018).”

“Sleep quality can be affected by many factors such as health behaviours, physical health, psychological health (Xu et al., 2014), as well as environmental factors such as light, noise, temperature, air pollution, social neighbourhood safety, etc. (Johnson et al., 2018; Troynikov et al., 2018).”

“…of wool sleepwear (9.9 KJ (cid:4) m (cid:2) 2 ) compared with polyester (0.6 KJ (cid:4) m (cid:2) 2 ) or cotton (6.9 KJ (cid:4) m (cid:2) 2 ) (Pan et al., 2012) potentially contributed to a faster sleep onset, which was associated with a fall in core body temperature and a rise in distal…”

“This suggests that these individuals may prefer sleeping at a higher ambient temperature for more favourable thermal comfort (Giamalaki & Kolokotsa, 2019; Wong et al., 2009) which wool sleepwear can provide due to its superior insulation and moisture transport properties (Ukponmwan, 1993).”

“There is a strong tendency for sleep termination when sleep occurs at the temperature peak (acrophase) (Monk, 1987).”

“A lower SFI reflected fewer stage shifts and less thermal stress under hot humid conditions (Hosseini Ravandi & Valizadeh, 2011), which may be linked to the beneficial moisture transfer and the wicking properties of wool.”

“This suggests that these individuals may prefer sleeping at a higher ambient temperature for more favourable thermal comfort (Giamalaki & Kolokotsa, 2019; Wong et al., 2009) which wool sleepwear can provide due to its superior insulation and moisture transport properties (Ukponmwan, 1993).”

“…seven were sleepwear (Araujo et al., 2013; Chow et al., 2019; Lee et al., 2004; Nejedlá & Mina ˇ rík, 2016; Okamoto-Mizuno et al., 2015; Shin et al., 2016; Utkun et al., 2015), two included quilt filler (He et al., 2019; Shin et al., 2016), and one included bedsheets (Okamoto-Mizuno et al., 2013).”

“This suggests that these individuals may prefer sleeping at a higher ambient temperature for more favourable thermal comfort (Giamalaki & Kolokotsa, 2019; Wong et al., 2009) which wool sleepwear can provide due to its superior insulation and moisture transport properties (Ukponmwan, 1993).”

“…be high to allow sweat to evaporate from the skin and to keep the skin dry (Kothari, 2006), for example, wool has a higher water vapour permeability than cotton and polyester, which allows efficient sweat evaporation, keeping the skin dry and enhancing thermal comfort (Bhatia & Malhotra, 2016).”

“Previous studies have shown that an excessively high, low, or fluctuating air temperature can compromise sleep quality (Fletcher et al., 1999; Lan et al., 2014; Yao et al., 2007; Yao et al., 2011).”

“Achieving thermal comfort plays a vital role in maintaining good sleep quality (Lan et al., 2017; Macpherson, 1973; Xu & Lian, 2023).”

“Sleep quality can be affected by many factors such as health behaviours, physical health, psychological health (Xu et al., 2014), as well as environmental factors such as light, noise, temperature, air pollution, social neighbourhood safety, etc. (Johnson et al., 2018; Troynikov et al., 2018).”

“Skin temperature plays an essential role in thermoregulation, as receptors for warmth and cold detection found in the skin help adjust peripheral blood flow and control heat loss (Krauchi et al., 2000; Xu & Lian, 2023).”

“…seven were sleepwear (Araujo et al., 2013; Chow et al., 2019; Lee et al., 2004; Nejedlá & Mina ˇ rík, 2016; Okamoto-Mizuno et al., 2015; Shin et al., 2016; Utkun et al., 2015), two included quilt filler (He et al., 2019; Shin et al., 2016), and one included bedsheets (Okamoto-Mizuno et al., 2013).”

“…studies did not report the temperature conditions (Araujo et al., 2013; Lee et al., 2004; Nejedlá & Mina ˇ rík, 2016) or fibre material properties (Araujo et al., 2013; Neje-dlá & Mina ˇ rík, 2016; Zaki et al., 2021), making it difficult to draw definitive conclusions about the effects of…”

“A study conducted among older adults (Chow et al., 2019) also showed a similar result that sleepwear significantly reduced the SOL compared with cotton ( p = 0.044) with no effect.”

“…2015) or natural and synthetic materials (Okamoto-Mizuno et al., 2015), (2) the target populations and study environment differed in that Lee et al. (Lee et al., 2004) studied healthy girls aged 12 ± 2 years in a sleep laboratory, while two studies conducted home studies in young children (7…”

“Previous studies have shown that an excessively high, low, or fluctuating air temperature can compromise sleep quality (Fletcher et al., 1999; Lan et al., 2014; Yao et al., 2007; Yao et al., 2011).”

“Previous studies have shown that an excessively high, low, or fluctuating air temperature can compromise sleep quality (Fletcher et al., 1999; Lan et al., 2014; Yao et al., 2007; Yao et al., 2011).”

“For example, a systematic review by Xinzhu Li et al. reported that optimal bedding varies depending on the population and environmental conditions 37 .”

“A recent systematic review further concluded that sleepwear and bedding fiber types may affect sleep quality, although the available evidence remains heterogeneous [31].”

“…factors including local climate acclimatization, 38 personal temperature preferences, 39 temperature device measurement accuracy, ambient temperature interaction with sleepwear, bedding and air circulation 40 may influence thermal comfort and sleep differently than our temperature findings suggest.”

“Characteristics of the participants were first obtained from a questionnaire, including age, sex, residential area, and the environment of sleep such as whether they sleep on the bed and have a pillow, bolster, blanket [39], or a partner in one room [31].”

“…may still be useful, including shading rooms during the day [90], using night-time ventilation when outdoor conditions are cooler than indoors [91], reducing bedding insulation [92], using breathable and lightweight sleepwear [93], and relocating sleep to the coolest room of the house [94 – 96].”