Determinants of achievement in stair climbing as an exercise test

Physicians routinely discuss pulmonary function and its impact on prognosis or operative risk. Although many studies have related various measures of pulmonary function to postoperative outcome, there has been no study designed to determine which of the spirometric measures of pulmonary function tests reflects the actual abstract idea of pure pulmonary function. A homogeneous population of 70 male patients was subjected to pulmonary function tests and a simple stair climb. Measures of pulmonary function (including FEV1, FEV1%, FVC, FVC%, and MVV%) were factor analyzed in a measurement model of pulmonary function to obtain reliability and validity estimates in predicting performance on a simple stair-climb test. The analysis revealed several interesting aspects concerning the relative importance of the various spirometric measures of pulmonary function tests. The validity estimates of the pulmonary function measures were as follows: FEV1% = 0.917; FEV1 = 0.886; MVV% = 0.769; FVC% = 0.715; FVC = 0.694. Analysis indicates that the FEV1% was the single best spirometric indicator of pulmonary function when predicting the physiologic outcome (followed closely by the FEV1). In addition, the various spirometric measures of pulmonary function were not equally valid nor interchangeable in such analysis. Although the number of stairs climbed correlates well with pulmonary function (r = 0.626), the coefficient of non-determination (i.e., 1-r2) suggests that about 61% of the performance on the stair climb may be explained by other parameters (i.e., cardiac function, determination, altitude, etc.).