Sedentary summer undoes school-year fitness gains

By Anne Harding

NEW YORK (Reuters Health) - A lazy summer vacation can wipe out all the benefits of school-based fitness programs for obese adolescents, a new study shows.

While obese middle school students boosted their cardiovascular fitness and pared down their body fat percentage after 9 months of lifestyle-focused fitness classes, these gains had been lost when the school year rolled around again, Dr. Aaron L. Carrel of the University of Wisconsin Children's Hospital in Madison and colleagues found.

Similarly, the subjects' fasting insulin dropped during the school year, signaling a reduced risk of type 2 diabetes and other chronic illnesses, these levels bounced back by the end of the summer.

"We in some ways lost all the benefits that the school year had promoted the previous year," Carrel told Reuters Health in an interview. His team was surprised and disappointed by the findings. "Most of us had sort of assumed that summertime would mean less sitting in classrooms and more physical activity."

Carrel and his team had previously reported on the benefits of the special physical education classes, which lasted 45 minutes and were held five times over the course of 2 weeks. The researchers followed up with 17 of the program participants at the beginning of the subsequent school year.

It's possible that the findings only hold true for obese children and that normal-weight kids are more active during their summer breaks, Carrel said. Nevertheless, he added, "we worry that this might be evidence that larger groups of kids also may not be as active as we believe."

For fitness programs to have a sustained benefit, they must be offered year-round, the researchers conclude.

"Maybe parents need to be a little bit more cognizant of trying to promote daily activity for our kids," Carrel added. One possibility, he suggested, would be for parents to let kids earn time on the computer or watching TV by spending some active time outside.

SOURCE: Archives of Pediatrics and Adolescent Medicine, June 2007.