Purpose: Current sleep hygiene recommendations advise against moderate-vigorous physical activity (MVPA) in the evening; few studies have examined how evening MVPA relates to sleep among youth. We examined associations between evening MVPA (6-10pm) and sleep quality among 12-17-year-olds who met daily MVPA guidelines (60 minutes).
Methods: This cross-sectional study is a secondary analysis of data from the FLASHE (Nebeling et al., 2017) study. Web-based survey data regarding sleep quality and MVPA timing were collected from 1416 US youth who meet MVPA guidelines. Sleep quality (good/poor) was compared between youth who reported participating in evening MVPA at least 1 evening/week versus those reporting no evening MVPA, using covariate-adjusted logistic regressions. Moderation by age (12-14 vs. 15-17 years) was examined.
Results: Most youth (77%) participated in evening MVPA at least 1 evening/week and 87% experienced good sleep quality. Sleep quality did not differ between youth who engaged in evening MVPA vs. those who did not, but only among 12-14-year-olds. Among youth aged 15-17 years, there was a significant positive association between evening MVPA and sleep quality; those who engaged in evening MVPA had 3.35 times the odds of good sleep quality relative to those with no evening MVPA.
Conclusion(s): Our study did not find evidence to restrict opportunities for youth to engage in evening MVPA. In fact, evening MVPA positively relates to sleep quality among older youth. Further work is required to understand the effects of evening MVPA on other objective and subjective sleep attributes.