Activity mix hikes obese teens’ weight loss: study

Canadian research shows that obese teenagers lose more weight when they alternate aerobic exercise and resistance training rather than just doing one or the other. Scientists have long known physical activity can help people lose weight, but the study out of the University of Ottawa suggests the kind of activity can make a substantial difference.

A group of 304 obese teens between the ages of 14 and 18 were studied over 22weeks. They were divided into four groups, one of which did no exercise. Those in the other three groups were provided different workouts to do four times a weeks and they lost weight.

Those assigned aerobic-only workouts lost 4 cm from their waist size. Those who did resistance training lost 5 cm. But the teens who did both types of activity lost 7cm.

‘Significant differences’

“These differences are significant,” says Glen Kenny, a professor of physiology at the University of Ottawa and lead author of the study. “When you think about it, weight circumference is somewhat of an indicator of risk for disease. It tells us that there was a greater overall improvement.” Recent studies have linked larger waist measurements with higher risks for developing diabetes and cardiovascular diseases such as heart attack and stroke.

‘Overall functional ability…important’

“You have to realize it’s not just about the physical changes in terms of per cent body fat. It’s also about the effects it has on the overall ability, that functional capacity of that individual,” says Kenny. He  notes that at the beginning of the study many of the teens could only achieve a fast walking pace, but by the end of it, could comfortably do some moderate intensity jogging for a prolonged period.

“Those are important changes…You want to maintain that high level of physical activity because when you get into your late twenties things start to deteriorates,” says Kenny. “So having a higher functional capacity at a very early age and maintaining that is critically important.