DALLAS — Today’s kids can’t keep up with their parents. An analysis of studies on millions of children around the world finds they don’t run as fast or as far as their parents did when they were young.
On average, it takes children 90 seconds longer to run a mile than their counterparts did 30 years ago. Heart-related fitness has declined 5 percent per decade since 1975 for children ages 9 to 17.
The American Heart Association, whose conference featured the research Tuesday, says it’s the first to show that children’s fitness has declined worldwide over the last three decades.
‘‘It makes sense. We have kids that are less active than before,’’ said Dr. Stephen Daniels, a University of Colorado pediatrician and spokesman for the heart association.
Health specialists recommend that children 6 and older get 60 minutes of moderately vigorous activity accumulated over a day. Only one-third of American kids do now.
‘‘Kids aren’t getting enough opportunities to build up that activity over the course of the day,’’ Daniels said.
The new study was led by Grant Tomkinson, an exercise physiologist at the University of South Australia. Researchers analyzed 50 studies on running fitness — a key measure of cardiovascular health and endurance — involving 25 million children ages 9 to 17 in 28 countries from 1964 to 2010.
The studies measured how far children could run in 5 to 15 minutes and how quickly they ran a certain distance, ranging from a half-mile to 2 miles. Today’s kids are about 15 percent less fit than their parents were, researchers concluded.
The decline in fitness seems to be leveling off in Europe, Australia, and New Zealand, and perhaps in the last few years in North America. However, it continues to fall in China, and Japan never had much falloff — fitness has remained fairly consistent there.