The purposes of this study were to identify a zone of normality based upon ratings of perceived exertion (RPE) and compare the RPE of women with coronary artery disease to this zone. 45 healthy women (34.8 +/- 9.1 yr.) completed a Bruce treadmill test. RPE were estimated during the last minute of each workload. The zone of normality was established as the 95% confidence interval spanning the average line when RPE was regressed against MET. 51 women (66.6 +/- 9.3 yr.) with coronary artery disease completed a symptom-limited treadmill test. 31 of the women with coronary artery disease were taking beta blockers. RPE were compared to the RPE/MET relation of the zone. 57% of the women with coronary artery disease estimated RPE above the zone during the treadmill test. RPE responses above the zone of normality indicate an elevated perceptual strain for a given energy expenditure (i.e., MET). The zone of normality might be used as an aid in discriminating between normal and abnormal RPE responses during graded treadmill tests by women with coronary artery disease.