Giving children more opportunities for physical education in school may not increase their overall activity level or be effective in reducing childhood obesity rates, a new study suggests.
According to researchers at the Peninsula Medical School in the United Kingdom, children will compensate for the amount of phys ed they get in school by increasing or decreasing the amount of exercise they get after school.
Researchers attached accelerometers -- devices that measure physical activity -- to children at three schools that offered varying opportunities for physical activity.
Students at the school with the most phys-ed time got an average of 9.2 hours of scheduled exercise a week; students
at the school offering the fewest opportunities got an average of 1.7 hours a week.
Even so, researchers found that students in all three schools were doing the same amount of physical activity throughout the week.
"The most surprising finding was that, given all this opportunity, at the end of the day, it made no difference. Children compensate for what they do or do not get," says Terry Wilkin, a professor of endocrinology and metabolism at the school and a lead author of the study.
"It's very counterintuitive. You ask Joe Public what controls physical activity, I'm quite sure he will tell you the environment and the opportunity," Wilkin says. "You measure it and you find something different."
Wilkin says he suspects the hypothalamus in the brain is what controls a child's level of physical activity, and he notes that it's regulated similarly to the temperature of a house.
"There's a set point, and when something tries to disturb that set point, the system registers the disturbance and rectifies this."
Russell Pate, chairman of the Department of Exercise Science at the University of South Carolina, says that while the findings do not prove conclusively that children compensate for the amount of physical education they receive, the study is "an interesting observation" worth more exploration.
"Before you draw a lot of firm conclusions, this sort of thing ought to be done in a larger number of schools and in schools where you can know a lot about the other influences on children's physical activity," Pate says.
Stephen Jefferies, president of the National Association for Sport and Physical Education, says that even if the brain controls activity levels as the study suggests, a lack of opportunity for exercise in schools could still be detrimental.
"I actually think the body does know (how much physical activity is necessary), but what we've created is an environment that precludes the body from doing what it needs to do," Jefferies says.
To see more of USAToday.com, or to subscribe, go to http://www.usatoday.com
Copyright 2009 USA TODAY, a division of Gannett Co. Inc.