Over and over again we’ve all heard about the epidemic of obesity. Less often mentioned is an epidemic of “unfitness” among adolescents.

A report issued in December described an analysis of fitness in more than 3,000 adolescents and about 2,200 adults ages 20 to 49. Nearly 34 percent of the adolescents and about 14 percent of the adults failed submaximal treadmill fitness tests. More adult women than men were unfit (out of shape).

Quite frankly, based on the prevailing lack of physical activity among adults, I was shocked to read that over 80 percent of them appeared fit in this study. One explanation may be the researchers’ generous definition of “fitness” based on a submaximal exercise test.

Exercise can lower the risk of heart disease directly by strengthening the heart  as well as indirectly by helping to prevent obesity. Although all study participants were free from recognized heart disease, I was not surprised to learn that those in the low-fitness group were significantly more likely than their fitter counterparts to have cardiovascular risk factors like hypertension, high blood cholesterol, and being overweight.