Outdoor Reproducibility of a 1-km Treadmill Walking Test to Predict Peak Oxygen Uptake in Cardiac Patients.

Introduction: The aim of this study was to determine whether the 1-km treadmill walking test, previously developed to predict peak oxygen uptake ((Equation is included in full-text article.)O2peak) in stable cardiac outpatients, could be reproduced outdoors.

Methods: Fifty male cardiac outpatients performed the 1-km walking test on a treadmill and on a flat track within 1 week. (Equation is included in full-text article.)O2peak was estimated for both testing conditions considering age, height, weight, walking speed, and heart rate.

Results: Average walking speed was slightly higher during outdoor conditions (5.73 ± 0.77 km/h vs 5.55 ± 0.84 km/h), whereas mean heart rates were similar for both testing conditions (102 ± 18 beats/min vs 103 ± 16 beats/min). (Equation is included in full-text article.)O2peak values for treadmill and outdoor tests were not significantly different (26.4 ± 4.1 mL/kg/min vs 26.8 ± 4.5 mL/kg/min) and were strongly correlated (r = 0.93, P < .0001). The slope and the intercept of the (Equation is included in full-text article.)O2peak values were not different from the line of identity.

Conclusions: This moderate and perceptually regulated 1-km walking test administered outdoors gives similar results compared with a similar test performed on a treadmill. Therefore, (Equation is included in full-text article.)O2peak can be reasonably estimated using both testing modalities. This suggests that the outdoor 1-km test can be applied for indirect estimations of cardiorespiratory fitness in an outpatient setting.