This may seem like a shocking statement that couldn’t possibly be true… yet recent research indicates that hours spent in sedentary activities like TV watching, computers and video games may be just as detrimental for health as other potent risk factors, regardless of physical activity level (2).
A group in Australia used a life table analysis that compiled research investigating the relationship between TV viewing time and death as well as national population and mortality data (1). What they found was startling – every single hour of TV watched after the age of 25 shortened the viewer’s life expectancy by just under 22 minutes. Alarming to be certain, but what about kids? As today’s children become less active and more overweight, what role does “screen time” play?
TV viewing and computer use (outside of homework time) are associated with a greater risk of childhood overweight and obesity, with greater mortality and weight gain persisting into adulthood (3). Two hours per day of such screen time seems to be the magic number when it comes to risk of obesity in children – body weight and waist circumference increase dramatically as “recreational sitting” time exceeds this cutoff (4), as does risk of psychological difficulties such as peer problems and hyperactivity (5). And this may not be limited to one screen only…
An estimated 20% of childrens’ media viewing is from mobile devices. Many children and adolescents engage in multi-screen viewing, where TV viewing provides the “background” while attention is focused towards a laptop, handheld device or smart-phone – usually to avoid having to watch TV commercials or to keep busy when a program was loading on another screen (6). What about patience as a virtue! Is it that kids today cannot be without stimulation? Is sitting in unfocused silence for 30 seconds so terrible?
What about the mindless eating that frequently accompanies screen time? A recent review provides more proof that couch potatoes have poorer diets. Greater TV viewing was strongly associated with the consumption of energy-dense snacks, drinks and fast food, and a lower consumption of fruit and vegetables in the pooled results of 45 studies (7).
Likewise, the argument that kids don’t really pay attention to junk food ads can be laid to rest. Longer duration of TV watching influenced how often kids consumed soft drinks, snacks and fast foods. Children and adolescents watching two or more hours of TV a day were more than twice as likely to drink soft drinks five times a week or more compared peers watching less TV (8).
Just how is it that kids are spending so much time glued to screens? De Jong et al. (4) evaluated factors, in the home environment, with the greatest influence over TV time. Multi-TV households, having a TV in a child’s bedroom (over 33% of kids have this!) and not having rules around TV viewing were associated with more screen time. Not surprisingly, when parents set limits on screen time, particularly television, sedentary hours and risk of obesity decreased (9). Indeed, how permissive or restrictive parents are in actually enforcing screen time allowances is key (10).
So how do we target these behaviours and change them? The need for parental involvement and buy-in are absolutely essential if screen time is to be successfully reduced. In a meta-analysis of screen time-reducing interventions, strategies such as parental-enforced time restrictions and television-control devices to budget time allotment provided success, though behaviour change was modest at best (11).
Although not specifically targeting screen time, Anderson et al. (9) found that three household routines reduced risk of childhood obesity by more than 40%:
- Regularly eating the evening meal as a family (more than 5 nights per week)
- Obtaining adequate nighttime sleep on weekdays (> 10.5 hours per night)
- Having limited screen-viewing (television, video, DVDs) time on weekdays (< 2 hours/day).
No Baloney’s advice? Promote healthy children and families by eating meals together (not in front of the TV) and participating in physical activities the whole family can enjoy!
1. Veerman JL, Healy GN, Cobiac LJ, Vos T, Winkler EAH, Owen N, Dunstan DW. Television viewing time and reduced life expectancy: a life table analysis. Br J Sports Med 2011. [epub ahead of print]
2. Stamatakis E, Hamer M, Dunstan DW. Screen-based entertainment time, all-cause mortality, and cardiovascular events: population-based study with ongoing mortality and hospital events follow-up. J Am Coll Cardiol 2011; 57:292-9.
3. Thorp AA, Owen N, Neuhaus M, Dunstan DW. Sedentary behaviors and subsequent health outcomes in adults a systematic review of longitudinal studies, 1996-2011. Am J Prev Med 2011; 41:207-15.
4. de Jong E, Visscher TL, Hirasing RA, Heymans MW, Seidell JC, Renders CM. Association between TV viewing, computer use and overweight, determinants and competing activities of screen time in 4- to 13-year-old children. Int J Obes 2011 [epub ahead of print]
5. Page AS, Cooper AR, Griew P, Jago R. Children’s screen viewing is related to psychological difficulties irrespective of physical activity. Pediatrics 2010; 126:e1011-7.
6. Jago R, Sebire SJ, Gorely T, Cillero IH, Biddle SJ. “I’m on it 24/7 at the moment”: a qualitative examination of multi-screen viewing behaviours among UK 10-11 year olds. Int J Behav Nutr Phys Act 2011; 8:85.
7. Pearson N, Biddle SJ. Sedentary behavior and dietary intake in children, adolescents, and adults. A systematic review. Am J Prev Med 2011; 41:178-88.
8. Utter J, Scragg R, Schaaf D. Associations between television viewing and consumption of commonly advertised foods among New Zealand children and young adolescents. Public Health Nutr 2006; 9:606-12.
9. Anderson SE, Whitaker RC. Household routines and obesity in US preschool-aged children. Pediatrics 2010; 125:420-8.
10. Jago R, Davison KK, Thompson JL, Page AS, Brockman R, Fox KR. Parental sedentary restriction, maternal parenting style, and television viewing among 10- to 11-year-olds. Pediatrics 2011. [epub ahead of print]
11. Maniccia DM, Davison KK, Marshall SJ, Manganello JA, Dennison BA. A meta-analysis of interventions that target children’s screen time for reduction. Pediatrics 2011; 128:e193-210.