Sustained exercise seen best for kids' weight

Longer bouts of exercise may be better for maintaining a healthy weight in children than is sporadic activity accumulated throughout the day, a new study suggests.

The study of some 2500 youngsters 8 to 17 years old found that the more moderate-to-vigorous exercise they got, the less likely they were to be overweight. However, the manner in which they got that exercise also mattered.

The more sustained bouts of 5 to 10 minutes of activity that the kids got each day, the lower were their odds of being overweight -and the benefit was independent of the total time they spent being active per day.

Even among children who had relatively high activity levels, those who had the most bouts of sustained exercise were 59 percent less likely to be overweight than their peers who mainly got sporadic activity lasting less than 5 minutes at a time.

The findings are published in the American Journal of Preventive Medicine.

U.S. guidelines recommend that children get 60 minutes of moderate-to- vigorous exercise each day. They do not specify how those minutes should be accumulated, however.

The current findings suggest that, for weight control, children should strive for more prolonged bouts of activity, according to Dr. Ian Janssen, of Queen's University in Ontario, Canada.

In some cases, he told Reuters Health, organized sports or other activities are the best way to achieve that.

However, Janssen pointed out, not all sports are created equal. He noted that baseball, for instance, typically involves a lot of standing around. Soccer, on the other hand, requires kids to run from one end of the field to the other for sustained periods.

It's not clear why bouts of activity seem beneficial independent of the total time kids spend exercising, according to Janssen. He speculated that more-prolonged exercise might have more pronounced hormonal effects compared with sporadic activity accumulated over the day.

SOURCE: American Journal of Preventive Medicine, May 2009.