Abstract

The prevalence of childhood obesity has increased almost threefold over the past two decades. Shorter sleep duration has been linked to greater body mass index and obesity, both cross-sectionally and in prospective longitudinal studies. Sleep loss has been found to be related to autonomic dysfunction. As well, obese youth exhibit markers of autonomic dysfunction characterized by reduced heart-rate variability (HRV). The aim of the present study was to investigate whether autonomic dysfunction is a pathogenic mechanism that mediates the association between shorter sleep duration and childhood obesity. Participants included 122 youth (50.8% females) aged 8-17 years ( M =12.79, SD =2.19). Youth wore an ambulatory monitor for 24-hours to assess HRV derived from continuous ECG recordings. They also completed an in-home polysomnograph sleep study ( n =57) to assess objective sleep measures (e.g., fragmented sleep, sleep efficiency, and time spent in REM sleep). Subjective sleep measures (e.g., sleep duration, daytime sleepiness, and sleep quality) were obtained by child- and parent-report on validated questionnaires. Shorter sleep duration and poorer sleep quality were found to be associated with greater adiposity. Autonomic dysfunction, as characterized by reduced HRV and parasympathetic activity also was found to be associated with greater adiposity. However, autonomic dysfunction was not found to mediate the association between sleep and obesity. Future research should aim to better understand the role of autonomic dysfunction and its other indices (e.g., blood pressure), as well as hormonal and endocrine function across the course of sleep, as potential pathogenic mechanisms underlying the association between sleep and obesity in youth.