Aerobic capacity lower in boys with hemophilia

NEW YORK (Reuters Health) - Boys with hemophilia have a lower aerobic capacity than their healthy peers, according to study findings published the Journal of Pediatrics. However, the overall muscle strength of these children is comparable to that seen in the normal population.

Aerobic capacity refers to the maximum amount of oxygen that the body can take in and use to generate energy --- the more oxygen used, the greater the physical performance. This also referred to as cardiovascular capacity - and cardiovascular fitness is associated with a lower risk of cardiovascular diseases, such as high blood pressure and coronary heart disease.

Hemophilia patients used to have a sedentary lifestyle, because of frequent episodes of internal bleeding into the muscles and joints, often leading to inflammation and joint diseases, note Dr. Tim Takken and colleagues from University Medical Center Utrecht, the Netherlands. Since clotting factor replacement therapy was introduced, hemophilia patients have fewer bleeding episode and are able to participate more in physical activities.

In this study, the researchers examined aerobic capacity in boys with hemophilia and if it correlated with aerobic capacity and muscle strength. A total of 47 boys, an average of 13 years old, were included in the study.

None of the participants experienced joint or muscle bleeds or other adverse events because of participation in the study and all of them were able to perform at maximal or near-maximal levels on exercise tests.

Compared with their healthy counterparts though, the peak oxygen capacity, heart rate, and work capacity were significantly lower among the boys with hemophilia.

However, total muscle strength was normal in the patients compared with the healthy controls, and almost no joint impairment or decrease in functional ability was found.

"The aerobic capacity of children with hemophilia is still lower than that of the normal population," Takken's team concludes. They also note that many of the boys with hemophilia were overweight, although they reported participating in a similar amount of physical activities.

SOURCE: Journal of Pediatrics, June 2008.