Validation of the Borg scale in participants with type 2 diabetes mellitus Background: Borg Rating of Perceived Exertion Scale (RPE) is a psychophysiological measurements that translates physical stimuli to a psychological construct, which is perceived exertion.Its use is simple and it represents the effort perception.Each number of the scale is associated with a heart rate or percentage of maximal oxygen consumption (VO 2 max), which estimates the intensity of exercise.Aim: To validate RPE scale in patients with type 2 diabetes mellitus (DM2).Material and Methods: Thirty five DM2 participants with a median age of 59 years underwent an incremental exercise test in a treadmill with breath-by-breath analysis of oxygen consumption.After every three minute stage, the RPE scale was applied and correlated with oxygen consumption variables.Results: There was correlation coefficient of 0.91 between RPE score and VO 2 max.A RPE score of 11 corresponded to 52% of VO 2 max, a RPE score of 13 corresponded to 76% of VO 2 max, a RPE of 15 corresponded to 88% of VO 2 max and a RPE of 17 correspondent to a 100% of VO 2 max.Conclusions: RPE Scale is valid in patients with type 2 diabetes as an estimate of the intensity of physical activity.