PURPOSE:To determine how combinations of physical activity (PA), sedentary behaviour (SB) and sleep are associated with important health indicators in children and youth aged 5-17 years.
METHODS: MEDLINE, EMBASE, SPORTdiscus, CINAHL and PsycINFO were searched for studies examining the relationship between time spent engaging in different combinations of PA, SB and sleep with adiposity, cardiometabolic biomarkers, and physical fitness. Meta-analyses were planned for all outcomes; however, this was precluded due to the high levels of heterogeneity across studies. Therefore, narrative syntheses were employed for all health indicators. The quality of evidence was assessed using the GRADE framework.
RESULTS: 13 cross-sectional studies and 1 longitudinal study reporting data from 36,560 participants met the inclusion criteria. Children and youth with a combination of High PA/High Sleep/Low SB had more desirable measures of adiposity (e.g. a 2.39 kg/m2 lower fat mass index, and an 8-fold reduction in the odds of obesity, p<0.05) and cardiometabolic health (e.g. a 3.31 unit lower metabolic syndrome score, p<0.05), compared to those with a combination of Low PA/Low Sleep/High SB. Health benefits were also observed for those with a combination of High PA/High Sleep (cardiometabolic health and adiposity) or High PA/Low SB (cardiometabolic health, adiposity and fitness), compared to Low PA/Low Sleep or Low PA/High SB. Of the 3 movement behaviours, PA (especially moderate-to-vigorous PA) was most consistently associated with desirable health indicators. Given the lack of randomized trials, the overall quality of the available evidence was low.
CONCLUSIONS:School-aged children and youth characterized by High PA/High Sleep/Low SB have more desirable measures of adiposity and cardiometabolic health, compared to those with a combination of Low PA/Low Sleep/High SB. Further, those with High PA/High Sleep, and High PA/Low SB are also likely to experience health benefits, when compared to Low PA/Low Sleep, or Low PA/High SB.
FUNDING: This project was made possible through funding from the Canadian Society for Exercise Physiology, Conference Board of Canada, Healthy Active Living and Obesity Research Group at the CHEO Research Institute and the Public Health Agency of Canada.