Reference equations for the six-minute walk in healthy adults

In order to establish reference equations for prediction of the total distance walked during six minutes (6MWD) for healthy adults, we administered the standardized 6-min walk test to 117 healthy men and 173 healthy women, aged 40 to 80 yr. Oxygen saturation (Sa_O2), pulse rate, and the degree of dyspnea (Borg scale) were determined before and at the end of the walk. The median distance walked was 576 m for men and 494 m for women. The 6MWD was significantly less for men and women who were older and heavier, and for shorter men. The resulting gender-specific regression equations explained about 40% of the variance in the distance walked for healthy adults: for men, 6MWD = (7.57 × height_cm) - (5.02 × age) - (1.76 × weight_kg) - 309 m, and for women, 6MWD = (2.11 × height_cm) - (2.29 × weight_kg) - (5.78 × age) + 667 m. These reference equations may be used to compute the percent predicted 6MWD for individual adult patients performing the test for the first time, when using the standardized protocol.