Six-minute walk by people with chronic renal failure. Assessment of effort by perceived exertion

The ability to exercise among 20 people with chronic renal failure was assessed on three tests by measuring the distance walked in 6 min, heart rate change from pre-exercise to postexercise and perceived exertion. Test 1 was conducted to minimize practice effects. Ten participants received exercise coaching for 3 mo between Tests 2 and 3, and 10 individuals were in a control group. Distance walked was highly correlated on the three tests; heart rate change and perceived exertion were only slightly less consistent. Three people changed their perceived exertion by more than one point between Tests 2 and 3, and these changes obscured differences between the exercise and control groups. Exclusion of data for those who changed by more than one point equalized perceived exertion changes in the two groups and revealed a significant (P < 0.05) increase in distance in the exercise group (+21.8 m) but not in the control group (+1.5 m). The study demonstrates that, although perceived exertion ratings are intended for use in incremental exercise testing, they are also valuable for assessing consistency v change in the effort of individual participants in single-intensity testing, such as a self-paced walk.