Isotemporal substitution analysis of time between sedentary behavior, and physical activity on sleep quality in younger adults: a multicenter study

To evaluate the effects of replacing time spent in sedentary behavior (SB) with moderate to vigorous physical activity on sleep quality in young adults. Multicenter cross-sectional study, carried out with students enrolled in undergraduate courses at universities in Brazil. Sleep quality was assessed using a question of the World Health Organization Quality of Life (WHOQOL-brief) and classified as good or poor sleep quality. SB was evaluated by self-reported total sitting time, and the level of leisure-time PA was classified according to the intensity of moderate-intensity physical activity (MPA) and vigorous-intensity physical activity (VPA), which were assessed using a self-reported questionnaire. An isotemporal replacement logistic model was used to evaluate the effects of different SB, MPA, and VPA sessions on sleep quality. A total of 8,059 study participants were evaluated, the majority had poor sleep quality (64.79%), were physically inactive (48.28%, defined as practicing < 150 min of MPA or < 75 min of VPA per week), and spent ≥ 9 h/day in SB (55.08%). The multivariate model showed an association between non-adherence to wake-based movement guidelines and poor sleep quality, where those with one altered behavior were 43% more likely to have poor sleep quality (OR:1.43;95%CI:1.27 to 1.60), while individuals with two altered behaviors were 97% more likely (OR:1.97;95%CI:1.73 to 2.24). In the isotemporal analysis, replacing MPA and VPA with equivalent time in SB increased the odds of poor sleep at all times assessed, with peaks of 56% for MPA and 68% for VPA. The results of the present study indicate that replacing SB with the same amount of MPA or VPA may reduce poor sleep quality.