Many studies demonstrate higher cardiovascular responses during exercise in subjects with peripheral arterial disease and intermittent claudication (PAD/IC) compared to subjects without PAD/IC. However, the relationship of these variables to exercise intensity is unreported. PURPOSE: To determine the relationships of heart rate (HR), systolic and diastolic pressures (SBP, DBP), and rate-pressure product (RPP) to estimated O2 uptake (EstVO2) during graded treadmill exercise testing in men with PAD/IC and to compare those responses to men without PAD/IC. METHODS: Subjects included 42 men with PAD/IC (mean age 69 yr, BMI 27.1 kg·m2, ankle/brachial index 0.60, B-blocker usage 60%) and 23 men without PAD/IC (mean age 68 yr, BMI 27.3 kg·m2, B-blocker usage 16%). All performed 2 trials of the Gardner treadmill protocol while HR, SBP, DBP and 0-4 pain ratings were monitored continuously with 12-lead ECG and manual sphygmomanometry at 2-min intervals. VO2 was estimated at each test stage based on subjects' body mass and treadmill speed and grade. Mann-Whitney U tests were used to compare regression components between groups. RESULTS: All cardiovascular responses were linearly related to EstVO2 between 0.5 and 2.0 L·min-1. Calf claudication pain ratings increased from 0 (none) to 4 (intolerable) during all treadmill tests in subjects with PAD/IC. Compared to subjects without PAD/IC, median linear regression slopes in subjects with PAD/IC were significantly higher for HR (40 vs. 24 b·min-1, P=.006), SBP (80 vs. 21 mmHg, P<.001), DBP (12 vs. -3 mmHg, P<.001), and RPP (162·10-2 vs. 56·10-2, P<.001). In subjects with PAD/IC, median Y-intercepts were significantly lower for SBP (97 vs. 114 mmHg, P=.001), DBP (66 vs. 74 mmHg, P=.009), and RPP (43·10-2 vs. 73·10-2, P=.001), and the median standard errors of estimate were significantly higher (P<.05) for SBP (472 vs. 283 mmHg, P=.018). CONCLUSION: Compared to men without PAD/IC, cardiovascular responses in men with PAD/IC increased at a faster rate and tended to be more variable during progressive treadmill testing. Differences between groups are likely attributable to claudication pain, multiple comorbidities, metabolic abnormalities, and physical inactivity common in PAD/IC subjects. Supported by VA Rehabilitation R&D Service grant A2860R.