Psychological status is related to six minute walk test performance in patients with obstructive lung disease

Purpose: The purpose of this study was to investigate the relationship of psychologic status (PS) to distance ambulated during the six minute walk test (6′WT). Methods: PS was measured with the SF-36 Health Status Profile (SF-36) and the 6′WT was administered without encouragement using the methods of Guyatt in 34 subjects (mean±SD, age=60±8 yrs; 15 males, 19 females) with obstructive lung disease (FEV₁=25±8%; FVC=51±17%). Results: Significant correlations were found between the 6′WT and several domains of the SF-36, with PS identified as the greatest univariate (r=0.44, r²=0.19, p=0.009) and multivariate predictor (coefficient=3.19, p=0.005; model r²=0.37) of distance ambulated during the 6′WT. Conclusions: PS is significantly related to exercise performance in patients with obstructive lung disease. Thirty-seven percent of the variability of the 6′WT could be accounted for with a multivariate model of PS. The 6′WT is a functional performance measure which is dependent upon PS. Clinical Implications: Measurement of PS may provide a better understanding of exercise performance in patients with obstructive lung disease.