Amount and timing of physical activity in relation to sleep quality in the general middle-aged Dutch population: A cross-sectional analysis

Objectives: To examine whether the amount and timing of moderate-to-vigorous physical activity (MVPA) was associated with sleep quality and duration in the general population. Methods: This is a cross-sectional analysis of data of a Dutch cohort collected between 2008 and 2012. Timing of physical activity (measured using an accelerometer) was categorized as performing most MVPA in morning (06:00-12:00), afternoon (12:00-18:00), evening (18:00-00:00), or even distribution of MVPA over the day (reference). Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). We estimated OR with 95 % CI of a poor score on individual PSQI components and global PSQI score using logistic regression while adjusting for relevant covariates. Results: We analyzed 736 participants, of whom 57 % women, aged 56 (6) years, BMI 26.1 (4.2) kg/m²). Amount of MVPA (hours/day) was associated with lower odds of fatigue-related dysfunction during daytime (OR: 0.54 0.32-0.94), but not with global PSQI score. Participants who performed most MVPA in the morning were less likely to report sleep disturbances (OR: 0.23, 95 % CI: 0.09-0.60), compared to participants with an even distribution of. Timing of MVPA was not associated with global PSQI score nor other components and CI were large. Conclusions: Differences in sleep quality are unlikely to be biological mechanisms underlying the previously shown associations between timing of physical activity and metabolic health.