There is a large body of evidence from all study design s which suggests that decreasing any type of sedentary time is associated with lower health risk in youth aged 5 - 17 years .
In particular , the evidence suggests that daily TV viewing in excess of 2 hours is associated with reduced physical and psychosocial health , and that lowering sedentary time leads to reductions in BMI
Accumulating evidence suggests that , independent of physical activity levels , sedentary behaviours are associated with increased risk of cardio-metabolic disease , all-cause mortality , and a variety of physiological and psychological problems .
Therefore , the purpose of this systematic review is to determine the relationship between sedentary behaviour and health indicators in school-aged children and youth aged 5 - 17 years .
Stability of television viewing and electronic game/computer use in a prospective cohort study of Australian children: relationship with body mass index
Background While much cross-sectional data is available , there have been few longitudinal investigations of patterns of electronic media use  in children . Further , the possibility of a bi-directional relationship between electronic media use and body mass index in children has not been considered . This study aim ed to describe longitudinal patterns of television viewing and electronic game/computer use , and investigate relationships with body mass index ( BMI ) . Methods This prospect i ve cohort study was conducted in elementary schools in Victoria , Australia . 1278 children aged 5–10 years at baseline and 8–13 years at follow-up had their BMI calculated , from measured height and weight , and transformed to z-scores based on US 2000 growth data . Weight status ( non-overweight , overweight and obese ) was based on international BMI cut-off points . Weekly  television viewing  and electronic game/computer use were reported by parents , these were summed to generate total weekly screen time . Children were classified as meeting electronic media use guidelines if their total screen time was ≤14 hrs/wk . Results Electronic media use increased over the course of the study ; 40 % met guidelines at baseline but only 18 % three years later . Television viewing and electronic game/computer use tracked moderately and total screen time was positively associated with adiposity cross-sectionally . While weaker relationships with adiposity were observed longitudinally , baseline z- BMI and weight status were positively associated with follow-up screen time and baseline screen time was positively associated with z- BMI and weight status at follow-up . Children who did not meet guidelines at baseline had significantly higher z- BMI and were more likely to be classified as overweight/obese at follow-up . Conclusion Electronic media use in Australian elementary school children is high , increases with age and tracks over time . There appears to be a bi-directional association suggesting that interventions targeting reductions in either screen time or adiposity may have a positive effect on both screen time and adiposity
There is a large body of evidence from all study design s which suggests that decreasing any type of sedentary time is associated with lower health risk in youth aged 5 - 17 years .
In particular , the evidence suggests that daily TV viewing in excess of 2 hours is associated with reduced physical and psychosocial health , and that lowering sedentary time leads to reductions in BMI
Accumulating evidence suggests that , independent of physical activity levels , sedentary behaviours are associated with increased risk of cardio-metabolic disease , all-cause mortality , and a variety of physiological and psychological problems .
Therefore , the purpose of this systematic review is to determine the relationship between sedentary behaviour and health indicators in school-aged children and youth aged 5 - 17 years .