Kids' Physical Activity Goal Too Low?

July 20, 2006 -- The government's recommendation for kids' daily exercise may be too low for optimal heart health, a new study shows.

The report, published in The Lancet, suggests kids may need 90 minutes of daily physical activity to help avoid a cluster of heart diseaseheart disease risk factors.

That's 30 minutes longer than the CDC's current recommendation. The CDC says children should get at least an hour of moderate physical activity most days of the week, and preferably daily.

Kids' physical activity needn't be hard-core exercise. Walking and playing will do, note Lars Bo Andersen, PhD, and colleagues. Andersen is a sports medicine professor at the Norwegian School of Sport Sciences in Oslo, Norway.

Also, the findings aren't just for overweight kids. Fitness is the issue, not fatness, a journal editorial notes.

Monitoring Kids' Movement

The researchers studied 915 girls and 817 boys in three European countries: Estonia, Denmark, and Portugal.

The kids were either 9 years old or 15 years old. The researchers chose those ages because they fall either before or after puberty typically starts.

Many studies on this subject rely on kids or parents to report physical activity. But such reports aren't always accurate. So Andersen's team took a different approach.

The researchers gave each child a device called an accelerometer, which tracks physical activity. The kids wore the devices on their hips for two weekdays and two weekend days.

Data was also collected on the kids' height, weight, pubertal status, blood pressure, and skinfold thickness (a gauge of body fat). The kids provided blood samples -- which were checked for cholesterol and triglyceridestriglycerides (a type of blood fat) -- and they took a blood sugar test after fasting.

Big-Time Movers Fared Best

The most active kids in the group were the 9-year-olds who got about nearly two hours per day of physical activity and 15-year-olds who got nearly and hour and a half of daily physical activity.

Those children did moderate and vigorous activity that equaled walking nearly 2.5 miles per hour, the study shows.

Kids who were less physically active were two to three times more likely to have a cluster of heart diseaseheart disease risk factors that included higher blood pressure, poor cholesterol and triglyceride levels, thicker skinfold measurements, and resistance to insulin (the hormone that controls blood sugar).

The researchers aren't saying any of the kids actually had heart disease. But they write that "even if none of the participants had clinical disease, clustered risk is certainly an undesirable condition, and has been shown to track into young adulthood."