TV & Heart Disease（II）
The amount of television a person watches is a good index of the overall time they spend sitting, Dunstan says. But there’s also some evidence that watching TV may be unhealthier than other sedentary activities, says Peter Katzmarzyk, Ph.D., an exercise scientist at the Pennington Biomedical Research Center, in Baton Rouge, Louisiana.
“Reading or doing homework doesn’t seem to be associated with risk factors as much as television viewing,” says Katzmarzyk, who was not involved in the study but has studied the health effects of sitting time. “We’re not sure if it’s the sedentary behavior itself or the other things you’re doing during television viewing, like snacking.”
Because the study controlled for diet quality and calorie intake, snacking is unlikely to explain the increased risk of death observed in the study, Dunstan and his colleagues note. However, Dunstan agrees that the combination of inactivity and junk food associated with watching TV certainly has negative health effects.
“Studies show that television leads to an increase in the consumption of energy-dense, snack-type foods,” he says. “It’s a stimulus for poor dietary behavior, whereas some of the other types of sedentary behavior are less likely to stimulate poor snacking behaviors.” And because it burns so few calories — about the same as sleeping, hour for hour — watching TV tends to reduce a person’s overall energy output, Dunstan adds.
Although it’s a handy way to gauge a person’s sitting time, television isn’t the only reason for the decline of everyday movement, Dunstan points out. Technology has made people more sedentary in general. While there are still plenty of occupations that require people to be on their feet all day, more and more of us sit at desks, glued to computer screens. Instead of walking down the hall to speak with co-workers, we email them.
“Modern technology has virtually engineered a lot of incidental, non-sweaty activity out of our lives,” Dunstan says.
Katzmarzyk recommends that deskbound workers stand up and move about whenever they can. “Nobody says you have to sit in front of a computer,” he says. “Get a few books to prop up your monitor and stand up. Stand [while talking] on the phone. Take meetings while you’re walking — anything to get more activity during the day.”
Even watching TV provides opportunities to move around, Dunstan says. Commercial breaks are built-in excuses to stand up and stretch your legs for a minute or two.
The bottom line? Exercise is important for our health, but avoiding prolonged periods of sitting is nearly as important, Dunstan says. The more you move, the greater the health benefits are likely to be. So you can just get up and move about after a while of watching. Don’t be lazy, anyway, health is most important to us.
Watching Too Much TV May Cause Heart Disease?
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