Sleep timing worsening with age? Visit outdoor-light daily: A cross-sectional study of homemakers and office-going women

The present study depicts differences in sleep behavior, activity, and light exposure of homemakers and office-going women of urban India using a questionnaire survey, actigraphy, and urinary melatonin assay. Self-reported surveys filled by 1316 office-going and 1393 homemaker women (ages 18-79 years) comprised 7 brief questions, viz. body mass index (BMI), work-hours, sleep characteristics etc. We predicted that differences in sleep timings and daily activity patterns of urban Indian women were related to occupational routines, specifically among office-going and homemaker women. Results suggested associativity and relative risk for altered sleep length and recreation with age and occupation. Sleep onset in young and old office-going women was delayed, not in the middle-aged. Objective measurement of sleep, daily activity, and light exposure suggested disrupted Sunday activity than weekdays. Externally managed work-rest cycles in office-goers during weekdays consolidated daily activity patterns. During weekdays, homemakers exhibited greater intraday activity variability. Photometric luminance data using actigraphy revealed homemakers experienced greater exposure to brighter morning light intensities compared to office-going women, although urinary melatonin levels did not differ among groups. The variation in associativity of light-activity during weekdays depicted better light-activity coupling in homemakers. Our observation of delayed sleep onset, in office-goers needs attention because it is an established risk factor to various lifestyle disorders.. Using multimodal methodology of subjective and objective measures, our study validates age-related sleep onset timing, a hidden factor in contemporary health issues.