The estimated impact of reallocating time between sedentary behaviours on behavioural and mental health outcomes

Currently, there is evidence of many health and social benefits from limiting time in sedentary behaviour (SB). However, there is still much research to be done on whether all types of SB are detrimental to all aspects of children’s health. For example, whether watching TV, playing video games, talking on the phone, surfing the internet, or reading all have similar relationships with health and behavioural indicators among children and youth. The objective of this study was to estimate the impact of replacing one time-based SB with another using the isotemporal substitution method (ISM). 5621 total participants (49% boys) in grades 5-12 from PEI schools were given the SHAPES-PEI questionnaire. Students self-reported time spent watching/streaming TV shows or movies, playing video/computer games, talking on the phone, surfing the internet, and reading for fun, as well as the following health outcomes: mental fitness, academic achievement, pro-social behaviour, and bullying. ISM was used to estimate the impact of replacing one time-based SB with another. Results from the ISM indicated that replacing other forms of SB with reading for fun was consistently associated with having high mental fitness, high academic achievement, increased pro-social behaviour, and not bullying others. Replacing other SBs with time spent surfing the internet and talking on the phone were associated with detrimental effects on the above outcomes. Our results suggest that not all forms of SB have similar relationships with health indicators and replacing screen-based SB with reading may have benefits among children and youth.