A large global study presented recently at the American Heart Association's Scientific Sessions 2013 meeting confirmed what many have suspected: Worldwide, the current generation of children are less physically fit than their parents.

Children no longer run as far or as often as kids did a few decades ago, the study found. The ability to exercise vigorously for a prolonged period of time is a key measure of cardiovascular fitness, so this finding raises concerns about kids' fitness and physical health.

Even more serious are the implications for the health of the next generation of adults.

“If a young person is generally unfit now, then they are more likely to develop conditions like heart disease later in life,” said Grant Tomkinson, Ph.D., lead author of the study and senior lecturer in the University of South Australia‚Äôs School of Health Sciences in a statement.

It takes children today a minute and a half longer than their peers of 30 years ago to run a mile.

“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. The most important type of fitness for good health is cardiovascular fitness.”

The researchers looked at changes in running fitness between 1964 and 2010 among more than 25 million children ages 9 to 17 in 28 countries. Cardiovascular endurance was measured by the distance that the participants could walk or run or by how long it took to run a specific distance.

During the 46 years covered by the study, cardiovascular endurance among children and teens deteriorated. Although the degree of decline in activity varied somewhat from country to country, it was quite similar between boys and girls and younger and older children.

  • Cardiovascular endurance decreased by an average of 6 percent every decade between 1970 and 2000 among children in the U.S.
  • Children around the world are about 15% less cardiovascularly fit than their parents.
  • It takes children today a minute and a half longer than their peers of 30 years ago to run a mile.

Tomkinson notes that the decrease in fitness parallels the increase in overweight/obesity. Children's slower times running a mile may well reflect the extra weight they are carrying.

“About 30 percent to 60 percent of the declines in endurance running performance can be explained by increases in fat mass.”

Other contributing factors likely include excessive time spent in front of screens, lack of safe outdoor play spaces, decrease in physical education and recess time in school, more organized afterschool activities, and less free play.

Parents can give their children the gift of health now and into adulthood by limiting screen time and making activity part of their child's (and their own) day. Head to the playground; take kids on a hike or bike ride; walk to the store. Talk to teachers, principals, and policymakers regarding offering recess and gym classes.

It may be helpful to consult with your physician regarding age-appropriate exercise guidelines and investigate school and community resources for physical fitness activities, particularly if a child is overweight.