Repeated device-based measures of daily movement, sedentary behavior, and sleep at 6 months postpartum: the Pregnancy Environment and Lifestyle Study-2 cohort.

Abstract

Study objectives: Appropriate duration and high-quality sleep is essential for overall well-being and may be improved through engaging in daytime physical activity (PA). Yet the postpartum period is a particularly challenging time for these health behaviors, and sleep in this population has received little attention in scientific literature. This study examined the associations of daily PA and sedentary behavior (SED) with postpartum sleep measures, both obtained from wrist-worn ActiGraph devices.

Methods: Data come from the Pregnancy Environment and Lifestyle Study-2 cohort, a racially and ethnically diverse longitudinal cohort of postpartum mothers who delivered at Kaiser Permanente Northern California in 2018-2019. Participants (N = 136) wore ActiGraph wGT3X-BT devices on their non-dominant wrists for 7 days at 6 months postpartum. ActiGraph data were processed in RStudio using validated algorithms for device wear time, PA metrics (i.e. minutes of moderate-to-vigorous physical activity [MVPA], light physical activity [LPA], and SED, bedrest), and sleep quality metrics (i.e. nightly sleep duration; frequency of sleep interruptions; sleep efficiency [defined total nocturnal sleep/total sleep period × 100%]; and average duration of sleep interruptions). We estimated associations using mixed-effects models in SAS, adjusted for participant characteristics and daytime bedrest.

Results: Participants engaged in a median of 66 min/day (Q1-Q3: 36.0-101.0) of MVPA and 340.0 min/day (Q1-Q3: 272.0-422.0) of SED; neither were associated with sleep duration. In the adjusted model, for every additional 10 min of daily LPA, there was 0.12 per cent higher sleep efficiency; in contrast, every additional 10 min of SED was associated with 0.10 per cent lower sleep efficiency (both p < .05). For each additional 10 min of daily MVPA, LPA, and SED, the average length of sleep interruptions was 0.65 min shorter, 0.52 min shorter, and 0.36 min longer, respectively (all p < .05).

Conclusions: More daytime PA, regardless of intensity, may modestly improve sleep quality, while more daytime SED may diminish sleep quality at 6 months postpartum.