Fat-free mass depletion is associated with poor exercise capacity irrespective of dynamic hyperinflation in COPD patients

Abstract

BACKGROUND: In patients with COPD, we investigated the effect of the fat-free mass (FFM) on maximal exercise capacity and the relationship with changes in operational lung volumes during exercise. METHODS: In a cross-sectional study 57 patients (16 females; age 65 ± 8 y) wereconsecutively assessed by resting lung function, symptom-limited cardiopulmonary exercise test, and body composition by means of bioelectrical impedance analysis to measure the FFM index (FFMI; in kilograms per square meter). RESULTS: Patients were categorized as depleted (n = 14) or nondepleted (n = 43) according to FFMI. No significant difference in gender, age, and resting lung function was found between depleted and nondepleted patients. When compared with non-depleted COPD patients, the depleted COPD patients had a significantly lower O2 uptake at the peak of exercise and at anaerobic threshold as well as at peak oxygen pulse, oxygen uptake efficiency slope (OUES), and heart rate recovery (HRR) (P