A new study about the relationship between TV-watching habits and children’s physical fitness might make you want to yank your kids away from the television.
The research, published in the International Journal of Behavioral Nutrition and Physical Activity on Sunday, found that children who spend more time in front of a screen as preschoolers tend to have larger waistlines and worse muscular fitness as they grow.
Researchers followed 1,314 Canadian children, measuring their TV consumption at 29 and 53 months and testing physical fitness in the second and fourth grades to see if the scale of earlier television viewing had a measurable impact.
Participants watched an average of 8.82 hours of television per week at 29 months and 14.85 hours per week at 53 months. Viewing estimates were supplied by the participants’ parents.
The study cites the American Academy of Pediatrics’s recommendation that children watch two hours of TV per day at most after age 2 (and as little TV as possible before).
Subjects who watched more TV than their fellow participants at 29 and 53 months performed less well on a test of “explosive leg strength” in second grade; their waistlines also grew more dramatically, with kids gaining 0.047 cm by the fourth grade “for every hour increase in weekly television viewing between the ages of 29 and 53 months.” For the average participant, that meant “an expected .41 cm increase in waistline measurement" -- just over the width of four credit cards -- "by age 10." (While "the observed effect sizes per hour of television exposure are small," the study notes, it is nonetheless important to consider "the cumulative effects of excessive television exposure.")
In a Standing Long Jump test, second graders fell behind by .361 cm for every hour of TV they had watched per week as 29-month-olds; for every additional hour they watched between 29 and 53 months, they lost another .285 cm.
The study adds that children’s leg strength and waist circumference can have long-term health consequences: “In particular, child and adult intra-abdominal fat measured by waist circumference independently predict cardiovascular health, development of metabolic syndrome, and insulin resistance.” As far as explosive leg strength is concerned, “projected into adulthood, individual differences in muscular fitness are associated with less back pain, better cardiovascular health, and decreased mortality.”
TV-watching can also encourage other behaviors (e.g. “screen-time snacking”) that lead to weight gain, the study says. The authors suggest that children who see TV commercials for fast food may be more likely to pick unhealthy snack options.
Another recent study explored the negative impact of TV consumption on preadolescents. As HuffPost reported in June:
A study conducted by Indiana University found that TV viewing can alter children's self esteem. White girls and black boys and girls tend to feel worse about themselves after viewing various forms of electronic media. However, white boys are in luck, TV viewing actually increases their self confidence.
Although TV can be a useful tool in the parent's arsenal -- HuffPost blogger Rhiana Maidenberg lists five reasons parents might find it useful (example: it can be a lifesaver on long plane trips) -- the study's lead author says parents should be careful to limit their children's exposure. Dr. Caroline Fitzpatrick said in a press release: “TV is a modifiable lifestyle factor, and people need to be aware that toddler viewing habits may contribute to subsequent physical health."
How much television do your children watch? Is this study likely to change your attitudes to TV time? Let us know in the comments below.