Peak oxygen uptake estimation from a moderate 500-m treadmill walk in older women with cardiovascular disease

Background and objective Low levels of cardiorespiratory fitness are associated with a high risk of cardiovascular disease (CVD) and all-cause mortality in women. The aim of this study was to determine the validity of a 500-m moderate treadmill-walking test for estimating peak oxygen uptake (VO2peak) in older women with CVD. Methods Fifty-three women with stable CVD (age 70.4 ± 8.2 years) underwent exercise testing during an outpatient cardiac rehabilitation/secondary prevention program. Each patient completed a maximal cardiopulmonary exercise test, and a moderate and self-paced (11–13/20 on the Borg scale) 500-m treadmill-walking test. Treadmill walk time, age, weight, height, and heart rate during the test were entered into prediction equations previously validated for VO2peak estimation in male patients. Results Measured and estimated VO2peak values were not different (20.8 ± 4.3 vs 21.3 ± 4.6 mL/kg/min, P = 0.12). The comparison between measured and estimated VO2peak values yielded a correlation of R = 0.92 (SEE = 1.3 mL/kg/min, P < 0.0001), with the slope and the intercept that coincided with the line of identity (Passing and Bablok analysis, P = 0.65). Residuals were normally distributed with a mean value of − 0.5 mL/kg/min. Examination of the Bland–Altman analysis does not show systematic or proportional error. Conclusion A moderate and self-regulated 500-m treadmill-walking test is a valid tool for VO2peak estimation in older women with CVD. These findings may have practical implications in the context of transitioning from clinically based programs to fitness facilities or self-guided exercise programs in older women with stable cardiovascular disease.