The relations between sleep, time of physical activity, and time outdoors among adult women

Abstract

Physical activity and time spent outdoors may be important non-pharmacological approaches to improve sleep quality and duration (or sleep patterns) but there is little empirical research evaluating the two simultaneously. The current study assesses the role of physical activity and time outdoors in predicting sleep health by using objective measurement of the three variables. A convenience sample of 360 adult women (mean age = 55.38 ±9.89 years; mean body mass index = 27.74 ±6.12) was recruited from different regions of the U.S. Participants wore a Global Positioning System device and ActiGraph GT3X+ accelerometers on the hip for 7 days and on the wrist for 7 days and 7 nights to assess total time and time of day spent outdoors, total minutes in moderate-to-vigorous physical activity per day, and 4 measures of sleep health, respectively. A generalized mixed-effects model was used to assess temporal associations between moderate-to-vigorous physical activity, outdoor time, and sleep at the daily level (days = 1931) within individuals. There was a significant interaction (p = 0.04) between moderate-to-vigorous physical activity and time spent outdoors in predicting total sleep time but not for predicting sleep efficiency. Increasing time outdoors in the afternoon (versus morning) predicted lower sleep efficiency, but had no effect on total sleep time. Time spent outdoors and the time of day spent outdoors may be important moderators in assessing the relation between physical activity and sleep. More research is needed in larger populations using experimental designs.

Sedentary behaviour and sleep problems among 42,489 community‐dwelling adults in six low‐ and middle‐income countries

“…This could mean that addressing mental and physical health problems may only have a rather minimal effect on improving sleep in people who are sedentary, and that the link between sedentary behaviour and sleep problems may be better explained by other pathophysiological mechanisms. For example, it is known that being physically active instead of being sedentary is implicated in a range of physiological changes, including potential alterations of circadian rhythms (Aoyama & Shibata, ; Murray et al., ). Being active may acutely (i.e.…”

Physical activity and sleep problems in 38 low- and middle-income countries

“…We hypothesize that the relationship between physical activity and sleep is influenced by underlying neurobiological mechanisms which were not assessed in the current study. For example, it is known that exercise, or a structured form of physical activity, is implicated in a range of physiological changes, including potential alterations of circadian rhythms [49,50]. Several studies have observed that moderate to vigorous intensity exercise may acutely (i.e., within minutes) alter melatonin levels and result in a shift of the onset of nocturnal melatonin.…”

“…A C C E P T E D ACCEPTED MANUSCRIPT [53]. Other factors to consider include time spent outdoors [50] and light exposure [54] as potentially moderating the association between physical activity levels and presence of sleep problems via circadian-driven aspects of sleep. However, to the best of our knowledge no previous study on the effects of a physical activity intervention on sleep outcomes has tested, or controlled for, increased exposure to light arising from increased time spent being physically active outdoors.…”

Duration or Timing? What is the Optimal Core for Older Adults to Engage in Moderate-to-vigorous Physical Activity to Prevent Disability?

“…18:01-24:00 based on previous studies [13,19,20]. We calculated the percentage of the three time intervals of MVPA engagement for each participant.…”