Effect of nutritional status on exercise performance in patients with chronic obstructive pulmonary disease.

The purpose of our study was to examine the nutritional status of patients with severe chronic obstructive pulmonary disease (COPD) (mean predicted FEV1, 30 +/- 11%) and to explore its relationship to functional capacity. Functional capacity was evaluated by measuring peak oxygen consumption (VO2max) using an incremental cycle ergometry test, a 6-min walk test, self-perceived level of dyspnea, and quality of life. The percentage ideal body weight (%IBW) was less than 90% in 33 of 135 subjects. Triceps skinfold thickness was less than 60% of normal in 19 of 33 of these subjects. Total lymphocyte count was not different between groups, whereas hemoglobin (14.9 versus 15.9 g/dl) and albumin (4.0 versus 4.1 g/dl) were marginally reduced in underweight subjects. Dyspnea and overall quality of life were unaffected by nutritional status. Maximal inspiratory (Pimax) and expiratory mouth pressures (PEmax) were weakly associated with %IBW (R2 = 0.04; p = 01 and R2 = 0.15; p less than 0.01, respectively). The %IBW was a predictor of VO2max (percent predicted) after controlling for FEV1 in regression analysis (partial R2 = 0.08; p less than 0.001). Despite the association of weight status with VO2max, the 6-min walk was not influenced by %IBW. The perceived intensity of exercise as judged by the Borg score was far greater with the bicycle exercise that with the 6-min walk (mean score, 10.6 +/- 1.2 versus 4.6 +/- 1.9). This was supported by the difference in heart rate after these two tests.(ABSTRACT TRUNCATED AT 250 WORDS)