More than 25 million kids, in 28 countries, tracked for nearly five decades, now comprise the American Heart Association’s (AHA) largest snapshot of global childhood fitness across two generations. The organization’s findings paint a grim picture for the kids of today, as they were found to be less fit than their parents were in measures of cardiovascular endurance.
Running has long been considered the gold-standard for measuring kids’ fitness levels. It’s simple, easy to measure, and almost totally inclusive — meaning that kids with poor upper body strength or low flexibility can perform equally well. The AHA’s analysis of 50 studies between 1964 and 2010 yielded substantial time differences among the two generations when it came to running one mile. Kids today ran, on average, 90 seconds slower than their parents’ generation did, proving empirically what many have known anecdotally for years: kids just aren’t playing as much anymore.
Lead author of the study and researcher at the University of South Australia’s School of Health Sciences, Dr. Grant Tomkinson said the risks associated with childhood obesity don’t stay within childhood. Kids who practice unhealthy lifestyle put themselves at greater risk for certain diseases as they enter adulthood. “If a young person is generally unfit now,” Tomkinson said in a press release, “then they are more likely to develop conditions like heart disease later in life.”
In the past 30 years, childhood obesity has more than doubled in children and tripled in adolescents, according to figures from the Centers for Disease Control and Prevention (CDC). In 2010, the last year the data was available, more than a third of children and adolescents were overweight or obese — obesity being defined as an excess of fat comparable to the child’s height, and overweight being defined as excess body weight due to fat, muscle, bone, water, or a combination of the four.
"It makes sense. We have kids that are less active than before," Dr. Stephen Daniels, a University of Colorado pediatrician and spokesman for the heart association, said during the AHA’s conference on Tuesday. "Kids aren't getting enough opportunities to build up that activity over the course of the day. Many schools, for economic reasons, don't have any physical education at all.”
There is no federal standard for physical education and health class requirements. The responsibility is left up to the states, which can decide independently whether to mandate that students complete a minimum amount of physical education per week, substitute a school sport for the requirement, or not establish any requirements at all. The U.S. Department of Health and Human Services currently recommends children do moderate- to vigorous-intensity physical activities that add up to 60 minutes over the course of the day.
“Young people can be fit in different ways,” Tomkinson said. “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, which is the ability to exercise vigorously for a long time, like running multiple laps around an oval track.”
Through the AHA analysis, Tomkinson and his colleagues found cardiovascular endurance declined similarly across boys and girls, children young and old, and among kids in various countries around the world, although each country varied independently. In the U.S., fitness declined by six percent per decade between 1970 and 2000. Overall, kids are roughly 15 percent less fit from a cardiovascular standpoint than their parents were.
These changes are motivated, the researchers speculate, by a mix of environmental, behavioral, and cultural factors, such as the advent of technology-based entertainment, declining physical education programs, and shrinking spaces where kids can play in public. Whereas kids used to flock to the streets and socialize in empty dirty lots, their imaginations are now activated through handheld devices and virtual realities.
The growing preference for sedentary lifestyles often results in the build-up of fat, which Tomkinson said correlates directly with diminished cardiovascular health — about 30 to 60 percent of the declines, he says. Outside the U.S., declines were less pronounced in countries such as Australia, New Zealand, and parts of Europe. Meanwhile, 20 million of the 25 million kids came from countries in Asia, where the declines remain just as persistent as in the U.S. The global slide into worsening health, Tomkinson said, should be added motivation for health care professionals and parents to push kids stateside to get up and move.
“We need to help to inspire children and youth to develop fitness habits that will keep them healthy now and into the future. They need to choose a range of physical activities they like or think they might like to try,” he said, “and they need to get moving.”