The effects of fabric for sleepwear and bedding on sleep at ambient temperatures of 17°C and 22°C

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

Sleepwear and bedding materials can affect sleep quality by influencing the skin and body temperature and thermal comfort. This review systematically evaluates the impact of sleepwear or bedding of different fibre types on sleep quality. A systematic search was conducted in six data bases plus Google Scholar and manual searches. Original articles that compared human sleep quality between at least two fibre types of bedding or sleepwear were included, resulting in nine eligible articles included in the review. The fibre types included cotton, polyester, wool, and blended materials for sleepwear; cotton, duck down, goose down, polyester and wool for duvet; and linen and a combination of cotton and polyester for bedding. The interplay between fibre materials and sleep quality is complex. Blended sleepwear demonstrated potential benefits for specific populations. Wool sleepwear showed benefits for sleep onset in adults (cool conditions) and in older adults (warm conditions). Linen bedsheets improved sleep quality under warm conditions in young adults. Goose down-filled duvets increased slow-wave sleep under cool conditions in young adults. However, a systematic comparison of fibre types is challenging due to the diverse nature of the studies evaluating sleep quality. Further research employing standardised methodologies with standard fibre samples in different populations and in different temperature conditions is imperative to elucidate comprehensively the effects of fibre choices on sleep quality. Despite the limitations and heterogeneity of the included studies, this analysis offers valuable insights for individuals seeking to optimise their sleep experiences and for manufacturers developing sleep-related products.

Managing sleep disruptions during cancer: Practical tips for patient education

Sleep disruptions are commonly reported during and after cancer. In addition to its immediate relevance for patients' immunity and response to treatment, poor sleep can also affect their psychological health and, ultimately, quality of life. Sleep disturbances can also affect caregivers who are supporting cancer patients, adding to their burden. Therefore, it is important for both patients and their families to receive personalized advice and assistance to improve sleep quality. Research has demonstrated that providing intervention for sleep difficulties early in the care trajectory of cancer patients can enhance satisfaction with care and reduce depression. In this article, we will outline basic practical tips that oncology nurses can offer to patients experiencing sleep difficulties, ranging from basic sleep hygiene practices to rearranging their bedroom environment for better rest.

Functional links between thermoregulation and sleep in children with neurodevelopmental and chronic health conditions

The bi-directional relationship between sleep and wake is recognized as important for all children. It is particularly consequential for children who have neurodevelopmental disorders (NDDs) or health conditions which challenge their sleep and biological rhythms, and their ability to maintain rhythms of participation in everyday activities. There are many studies which report the diverse reasons for disruption to sleep in these populations. Predominantly, there is focus on respiratory, pharmaceutical, and behavioral approaches to management. There is, however, little exploration and explanation of the important effects of body thermoregulation on children's sleep-wake patterns, and associated behaviors. Circadian patterns of sleep-wake are dependent on patterns of body temperature change, large enough to induce sleep preparedness but remaining within a range to avoid sleep disturbances when active thermoregulatory responses against heat or cold are elicited (to maintain thermoneutrality). Additionally, the subjective notion of thermal comfort (which coincides with the objective concept of thermoneutrality) is of interest as part of general comfort and associated behavioral responses for sleep onset and maintenance. Children's thermoregulation and thermal comfort are affected by diverse biological functions, as well as their participation in everyday activities, within their everyday environments. Hence, the aforementioned populations are additionally vulnerable to disruption of their thermoregulatory system and their capacity for balance of sleep and wakefulness. The purpose of this paper is to present hitherto overlooked information, for consideration by researchers and clinicians toward determining assessment and intervention approaches to support children's thermoregulation functions and promote their subjective thermal comfort, for improved regulation of their sleep and wake functions.

Effectiveness of a Cool Bed Linen for Thermal Comfort and Sleep Quality in Air-Conditioned Bedroom under Hot-Humid Climate

Comfort temperature and sleep quality involving 20 participants were determined in two cases: Case A (arbitrary, controlled air-conditioner setting) and Case B (adjustment of 3 °C higher than the setting of Case A with cool bed linen). Data of indoor thermal comfort and electricity consumption were collected every night throughout the measurement period. Questionnaires on thermal comfort and sleep quality were distributed twice a night for a duration of three nights for each case; the first night was for respondents’ adaptation and the following two nights were for measurement. The sleep quality of the respondents was objectively measured using a commercially available activity tracker. Results found that most respondents were thermally comfortable in both cases, with 39% lower energy consumption reported for Case B compared to Case A. The thermal conditions of Case B were found to be more tolerable than those of Case A. Most respondents reported to have a calm and satisfied sleep for both cases. Comfort temperature and Sleep Efficiency Index (SEI) were found to be maintained in both cases.

The impact of sleepwear fiber type on sleep quality under warm ambient conditions

BACKGROUND

Sleep disturbance in adults with no health concerns is often linked to the thermal environment. This study assesses the impact on sleep quality of sleepwear made from fibers with different thermal insulation and hygral properties. This randomized cross-over study investigated the effects on sleep quality of sleepwear made from cotton, polyester and Merino wool in adults aged 50-70 years, at an ambient temperature of 30 °C and a relative humidity of 50%.

