This study assessed self-selected exercise intensity of habitual walkers. Twenty-nine healthy adults (22 females, 7 males; age (mean +/- SD) = 34.9 +/- 8.6 yr) performed a typical exercise walk while walking speed was measured by an unseen observer. On a subsequent occasion, the subjects walked at the same pace on a treadmill while several variables related to exercise intensity were measured. The mean self-selected walking pace was 1.78 +/- 0.19 m.s-1. Mean percents of VO2max and HRmax elicited by the treadmill exercise were 52 +/- 11% and 70 +/- 9%, respectively. Mean MET level was 5.2 +/- 1.2, and ratings of perceived exertion (RPE) averaged 10.9 +/- 1.6. Based on reported frequency and duration of walking, weekly energy expenditure in exercise walking was estimated to be 1127 +/- 783 kcal.wk-1. These data suggest that the self-selected exercise intensity of healthy, habitual exercise walkers meets the American College Sports Medicine's recommendation for improvement of cardiorespiratory fitness. These data further suggest that, in this population, the average weekly energy expended through walking reaches a level associated with improvements in health and longevity.