Physical activity counteracts increased whole-body protein breakdown in chronic obstructive pulmonary disease patients

Chronic obstructive pulmonary disease (COPD) is associated with increased whole body protein breakdown and low-grade systemic inflammation. We aimed to determine if physical training of patients with COPD induces anti-inflammatory effects and decreases whole-body protein breakdown. Nineteen subjects with severe (FEV₁=31±1) COPD were randomized into a training group (n=9) and a control group (n=10). Twenty healthy subjects were studied for baseline comparison. The "COPD training" group participated in an outpatient rehabilitation program consisting of endurance training (walking at 85% of VO_2max) twice weekly for 7 weeks plus daily home-based training. Maximum walking distance increased by almost 70% in the training group after 7 weeks of training. At baseline, the concentrations of C-reactive protein (CRP) and IL-18 in plasma were increased in subjects with COPD compared with healthy subjects (P<0.05) and leucine rate of appearance (R_a) was ∼15% greater (P<0.05) in subjects with COPD. Training had no effect on the plasma concentration of inflammatory markers but decreased leucine R _a in subjects with COPD by ∼10% (P<0.05). In conclusion, 7 weeks of physical training markedly improved endurance in patients with COPD and accelerated whole-body protein breakdown in patients with COPD was attenuated by physical training independent of changes in inflammatory markers.