METHODS

Thirty-six healthy participants completed four nights of sleep study with polysomnography. Participants were categorized by body mass index as <25 kg·m^-2 or ≥25 kg·m^-2, age as <65 years or ≥65 years, and by Pittsburgh Sleep Quality Index (PSQI) as poor sleepers (PSQI≥5) or good sleepers (PSQI<5).

RESULTS

Small, but statistically significant sleep benefits were observed for wool over cotton and polyester sleepwear for multiple sleep parameters, while neither cotton nor polyester was responsible for any statistically significant sleep benefit over the 11 sleep parameters examined. The key findings were: 1) A significant sleepwear effect was observed for sleep onset latency (SOL), p=0.04. 2) For older participants, sleeping in wool significantly reduced SOL (12.4 mins) compared with cotton (26.7 mins, p=0.001) or polyester (21.6 mins, p=0.001). 3) A statistically significant effect was found for sleep fragmentation index (p=0.01) in which wool sleepwear (12.1 no·h^{- 1}) was lower than polyester (13.7 no·h^{- 1}) (p=0.005), but not different to cotton (13.3 no·h^{- 1}). 4) Poor sleepers had less wakefulness when sleeping in wool compared to cotton (p=0.047). 5) And Poor sleepers had higher rapid eye movement sleep latency in polyester than in cotton (p=0.037) or in wool (p=0.036).

CONCLUSION

Statistically significant benefits for wool sleepwear were observed on average for all participants and, in particular, for the older and poorer sleepers. There were no significant differences in any sleep variables between sleepwear types for the BMI sub-group.

Calibration and validation processes for relative humidity measurement by a Hygrochron iButton

Accurate relative humidity (RH) measurement is demanded in studies of thermal comfort. Thermal discomfort occurs when the near-to-skin temperature or RH is outside of the thermal comfort zone. The Hygrochron, a small wireless device which measures both temperature and RH, would be suitable and convenient in exercise or sleep studies. However, the RH measurement has not been validated. This paper has three parts. Part 1: In evaluating the sensor surface for RH detection, four Hygrochrons were placed on a wet paper towel. Two were placed on the towel with the protruding surface facing up and the other two facing down. The results showed that the Hygrochron with the protruding side was the sensor surface for detecting RH. Part 2: Twenty-seven Hygrochrons were calibrated in a humidity calibration chamber at a RH range from 40 to 90% at a constant temperature from 32 to 37°C. The mean bias was -1.08% between the Hygrochrons and the calibration chamber. The Hygrochron overestimated RH at the lower range (40-60%) and underestimated RH at the higher range (80-90%). The application of individual regression equations to each Hygrochron improved accuracy and reduced the mean bias to -0.002%. However, one Hygrochron showed outlier values that may be due to a manufacturing defect. Part 3: The reproducibility of Hygrochron for RH measurements was tested twice at the same condition of 35°C over a three-month interval. The intra-class coefficient was 0.996 to 1.000 with non-significant differences in the mean RH between test and re-test results (p=0.159). Hygrochrons are valid for RH measurements which show high reproducibility. It is recommended that Hygrochrons be calibrated over a range of desired RH and temperature prior to use to improve accuracy and detect any manufacturing defects.

Physiological and Psychological Responses during Exercise and Recovery in a Cold Environment Is Gender-Related Rather Than Fabric-Related

We evaluated gender-specific effects of two types of undergarments on exercise-induced physiological and psychological stress and subsequent recovery in cold conditions for male and female participants. Ten healthy men and eleven healthy women (25.0 ± 1.5 versus 23.4 ± 1.2 years old, respectively) completed the experimental session twice with two different types of undergarments: polyester or merino wool leggings and long-sleeve tops; specifically, merino fabric had greater thermal resistance and water absorbency, and less water vapor as well as air permeability than polyester. Experimental sessions involved performing 1 h of exercise on a cycle ergometer at 8°C ambient temperature and 55% relative humidity, holding at 70-80 revolutions per minute and 60% of each participant's predetermined maximal power output (assessed by maximal oxygen uptake test), followed by 1 h recovery in the same environment. Every 5 min during exercise and every 10 min during recovery, rectal temperature, heart rate, subjective ratings for thermal, shivering/sweating and clothing wetness sensations, and clothing next-to-skin and outer side surface temperature and humidity on the chest, back and thigh were recorded. All participants experienced high physiological stress (assessed by physiological strain index) during exercise. No significant gender differences were found in core temperature or heart rate changes during exercise, but women cooled down faster during recovery. Next-to-skin humidity was similar between genders and different garment sets during exercise and recovery, but such temperatures at the chest during exercise and at the thigh during exercise and recovery were lower in women with both sets of garments. Subjective thermal sensations were similar in all cases. In the last 20 min of cycling, women started to feel wetter than men (P < 0.05) for both garment sets. Shivering was reported as stronger in women in the last 10 min of recovery. Most of the changes in the garment microclimates during exercise and recovery in the cold were associated with gender-related differences rather than with fabric-related differences.