MONDAY, Aug. 10, 2015 (HealthDay News) -- When obese kids get moving, their cardiovascular health quickly improves even if they don't lose weight, a new review finds.
Australian researchers looked at six studies on the effects of exercise for obese children and teenagers. On average, the studies found no impact on kids' weight in the short term -- six to 12 weeks.
There was, however, a clear benefit seen when it came to kids' fitness levels and blood vessel function.
That's important because cardiovascular health in childhood often "tracks" into adulthood, said senior researcher Jeff Coombes, a professor in the School of Human Movement Studies at the University of Queensland, in Brisbane.
Past studies, he said, have shown that obese children often become obese adults, when they'll face heightened risks of type 2 diabetes and heart disease. But boosting kids' fitness levels and blood vessel function may trim those risks, Coombes noted.
Just as important, he added, those positive changes happen even if there's no obvious difference in the body's appearance.
"The findings from our analysis show improvements in cardiovascular health, independent of changes in body mass index or body weight," Coombes said.
Dr. Timothy Church, a professor of preventative medicine at Pennington Biomedical Research Center in Baton Rouge, La., said, "That's not surprising."
Weight loss is not necessary for exercise to benefit blood vessel function, said Church, who studies the health effects of improved fitness.
He said the new findings echo what's been seen in overweight adults: Exercise can make you fit even if you don't become skinny.
In the six trials in the review, which was published online Aug. 10 in Pediatrics, overweight and obese children were enrolled in various exercise programs. All involved exercise that gets the heart rate up -- such as walking, running, swimming, dancing and ball games -- and some added strength training into the mix.
The studies ran anywhere from six to 12 weeks.
Overall, Coombes' team found there was little change in kids' weight or body composition. But results showed an improvement in their fitness levels, and in endothelial function -- a measure of how well the blood vessels dilate and constrict in response to blood flow.
Problems with endothelial function can precede the development of artery-clogging plaques.
"I think that improvement in endothelial function is very important," Church said. "And I think this study is yet another example of how important exercise is."
Dr. William Muinos, who directs the weight management program at Nicklaus Children's Hospital in Miami, agreed.
In his practice, Muinos said, he routinely sees obese kids who already have high blood pressure. And exercise is an "important tool" in helping their blood vessels work better, he said.
So what's the best way for parents to get a sedentary child away from the TV or computer? By being active themselves, Muinos said.
"For at least one hour every day, do something fun with your kids," he advised. "Go for a walk, ride bikes. That 'family hour' is what works. It makes exercise a routine part of children's lives."
Church agreed. "I don't think we have a childhood obesity epidemic," he said. "I think we have a family obesity epidemic."
As important as exercise is, Muinos stressed, a healthy diet is essential, too. "Kids need plenty of fruits and vegetables, and a diet low in starchy foods and sugar," he said.
In the longer term, exercise and diet changes will probably trim obese kids' body fat, too, Coombes said. They may also put on some muscle -- so the number on the bathroom scale is not a great way to measure the benefits of exercise, he said.
The U.S. Centers for Disease Control and Prevention has advice on exercise for kids.