Validity of the 6-minute walk test and step test for evaluation of cardio respiratory fitness in patients with type 2 diabetes mellitus.

Purpose: The purpose of this study was to evaluate the reliability, reproducibility, and validity of the 6-minute walk test and step test as substitutes for ergometer exercise in patients with type 2 diabetes mellitus.

Methods: The study included 54 women aged 50-70 years who had type 2 diabetes mellitus. All the patients performed a cycle ergometer-graded exercise test for cardiorespiratory fitness (V̇O2max), followed by 6-minute walk and step tests.

Results: The mean distance covered during the 6-minute walk test was 538 ± 54 m, and the mean recovery heart rate after the step test was 93 ± 11 beats/min. A significant correlation was found between the distances covered during the cardiorespiratory fitness test (V̇O2max) and those covered the 6-minute walk test (r = 0.542, p < 0.01) and step test (r = -0.490, p < 0.01) in the patients with type 2 diabetes mellitus. Regression equations for the prediction of V̇O2max were constructed from the distance covered, heart rate, age, weight, height, fasting blood glucose level, 2-hour postprandial glucose level, and glycated hemoglobin level during the 6-minute walk test and step test.

Conclusion: The 6-minute walk and step tests are simple to perform and reliable for the evaluation of cardiorespiratory fitness in patients with type 2 diabetes mellitus.