The Effects of Moderate Chronic Sleep Restriction on Physical Activity Levels in Older Long and Average Duration Sleepers: A Secondary Analysis

The relationship between sleep and physical activity is an area of growing scientific interest, particularly in the context of older adults. The importance of examining long sleep duration and its influence on physical activity in this demographic becomes increasingly relevant given rising healthcare costs. This dissertation aims to investigate this intricate relationship via secondary analysis by examining the effects of moderate time-in-bed (TIB) restriction (60 minutes per night)) on various intensities of physical activity (sedentary, light, moderate, vigorous, moderate-vigorous physical activity) in older adults classified as long sleepers and average duration sleepers. It was hypothesized that moderate TIB restriction would result in differential changes in physical activity levels across various intensities, with long sleepers exhibiting increased physical activity and average sleepers displaying decreased activity, potentially influenced by alterations in TST (total sleep time) and SE (sleep efficiency). Utilizing a randomized controlled trial design, this study examined the effect of treatment changes in objectively measures activity (waist actigraphy) and subjects physical activity levels as measured by the Godin Leisure-Time Exercise Questionnaire . Eligible participants were long sleepers (sleeping > 9 hours per night) and average sleepers (sleeping 7-9 hours per night). Both types of sleepers were either randomized to TIB restriction or asked to maintain their average sleep patterns. Mean TIB restriction compared with baseline was 39.5 minutes in average sleepers and 52.9 minutes in long sleepers randomized to TIB restriction . Contrary to the original hypothesis, no significant effect of TIB restriction was observed across all physical activity levels in either long sleepers or average sleepers. However, a notable association was found between increased sleep efficiency (+0.09% [SD = ± 4.64%]) and light physical activity (±31 minutes [SD = ± 104.81, R=0.445, P < 0.007]) in long sleepers undergoing TIB restriction. While this study presents several methodological limitations, including its nature as a secondary analysis and the less-than-intended achievement of TIB restriction, it adds a valuable layer to the existing body of research on sleep and physical activity in older adults. The findings suggest that moderate TIB restriction may not be sufficiently impactful to change behavior in physical activity levels, thus highlighting the need for more nuanced, targeted research in this domain.