Sex Differences in the Effect of Physical Activity on Teen Sleep Patterns

Introduction: Insufficient sleep durations, irregular sleep patterns, and poor sleep quality predict obesity including adverse changes to obesity-related outcomes like decreased physical activity (PA). In turn, increasing PA positively impacts sleep durations and quality. The transition from childhood to adolescence brings a decrease in PA with females showing a more significant decrease. This decrease in PA may be a contributing factor to the high rates of insufficient sleep and irregular sleep patterns in teens. To better understand these connections, we examined how PA influenced sleep duration and quality in teens. We expected that higher PA durations would predict longer sleep durations, more regular sleep patterns, and better sleep efficiency. We also explored sex differences to better understand how these connections play out during adolescence. Methods: Current analyses utilized baseline data from the initial week of a larger project (PI: Roane) that examined sleep and obesity-related behaviors in teens. Teens and caregivers provided informed consent/assent. Teens were given activity monitors to continuously capture sleep and physical activity. After one week, height and weight were measured for BMI %tile calculation. Sleep duration, sleep efficiency (SE), and physical activity were calculated from retrieved activity monitor data. Regression analyses examined mean physical activity duration as a predictor with BMI %tile as a covariate for (a) mean sleep duration, (b) sleep duration variability, (c) mean sleep efficiency, and (d) sleep efficiency variability. Results: Teens (n=26) were age 15 years, 27% Hispanic, 42% African American, and 73% female. Mean BMI %tile was 65th (female[f]: 71st, male[m]: 48th) and PA duration was 91 min (f: 82, m: 117). Mean sleep duration was 433 min (f: 429, m: 444); sleep duration variability was 78 min (f: 79, m: 74); SE was 95 (f: 95, m: 93); and SE variability was 5 (f: 5, m: 5). Regression analyses found PA duration predicted mean sleep duration. Analyses by sex indicated PA duration accounted for 74% of the variance in sleep duration for males only. All other findings were not statistically significant. Conclusions: Our analysis showed higher PA predicted longer sleep duration in males. These data provide further support for sex driven differences in how sleep contributes to obesity. Further study with a larger sample is warranted to better understand sex differences in the connection between sleep and obesity.