Circadian rhythms and objective measures of physical activity among middle-aged and older adults in Taiwan

Background: To identify the association between daytime activity with objectively monitor and subjective variables at a different time-zone of day as well as the sex differences. Methods: Participants aged 50 years and older living in the community in Taiwan were recruited. The activity was measured by wearable actigraphy devices, diaries, and self-reported questionnaires. The study used nonparametric analysis to examine the association between mean activity level and demographic and subjective measurement variables. Results: Among the 55 participants enrolled in the study, data of 34 (62 %) participants who meet the criteria that wore a wearable actigraphy device for at least 7 completed days were analyzed. There is no significant relationship between each demographics and subjective measurement variables. However, actigraphy counts are significantly related to female's nutrition (Z = -2.367, p = 0.017*), and male's retirement status (Z = -2.132, p = 0.033*). Conclusions: The activity in morning is highest of the day with significant correlation to evening activities. Moreover, actigraphy counts that indicating objective measure of physical activity in female is significantly related to physiological variables (nutritional status), while male are predicted by social variables (retired status).