Inactivity endangers lives

2008-07-16 21:10

Lindsey Tanner

Chicago - One of the largest studies of its kind shows just how sluggish American children become once they hit their teens: while 90% of 9-year-olds get a couple of hours of exercise most days, fewer than 3% of 15-year-olds do.

What's more, the study suggests that fewer than a third of teens that age get even the minimum recommended by the government - an hour of moderate-to-vigorous exercise, like cycling, brisk walking, swimming or jogging.

The latest study, appearing in Wednesday's Journal of the American Medical Association, tracked about 1 000 US children at various ages, from 2000 until 2006.

Special gadgets were used to record their activity. Average levels of moderate-to-vigorous activity fell from three hours a day at age 9 to less than an hour at age 15.

The sharp drop raises concerns about inactivity continuing into adulthood, which could endanger kids' health throughout their lives, the study's authors said.

"People don't recognise this as the crisis that it is," said lead author Dr Philip Nader, a paediatrician and professor emeritus at the University of California at San Diego.

Inactivity is linked with greater risks for many health problems, including heart disease, obesity, high blood pressure and diabetes.

The new findings come just a week after an influential paediatricians group recommended that more children have their cholesterol checked and that some as young as 8 should be given cholesterol-lowering drugs.

James Griffin, science officer for the study, said that as children mature, "You would expect somewhat of a decline (in activity), but nothing of this magnitude."

He noted that the study coincided with the rise in popularity of video games, DVDs and Internet use - "all of the types of things that take children from outside and put them on a couch or in front of a computer".

Griffin said the results send a message to parents that it's important to teach their kids to balance computer time with more active pursuits, like walking the dog or shooting some hoops.

Dr Samuel Klein, director of Washington University School of Medicine's human nutrition centre in St. Louis, said the research provides a more powerful snapshot than previous studies.

The rapid drop-off in exercise by age 15 shows that the preceding years are "really an area we should target", said Klein, who was not involved in the study.

- AP