Effects of exercise training on protein kinetics in children with cystic fibrosis

Exercise training in children with cystic fibrosis (CF) could be benificial in sustaining maximal oxygen consumption (VO2max), but may have detrimental effects on nutritional status. We studied 12 clinically declined CF patients during 6 months (pre-training) and subsequently during 6 months bicycle ergometry at home. VO2max, body weight and fat free mass were measured every 6 months. Fasting leucine kinetics was studied at 3 and 9 months. Leucine oxidation (OX) and turnover (Q) were calculated at plateau from enrichments of 13CO2 in breath air and 13C-leucine in plasma, respectively; non-oxidative leucine disposal (NOLD) was calculated as Q minus OX.