Thank you to Dr. Hugues Sampasa-Kanyinga (MD, PhD Candidate, Epidemiology and Public Health, University of Ottawa) for providing this post.

The Canadian 24-Hour Movement Guidelines for Children and Youth (aged 5–17 years) recommend at least 60 minutes of daily moderate-to-vigorous physical activity,  no more than 2 hours of daily recreational screen time, and 9-11 hours of uninterrupted sleep per night for those aged 5–13 years and 8-10 hours per night for those aged 14–17 years. Spending time outdoors has been identified as an important way for children to meet physical activity recommendations, and it is positively associated with time spent in bed, as well as lower body weight. However, evidence of the benefits of outdoor time on movement behaviours and body weight among adolescents is particularly limited.

Associations between time spent outdoors and movement behaviours (physical activity, sedentary behaviour, and sleep) among adolescents is likely different from that of children for several reasons. For example, children on average spend more time outdoors than adolescents. Compared to children, adolescents engage in more sedentary activities while outside, including but not limited to hanging out with friends, chatting, smoking, using smart phones, etc. Moreover, adolescents are more likely than children to spend a large amount of their time in general sedentary, mainly in the form of screen time behaviours such as electronic media (e.g. smartphone, tablet, and recreational computer) use, TV viewing, and video gaming. Whether the time adolescents do spend being active outdoors is associated with movement behaviours and body composition is unknown.

Thus, the focus of this study was to examine the relationships between frequency of outdoor physical activity after school, adherence to the physical activity, screen time, and sleep duration recommendations, and overweight/obesity among adolescents.

In this study, the authors used data from over 10,000 middle and high school students from 214 schools across the province of Ontario, Canada. Frequency of physical activity outdoors after school was measured using a question that asked how many of the last five school days students were physically active outside after school, such as playing games or sports. Students also self-reported time spent doing physical activity, screen time, and sleep duration, as well as their height and weight. Results of the study showed that more weekdays spent physically active outdoors after school was associated with greater adherence to the physical activity and screen time recommendations and less risk of overweight/obesity. Among the three components of the 24‐hour movement guidelines examined in the present study, frequency of outdoor physical activity was most strongly associated with adherence to the physical activity recommendation. Outdoor physical activity after school on all 5 days was associated with greater odds of adherence to the sleep duration recommendation among males, but not females. Collectively, these findings suggest that more frequent outdoor physical activity after school is associated with better adherence to the physical activity, screen time, and sleep duration recommendations and healthy weight among adolescents.

These findings support previous observations and suggest that outdoor physical activity after school could be an important behavioural target to increase adherence to the 24-hour movement guidelines, particularly the physical activity and screen time recommendations, and may be a way to prevent excess weight gain among adolescents. Although the findings of this study provide important information about the benefits of outdoor physical activity after school among adolescents, causality among observed associations should not be inferred given the cross-sectional nature of the data. Replication studies are needed to confirm these findings. Nevertheless, parents should encourage adolescents to engage in physical activity outdoors after school.

The original article can be accessed here.

Dr. Hugues Sampasa-Kanyinga, MD, MSc. is a PhD candidate in Epidemiology and Public Health at the University of Ottawa and his primary research focus is on 24-hour movement guidelines and mental health in children and adolescents. Dr. Sampasa-Kanyinga works under the supervision of HALO Scientist Dr. Jean-Philippe Chaput.