Dyspnea and a limitation in exercise performance are important cause of disability in patients with chronic obstructive pulmonary disease (COPD). A depleted nutritional state is a common problem in pati ents with a severe degree of chronic airflow limitation. This study was carried out to assess the factors determining the maximum exercise capacity in patients with COPD.

The resting pulmonary function, nutritional status, and maximum exercise performance was assessed in 83 stable patients with moderate to severe COPD. The nutritional status was evaluated by bioelectrical impedance analysis. Maximum exercise performance was evaluated by maximum oxygen uptake(VO₂max).

Among the 83 patients, 59% were characterized by nutritional depletion. In the delpleted group, a significantly lower peak expiratory flow rate(p<0.05), Kco(p<0.01) and maximum inspiratory pressure(p<0.05), but a significantly higher airway resistance(p<0.05) was observed. The maximum oxygen uptake and the peak oxygen pulse were lower in the depleted group. The VO₂max correlated with some of the measures of the body composition : fat-free mass (FFM), fat mass (FM), body mass index(BMI), intracellular water index (ICW index), and pulmonary function: forced vital capacity(FVC), forced inspiratory vital capacity(FIVC), diffusion capacity(DLCO) : or maximum respiratory pressure: maximum inspiratory pressure(PImax), maximum expiratory pressure(PEmax). Stepwise regression analysis demonstrated that the FFM, DLCO and FIVC accounted for 68.8% of the variation in the VO₂max.

The depletion of the FFM is significant factor for predicting the maximum exercise performance in patients with moderated to severe COPD.