A new study suggests that obese teens can reverse early signs of artery disease by exercising even if they do not lose weight.
The study, published in the May 19 issue of the Journal of the American College of Cardiology, found that exercise reversed the negative effects of obesity and it did so without changing body weight—presenting a method to improve children's artery health without medications.
First study of its kind
Scientists tested blood vessel function in 19 obese and 20 lean adolescents before and after they participated in an exercise program. The youth were all healthy nonsmokers who had normal cholesterol and blood pressure.
The study focused on flow-mediated dilation, which measures how well the endothelium—the lining of the blood vessel—acts to keep blood moving by widening the vessel. Poor endothelial function is suspected of being an early sign of artery disease. Researchers noted that until this study no one had examined whether exercise can improve endothelial function in obese teens.
For 8 weeks, participants completed three one-hour sessions of aerobic activity and weight training.
Blood vessel function improved significantly
At the start of the study, obese adolescents had impaired endothelial function compared with their lean peers. But blood vessel function had improved significantly by the end of the exercise program.
Obese teens who did not change their diet did not lose weight while on the exercise plan. But they did experience healthy changes in their body composition, including increased muscle mass. They also experienced a decrease in fat around the abdomen. This type of fat is strongly associated with an increased risk of cardiovascular disease.
Teens must stay active to stay healthy
But to keep vessels healthy, teens have to stay active. Exercise quickly improved blood vessel function, but these benefits soon dissipated once teens stopped exercising.
The researchers are currently studying the effects of different types of exercise in obese children and teens to identify the best way to improve blood vessel health and reduce the risk of future cardiovascular disease.
1. K. Watts; Beye, P., Davis, E.A., Green, D.J., Jones, T.W., O’Driscoll, G., Siafarikas, A., “Exercise Training Normalizes Vascular Dysfunction and Improves Central Adiposity in Obese Adolescents,” Journal of the American College of Cardiology, 43: 10: 2004.