Time spent outdoors and sleep normality: A preliminary investigation

INTRODUCTION: Sleep deficiency is associated with health risks, and time outdoors is related to health benefits. This study assessed time outdoors and its association with sleep normality. METHODS: As part of a health study in Louisville, Kentucky, 735 participants completed questionnaires on their health status, behaviors, neighborhoods, and demographics in 2018–2019. The measures included information on sleep, time outdoors, and mental and physical health. Participant characteristics were assessed by dichotomized sleep normality (N=728), and logistic regression (N=709) examined potential associations between time outdoors and sleep. RESULTS: As time spent outdoors increased from ≤4 hours to >4 – ≤8 hours (OR=1.04; 95% CI: 0.65–1.64) and >8 – ≤12 hours (OR=1.17; 95% CI: 0.63–2.17), odds of normal sleep increased; however, those who spent >12 – ≤16 hours (OR=0.63; 95% CI: 0.31–1.27) or >16 hours (OR=0.83; 95% CI: 0.45–1.53) outdoors had a lower likelihood of normal sleep. No associations between time outdoors and sleep were significant. There was a significant trend of less bodily pain associated with normal sleep (p<0.001) and in the association of depression and sleep, where odds of normal sleep decreased as depression severity increased (p<0.001). CONCLUSIONS: Consistent with extant literature, findings indicate associations between less pain and increased odds of normal sleep and between higher severity of depression and lower odds of normal sleep. Findings for an overall association between time outdoors and sleep normality were not significant. Future work should seek to better explicate the predictor variables to assess how greenness and activity type shape associations with sleep.