Kids these days may be less fit than their parents were at their age, according to a new study.
Research presented at a meeting of the American Heart Association showed that kids today are unable to run as far, or as fast, as their parents were when they were the same age. And cardiovascular fitness-wise, they are 15 percent less fit than their parents were.
"Young people can be fit in different ways. They can be strong like a weightlifter, or flexible like a gymnast, or skillful like a tennis player. But not all of these types of fitness relate well to health," study researcher Grant Tomkinson, Ph.D., a senior lecturer at the University of South Australia's School of Health Sciences, said in a statement. "The most important type of fitness for good health is cardiovascular fitness, which is the ability to exercise vigorously for a long time, like running multiple laps around an oval track."
The findings -- which have yet to be published in a peer-reviewed journal, and thus should be regarded as preliminary -- are based on data from 50 studies on cardiovascular endurance. The studies were published between 1964 and 2010, and included data from 25 million 9-to-17-year-olds around the world.
Over that 46-year period, researchers found that cardiovascular endurance decreased, with some countries experiencing greater decreases than others. In the United States, in particular, it fell 6 percent per decade, on average, from 1970 to 2000 -- greater than the decline in endurance of 5 percent per decade for all 28 countries included in the study.
Researchers also found that kids today run a mile slower -- by a minute and a half -- than their same-age counterparts from 30 years ago.
According to the Centers for Disease Control and Prevention, kids should get at least one hour of physical activity a day, including aerobic exercise (such as running), muscle-strengthening exercise (such as pushups or gymnastics) and bone-strengthening exercise (such as jump-roping or running).