Effect of physical training on fat-free mass in patients with chronic obstructive pulmonary disease (COPD)

Abstract

Background. Weight loss and depletion of fat-free mass are common problems in patients with chronic obstructive pulmonary disease (COPD) and are related to muscular weakness and exercise intolerance. Physical training of COPD patients has good effect on exercise tolerance and quality of life. The aim of this study was to examine factors that affect change in fat-free mass after physical training, in patients with COPD.

Patients. Patients were examined before and after a 4-month exercise period. Weight and height were measured, and bioelectrical impedance was performed. Fat-free mass (FFM) was calculated, by a three-compartment model, and fat-free mass index (FFM_I) was calculated as FFM kg/m² and body mass index (BMI) as kg/m2. A symptom-limited ramp ergometer test and 12-minute walk test (12MWT) were performed. Dyspnoea score of daily activities was determined by Chronic Respiratory Disease Questionnaire (CRDQ). Blood was taken for analyses of C-reactive protein (CRP) and fibrinogen. Patients with a BMI <21 kg/m² were given nutritional support during the training period.

Results. A total of 27 patients completed the training (64 years, FEV1 31% of predicted). Patients with low FFMI gained 1.2 kg, whereas those with normal FFMI lost 0.7 kg (p = 0.04). In multivariate analyses high age (p = 0.03), low FEV1 (p = 0.02), and a high level of dyspnoea (p = 0.01) at baseline were found to be negative predictors for increase in FFM.

Conclusions. Difficulties in increasing the fat-free mass in COPD patients by physical training seem to be associated with dyspnoea in daily life and impaired lung function (FEV₁).