Fewer than 1 in 3 American children get enough exercise every week. If they don’t get more active, more than 8 million will be obese by their 18th birthdays—and their health care and lost productivity as adults could cost the country close to $3 trillion, finds a new study in the journal Health Affairs.
“Physical activity is not something that’s nice to do, nice to have,” said Bruce Y. Lee, the executive director of the Global Obesity Prevention Center and an associate professor in international health at Johns Hopkins University, who led the study. “It’s an investment in encouraging kids to be healthy, and it also affects cognition and learning.”
Researchers at Johns Hopkins and the Pittsburgh Supercomputing Center at Carnegie Mellon University found fewer than 32 percent of children ages 8 to 11 get at least 25 minutes of strong physical activity at least three times a week. That’s actually a conservative recommended activity level by the Sports Association; the National Institutes of Health and the American Academy of Pediatrics call for at least an hour of moderate to vigorous exercise a day.
Many factors contribute to children becoming sedentary, Lee said: less time and budget in schools for physical education, recess, and after-school sports; less access to safe public parks and playgrounds, particularly for students in poverty; increasing specialization in youth sports that may increase cost and barriers to entry; and rising screentime for children.
“Kids are getting on average nine hours of screen time a day. When you are sitting there watching your television or smartphone for nine hours a day, something else has got to give,” Lee said. “As a culture, we are spending less time on the sidewalk and on the street.”
Costs of Sedentary Kids
Using a computer simulation of all children in that age group nationwide, the researchers found that increasing the percentage of children who exercise regularly to 50 percent would cut the adult obesity rate and save nearly $22 billion in medical costs and lost productivity over their lifetimes. Getting at least 3 out of 4 kids active would save more than $40 billion.
The simulation used Census and other large data sets to create individual child avatars based on federal data on height, weight, age, and home location, and a starting body-mass index. The program generated the children’s daily nutrition and calorie intake based on federal data on American children’s eating habits, and then calculated changes in their weight over time, based on different levels of physical activity. As the simulated-children aged, the program also calculated their adult risk of being overweight, and the associated medical issues, such as diabetes, cancer, and heart disease, throughout their virtual lives.
In one 2013 analysis, the National Institute of Medicine found changes in school policies could add significantly to the amount of physical activity young adolescents get each day, as the chart at right shows.
“One of the challenges in education is there’s been a focus on individual things—get test scores up, get this specific indicator up—but the whole purpose of education is to build a child up so that they can function better throughout their entire lives,” Lee said. “These things have to be looked at as a system, and part of that system is the body.”
A version of this news article first appeared in the Inside School Research blog.