More exercise beats less TV for growing healthier kids

April 27, 2013, MedPage Today

By Charlene Laino

When it comes to improving kids’ heart health, which is more important? Exercising more or sitting around less?

The answer, according to a study that tested youngsters in a real-world setting, is exercising more.

The researchers studied 536 white children ages 8-10 who had at least one obese biological parent. The goal was to examine the combined associations between time spent in moderate- to vigorous-intensity physical activity and time spent in sedentary activities in relation to cardiometabolic risk factors.Results showed that higher levels of physical activity were associated with significantly lower waist circumference, fasting triglycerides, and diastolic blood pressure, and with higher HDL cholesterol, regardless of sedentary time.

In linear regression, moderate- to vigorous-activity was inversely associated with waist circumference and diastolic blood pressure.

In contrast, sedentary time was positively associated with diastolic blood pressure but after adjustment for moderate to vigorous activity, the association was no longer statistically significant.

Self-reported screen time was positively associated with waist circumference and negatively associated with HDL cholesterol independent of moderate to vigorous activity.

“As far as cardiometabolic health is concerned, it’s much better to break a good sweat – even if you sit around a lot,” said first author, Jean-Philippe Chaput, Ph.D., of the University of Ottawa.

That said, when it comes to sitting around, it turns out that so-called “screen time” – time spent playing video games or watching TV, for example — is worse for childhood cardiometabolic health than other types of sedentary behaviors such as reading or just relaxing, he said.

That’s because studies have shown that kids tend to eat more, particularly junk food, when in front of a screen, Chaput said.

The study, by a team from five Canadian hospitals, was published online in Applied Physiology, Nutrition, and Metabolism.

Among other findings:

  • Overall, 44 percent of the children were overweight or obese.
  • When calculated as a mean for the entire sample, only 25 percent of the children met the recommendation for getting at least 60 minutes of exercise a day vigorous enough to get the heart rate going.
  • However, the proportion that accumulated at least 60 minutes of moderate to vigorous physical activity at least six days a week — the current guideline for children and youth in Canada — was substantially lower, at approximately 5 percent.
  • Based on self-reported data, 40 percent of the kids met the guideline for screen-time use of no more than two hours a day. Screen time represented 55 percent of total sedentary time in this sample of children.

“Although results in this study suggest that in children, time spent in moderate to vigorous physical activity appears more important than time spent in sedentary activities, with regard to cardiometabolic health, both increasing children’s participation in physical activity and reducing their screen-related sedentary time are important public health targets to achieve,” Chaput concluded.

Commenting on the findings, Naveen Uli, M.D., of University Hospitals Rainbow Babies & Children’s Hospital, said the study was particularly noteworthy for “providing the first real-world picture of what is going on with exercise and cardiometabolic health in North American children.”

The big question, of course, is how to get children away from the computer and back onto the playing fields.

Uli suggested that parents encourage their children to work in extra exercise whenever they can, whether by doing active chores or joining organized activities like Little League.

Chaput added that any such program designed to increase childhood activity should be “a family affair.” If a parent is physically active, the child is more likely to be physically active.

But if the child goes home and sees his parents sitting around in front of the TV, even organized sports will have little long-term impact on their heart health,” he said.

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