Effect of bedroom environment on sleep and physiological parameters for individuals with good sleep quality: A pilot study

Bedroom conditions affect sleep, overall health, and well-being. Field studies reporting measurements of bedroom environment and sleep parameters are almost lacking in the scientific community since the majority of research has been conducted in laboratories. To fill this knowledge gap, we have investigated the associations among bedroom environmental factors (temperature, humidity, CO2, pressure), measured sleep and physiological parameters (heart rate, heart rate variability, and breathing rate) in participants with good sleep quality. Six subjects were enrolled in the study, possessing a minimum of two years of experience in using the wrist actigraph chosen for the experimentation, and exhibiting good sleep quality. The air quality measurements were conducted using the air quality monitor, whereas advanced actigraphs were employed for the assessment of various sleep stage durations. The statistical analysis, carried out applying Linear Mixed Models, revealed that an increase of 100 ppm of CO2 concentration levels is associated with an approximate 0.29 % decline in sleep quality whereas, concerning the effect of the relative humidity, we observed a 0.1 % reduction in sleep quality associated with a 1 % rise in RH. On the other hand, a 1 °C rise in air temperature is associated with an approximate 0.16 % reduction in sleep efficiency, and, at a CO2 concentration of about 900 ppm, the autonomic nervous system (ANS) indicator remains positive for temperature values < 20 °C. These results contribute to mounting evidence underscoring the crucial role of the bedroom atmosphere in facilitating high-quality sleep.