Overweight children with asthma report more exercise limitations than normal-weight kids with asthma, even though their asthma is not necessarily more severe, according to the results of a small study.

Heavier children with asthma also tend to be on more medication, despite the fact that “on paper” their symptoms are no worse than those of average-weight kids, researchers report.

The study of 64 asthmatic children ages 8 to 12 found that objective measures of lung function were no worse in overweight and obese kids and that these children were not less fit than their average-weight peers.

Yet heavier children were more likely to say they had a hard time engaging in their favorite activities, and were prescribed more medication, according to findings published in the March issue of the journal Pediatrics.

It’s possible that because of the demands of a greater body mass, overweight children have more breathlessness during exercise than normal-weight kids do, according to the study’s lead author, Dr. Paul T. Pianosi of Dalhousie University in Halifax, Nova Scotia, Canada.

This may seem intuitive, he told Reuters Health, but it has never been shown in research.

If heavier children have a greater perceived effort and breathlessness during activity, this could lead to their being prescribed more drugs even if their asthma is not particularly severe, Pianosi and his colleague Heather S. Davis note in their report.

They contend that doctors should keep an “open mind” and try to figure out what’s at the root of a child’s exercise limitations before prescribing more asthma medication.

The researchers point out that, in the case of oral steroids, which may be used for severe asthma, treatment can actually spur weight gain. The potential for treatment to add to the risk of obesity in some cases highlights the importance of thoroughly testing lung function in children with asthma symptoms, they conclude.

In other findings, Pianosi’s team saw no relationship between asthma severity and physical fitness among children of any weight. Instead, children who were more confident in their athletic prowess showed greater fitness in exercise tests.

Pianosi pointed out that when children’s asthma is properly controlled, they should be able to do all the things their non-asthmatic friends do.

“There are professional and Olympic athletes who are living proof,” he said.

SOURCE: Pediatrics, March 2004.