BACKGROUND: Adolescents are recommended to achieve ≥ 60 min/day of moderate-to-vigorous physical activity (PA) and ≤2 h/day of screentime (ST). This study examined the relationships between the use of social networking sites (SNSs) and adherence to PA and STrecommendations in a large sample of Canadian adolescents. METHODS: This cross-sectional school-based survey included a representative sample of 9388 students in grades 7 to 12 across Ontario, Canada. RESULTS: After adjustment for several confounding variables, results showed that male adolescents who use SNSs for fewer hours (≤ 1 h/day) had greater odds of adherence to PA and to both PA and ST recommendations concurrently, while those who use it for more hours (≥ 3 h/day) had lower odds of adherence to the ST recommendation. Female adolescents who use SNSs for more hours had lower odds of adherence to the ST recommendation (use of SNSs ≥ 2 h/day) and to both PA and ST recommendations concurrently (use of SNSs ≥ 5 h/day). CONCLUSIONS: Heavy use of SNSs has a negative influence on the adherence to the ST recommendation in both males and females; however, infrequent use of SNSs was related to the adherence to the PA recommendation and concurrent adherence to both recommendations in males only.
