Guest post by Gina Cairney
Twenty minutes of physical activity per day over three months can reduce the risk of obesity in children, according to a study by the Journal of the American Medical Association, and can also reduce total body fat.
Of course, 40 minutes of physical activity per day over three months is even better for children, the study also found, reducing more total body fat and the risk of developing obesity-related diseases like Type 2 diabetes and plaque buildup in the arteries.
"If exercise is good for you, then more exercise ought to be better for you and that is what we found for most of our outcomes," Dr. Catherine Davis, clinical health psychologist at the Institute of Public and Preventative Health at Georgia Health Sciences University said in a press release.
Previous studies found that exercise reduces metabolic risk factors, like diabetes, in children, according to the study, but evidence of the relationship between the amount of exercise, or "dose-response," and metabolic risk in children is not available. This study looked to test just that: The dose-response and its effect on insulin resistance (a risk factor for diabetes), total and visceral body fat, and aerobic fitness in children.
Some 220 obese or overweight children, ages 7 to 11, were recruited during 2003-2006 from 15 elementary schools in Richmond and Columbia counties in Georgia, and Aiken county in South Carolina, for a trial of aerobic exercise and health.
The young participants were split into six groups of about 30 to 40 children each, and randomly assigned to a low-dose treatment of 20 minutes of aerobic exercise per day, a high-dose treatment of 40 minutes per day, or the no-treatment control group with no aerobic activity. Aerobic exercises included running games and modified sports games that kept the children moving throughout the duration of the exercises.
Davis and her colleagues found that daily and total energy expenditure were higher in the 40 minute exercise group compared to the 20 minute exercise and control groups. Children who were in the low-dose exercise group showed an 18 percent reduction in insulin resistance, and the high-dose exercise group had a 22 percent reduction, compared to the control group with no aerobic activity.
"It's practical in the sense that we were able to quantify the dose required to make these changes," Davis said in the statement. "If you are able to get kids active for 20 minutes every day in school, whether through physical education or taking a running break during lunch, that can make a real difference."
But as more schools divert time away from recess and physical education to keep up with instruction time and test preparation, will the United States be able to make significant strides in preventing overweight, obesity, and obesity-related diseases in children and adults? Is the United States slated to become the couch-potatoest nation in the world?!
If we continue at the rate we're going now, then yes, the U.S. just might become a massive couch potato. As previous posts on this blog mentioned, about a quarter of Americans 6 years and older are considered totally inactive, and 13 states could have adult obesity rates higher than 60 percent by 2030!
So what will it take to get America back into shape? More inspiring, adult role models, or laws that look to improve physical education in schools, or something else?
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