Chidren's Exercise: How Much Do They Need?

Children need at least 90 minutes of exercise a day to avoid heart disease when they are older, according to a study reported in Lancet (July 23, 2006). The old guidelines recommending 30 minutes of exercise three times a week, or even an hour a day, do not appear to be adequate for preventing obesity and heart disease. Researchers used heart rate monitors to measure the activity of 1700 nine-to-fifteen-year-olds in Denmark, Estonia, and Portugal. They then calculated a heart-attack risk score consisting of blood pressure, cholesterol, insulin resistance, and skinfold thickness.

They compared physical activity from the heart rate monitors with the heart attack risk-factor score and found that the more active the child, the lower the heart attack risk score. Many of the children who exercised for 60 minutes a day were still overweight and had high heart attack risk scores. The authors suggest that the lack of regular physical activity is likely to mean that the children are spending too much time watching TV, playing video and computer games, and eating junk food. There is no reason to expect that the results would be different with American children. The current recommendation of at least an hour per day of moderate activity in children may not be sufficient for future heart health.