Influence of physical activity on cardiorespiratory fitness in children after renal transplantation

BACKGROUND: Cardiorespiratory fitness is significantly reduced in children with end-stage renal disease. The role of renal transplantation in improving cardiorespiratory fitness has not been thoroughly investigated. METHODS: In this work, we wanted to assess whether, in children after a successful renal transplant, the amount of weekly physical exercise affects cardiorespiratory fitness and left ventricular mass (LVM). The study was conducted on 16 children after renal transplantation and 36 matching healthy controls. Four groups were formed according to the weekly amount of physical exercise; all children received an echocardiogram and underwent a treadmill exercise test according to the Bruce protocol. RESULTS: Cardiorespiratory fitness is worst in renal transplant children with a weekly physical exercise <3 h; renal transplant children with a physical exercise of 3-5 h per week attain a cardiorespiratory fitness comparable to controls with a sedentary lifestyle (<3-h exercise per week); healthy controls with a weekly physical exercise of 3-5 h per week show the highest levels of cardiorespiratory fitness; the LVM assessed via echocardiography follows the same pattern. CONCLUSIONS: In children with a successful renal transplant, a weekly physical exercise of 3-5 h significantly improves the cardiorespiratory fitness and the LVM, up to the level of matching healthy controls with a sedentary lifestyle (<3 h exercise per week).