Exercise, physical and brain health in relation to sleep in children with overweight or obesity

Zusammenfassung

Background: The prevalence of childhood obesity worldwide is currently at extremely high levels and it is known to be linked to a myriad of health-related problems, among them, a poor sleep health or sleep-disordered breathing. It is important to investigate factors that could fight against obesity consequences and physical exercise emerges as a strong candidate. Objectives and methods: The present International Doctoral Thesis aims to examine the role of sleep-related outcomes in relation to physical and brain health (section 1), to study the effects of a physical exercise program on sleep-related outcomes in children with overweight or obesity (section 2), and to investigate the impact of fatness and cardiorespiratory fitness on sleep-disordered breathing after 1-year of follow-up in children (section 3). Six studies were conducted within the three sections: four cross sectional studies (section 1), one randomized clinical trial (section 2) and one prospective cohort study (section 3). Main findings: Results from this Doctoral Thesis are described below. Television viewing time, cardiorespiratory fitness, and most adiposity markers were associated with sleep-disordered breathing, being the body mass index and television viewing time the best predictors of sleep-disordered breathing in children with overweight or obesity (study 1). Sleep-disordered breathing severity was related to: i) lower school grades (which was driven by inattention/hyperactivity), but not with standardized measurement of academic performance or brain structure (study 2), ii) worse behavioral and emotional functioning (i.e., higher external and internal problems and lower adaptability skills) (study 3), and iii) higher C-reactive protein levels independently of the adiposity levels, but not to other cardiometabolic or inflammatory risk factors in children with overweight or obesity (study 4). This study also suggested that higher levels of cardiorespiratory fitness might attenuate the adverse effect of sleep-disordered breathing on C-reactive protein. In addition, a 20-week physical exercise program reduced the time wakening after sleep onset in children with overweight or obesity in comparison with control group peers, yet effects were not observed on sleep-disordered breathing (study 5). Further, although not statistically significance, all device-assessed sleep outcomes were improved in those days in which the participants attended to the physical exercise session, suggesting acute effects of exercise on sleep-related outcomes. Lastly, severe/morbid obesity, central obesity and low fitness were linked to higher risk of sleep-disordered breathing at baseline in children, but 1-year longitudinal analyses did not show significant associations (study 6). Conclusion: Collectively, the main findings of the present International Doctoral Thesis shed light on the importance of improving sleep-related outcomes in children with overweight or obesity as a strategy to enhance physical and brain health. The use of physical exercise as a tool to improve children’s sleep health and sleep disordered breathing with overweight or obesity is promising and warrants further investigation.