Prednisone's Effect on Exercise Capacity in the Kidney Transplant Recipient

A 2003 study published in Kidney International, the official journal of the International Society of Nephrology, concludes that prednisone may contribute to lower spontaneous improvements in exercise capacity, possibly by limiting increases in muscle strength. The researchers further conclude that the low exercise capacity found in all transplant recipients, whether taking prednisone or not, at one year post-transplant suggests a need for patient exercise training to optimize physical functioning.

The basis for the study was that although exercise capacity increases significantly after transplantation, over time it does not further improve and patients remain low compared to normal levels. Suspicious that prednisone may be to blame in the debilitating process, the researchers studied cardiorespiratory fitness, muscle strength, and body composition in two groups of transplant patients - one group in which prednisone was included in the immunosuppression therapy and one group in which it was not. Testing was performed at 3 and 12 months post-transplant, and the 12 month data was compared to 15 normal sedentary controls.

The results showed the non-prednisone group had greater gains in cardiorespiratory fitness and muscle strength. In fact, the study said there were significant gains in cardiorespiratory fitness and muscle strength in those patients not taking prednisone. Patients taking prednisone showed actual deterioration. However, researchers cautioned that all patients remained low in peak oxygen uptake compared to the sedentary normal controls. The sedentary normal controls achieved 96% (+/-18%) of their age-predicted maximal capacity, compared to only 67% in the patients at 1 year post-transplant.

Heart rates in both study groups at 1 year post-transplant were significantly lower than the sedentary controls. Patients' maximal heart rates registered only 75% - 85% of age predicted maximal heart rates, while the controls (who took no meds that affected heart rates) came in at 98%. Further, the Respiratory Exchange Ratio, which is a physiologic indicator of maximal effort, was significantly lower in all patients at 1 year compared to the controls, suggesting, the authors say, a muscle metabolic limitation to higher levels of exercise among the patients.

The researchers determined that prednisone is not the cause for increased body fat following transplant, as both groups had a greater fat mass than the controls at 1 year, even when controlling for gender differences between the groups. Finally, the patients not on prednisone had significantly larger muscle fiber size (type IIX, for those of you scoring at home) than those taking prednisone.

So there you have it - further evidence of how truly important aerobic and strength exercise is for our continued good health, especially for those of us taking prednisone. For more details on the study and its results, please click here.