While children spend the rest of the time sitting, one hour of physical activity a day benefit your heart health, British researchers report.

The study found that children and adolescents who were exercising more moderate to vigorous daily than their peers had higher levels of cholesterol, blood pressure and weight, which is important for long-term health.


“Parents, schools and institutions must facilitate and encourage physical activity at least moderate intensity in all children, and worry less total time spent being sedentary, at least on these cardiovascular risk factors,” said study author Ulf Ekelund, group leader of the Epidemiology Program of Physical Activity of the Institute of Metabolic Science, Cambridge, England.

“We showed that increased levels of physical activity at least moderate intensity (equivalent to brisk walking) are associated with [improved] many risk factors for cardiovascular disease, regardless of the amount of time these children spend being sedentary, “he said.

For example, children who were in the most active group had a smaller waist than the least active, he said.

“In adults, this difference is associated with an increase of about 15 percent relative risk of premature death,” said Ekelund.

The type of activity is not important as long as the intensity at least equivalent to a brisk walk, Ekelund said. Among the possibilities are playing outside, biking, dancing, aerobics, walking and playing team sports.

However, the positive benefits of exercise does not necessarily counteract the harmful effects of a sedentary lifestyle, he said. “There may be certain sedentary behaviors like watching television, which pose health risks, and that watching television is associated with other unhealthy behaviors [such as eating between meals]. Therefore, limit the time watching television remains important for the health and welfare of children, “said Ekelund.

The report appears in the Feb. 15 issue of the journal Journal of the American Medical Association .

For the study, researchers collected data from 14 studies involving over 20,000 children between 4 and 18 years old, obtained from an international database on children. A motion sensor measured the total activity and time spent in sedentary, and in moderate-intensity activity and vigorous. There were no specific activities involved.

Overall, three quarters of the children had normal weight, 18 percent were overweight and 7 percent were obese. They spent on average 30 minutes a day in some form of moderate to vigorous exercise, and 354 minutes a day (or almost six hours) sedentary.

Children of both sexes who exercised for more than 35 minutes a day had a blood pressure, cholesterol, blood glucose and triglycerides lower, and were thinner than children who were less than 18 minutes of exercise a day, said Ekelund group.

The average waist size differed by more than two inches between adolescent boys more active and less active. And those with the largest waist circumference at baseline were less active after two years of follow up.

Samantha Heller, exercise physiologist and clinical nutrition coordinator at the Center for Cancer Care at Griffin Hospital in Derby, Connecticut, said “there is absolutely no reason why our children are overweight and sedentary are at risk of cardiovascular disease” .

“The exercise, however, is great for kids, teens and adults,” he said.

Even children who are ineligible for competitive sports have the innate need to be physically active, said Heller.

“Parents and caregivers should limit time spent with technology (like computers, Cases and TV) and let kids be kids, they run and play,” he advised.

Adults also should be involved, said Heller. “They can jump rope, play hide and throw the frisbee with the kids. Children will do better in school, develop social skills, improve coordination, [and] will be happier and healthier.”