Observational study of environmental factors that affect body movement during normal sleep

¹ Yamagata University, Department of Informatics and Electronics Graduate School of Science and Engineering, 4-3-16, Jonan, Yonezawa city, Yamagata, Japan
² Kindai Univ., Faculty of Architecture, 3-4-1, Kowakae, Higashi-Osaka city, Osaka, Japan

^* Corresponding author: ota@j-michishirube.net

Abstract

In this observational study, body movements during sleep were evaluated. Measurements were recorded in the subject's bedroom under the normal conditions. Healthy 8 males and 8 females aged 19-56 years old participated in the experiment. Data for 20 to 30 nights were obtained for each subject and the analysis was conducted using 325 valid data. As a result, there observed significant differences among subjects for body movement and environmental factors. Concerning body movements, the results showed significant differences in gender, age group, group of The General Health Questionnaire's value, and alcohol intake. The regression line between body movement and relative humidity has a negative slope, and 12 out of 15 subjects showed a positive correlation between radiation temperature and the frequency of the body movement. For relative humidity, 3 subjects showed significant correlations with negative slopes. The factors could be categorized into two groups: those based on individual differences and those based on the environment. It was also affected by the factors that varied from day to day. The degrees of mutual influence of these factors on body movement were examined. The results showed that the relative humidity had the highest standardized coefficient for overall sleep duration, followed by gender, radiant temperature of celling, and drinking habit.