To follow up on yesterday’s post regarding sedentary behavior (primarily TV viewing) and health, I thought I’d mention Dave Munger’s recent online report for Seed Magazine in which he describes other research on this topic.
First, he talks about a study published in October in the International Journal of Obesity:
The researchers conducted a phone survey of 10,000 Americans who ranged from normal weight to obese. As you might expect, people who engaged in a lot of physical activity tended to weigh less than those who did not.
But when the researchers considered how much time these individuals spent watching TV and movies, a different pattern emerged. No matter how much TV they watched, if they didn’t exercise, they had high BMIs (body mass index — a measure of obesity). But even among people who exercised more than an hour a day, those watching more than an hour of TV per day had significantly higher BMIs than those who did not. In fact, for respondents who watched more than an hour of TV, whether or not they exercised no longer predicted BMI.
Of course, as Munger, points out, this study (like the one I reported on yesterday) shows only a correlation, not a cause-and-effect relationship between TV viewing and being overweight despite exercising daily.
Background TV and kids’ activity
Another study described by Munger offers a warning to parents. Published in Child Psychology, it showed how just having the TV on in the background while children are playing affects their physical activity:
Fifty children, aged one through three, played by themselves in a room while a parent sat nearby reading magazines. Half the time (either at the beginning or end of the session), an episode of the game show Jeopardy! was playing in the background. The researchers videotaped the kids’ playing behavior and found that play episodes and focused attention were shorter while the TV show was on, even though no one was actively watching the show. Over a lifetime, this might mean that these kids are less able to focus on tasks — meaning that, even if they do exercise each day, they’re less likely to do so rigorously enough to burn excess calories.
Other studies have shown that young kids who exhibit less-focused play episodes develop behavioral problems later on. Overall, while much more work still needs to be done, there’s considerable evidence that TV-watching may lead to passivity, which in turn leads to poorer health.
Not all bad
TV viewing offers some benefits, too. As Munger points out, one study found that people feel less lonely while watching TV. And by providing greater access to information, TV may have the power to induce social change. A study in India “found that shortly after the introduction of TV into a village, the standing of women improved dramatically. Villagers were more likely to say it was wrong for a husband to beat his wife, and women had greater autonomy and lower rates of pregnancy,” Munger writes.
TV, thus, presents a paradox. “While [it] may be harmful to an individual’s mental and physical wellbeing,” says Munger, “on the aggregate it could be beneficial to society. Perhaps, as with so many other things, the best advice might be to watch TV — but only in moderation.”
NOTE: Munger and his wife, Greta, a professor of psychology at Davidson College, announced yesterday that they’re ending, after a five-year run, their excellent blog, Cognitive Daily. It will be missed.