More high-intensity exercise—and a lot less TV—could protect teens from future CVD

National guidelines recommend teens aim for an hour of moderate to vigorous exercise per day to maintain good health and ensure future wellbeing, but researchers at the University of Exeter in the United Kingdom are saying that might not cut it.

In a study published in the March edition of the International Journal of Cardiology, lead author Alan R. Barker, PhD, and colleagues wrote that moderate exercise, combined with the sedentary habits typical of teenagers, don’t necessarily make the mark for staying healthy.

“Many previous studies have put moderate and vigorous physical activity together when looking at potential health benefits, as this is what health guidelines are based on,” Barker explained in a release from Exeter. “We wanted to separate these and see whether their effects varied.”

And, in a group of 534 European teenagers drawn from the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) trial, they did.

“Moderate activity has many health benefits, but in specific terms of reducing risk factors for cardiovascular disease, it’s vigorous activity that appears to make a difference,” Barker said.

Current U.K. National Health Service guidelines suggest individuals aged 5 to 18 should get in the habit of doing at least 60 minutes of moderate to vigorous activity per day. In Barker and co-authors’ study of adolescents between 12 and 17 years old, though, only vigorous exercise, like team sports, dancing or running around a playground, reduced any cardiovascular risk factors like body mass or waist size.

Moderate activity is defined as using three times the amount of energy an individual would use while sedentary, the study explained. Vigorous activity is defined as expending more than six times that amount.

For their research, Baker et al. analyzed physical activity intensities, sedentary time, TV viewing, cardiorespiratory fitness and muscular fitness in each participant. They found, in addition to their discoveries about exercise intensity, that teens who spent more time watching TV also saw a greater risk for developing diabetes and cardiovascular illness later in life.

“Public health guidelines should prioritize on increasing levels of cardiorespiratory fitness, muscular fitness and vigorous physical activity, and reducing TV viewing time to lower cardiovascular disease risk in youth,”  the authors wrote.