Heart rate, determined by palpation of the carotid, radial, or temporal artery, is commonly used to monitor exercise intensity. It is known that massage of the carotid artery has a baroreceptor reflex effect on the heart rate. The heart rate, monitored with and without carotid palpation, at rest, during exercise, and immediately post-exercise was determined in 60 male cardiac patients (39-65 years of age) following either myocardial infarction (n=52), bypass surgery (n=6), or those with angina pectoris (n=2). The mean changes in heart rate with carotid palpation in the testing group were -3.5 bpm at rest and -2.2 bpm during exercise; in the training group the changes were +0.8 bpm at rest -3.1 bpm post exercise. While the mean decrease at rest in the testing group was statistically significant, each of the decreases in resting, during, and post-exercise heart rates were too small to be accurately monitored by palpation over a 10- or 15-sec count, a usual procedure in exercise rehabilitation programs. Provided the patients are correctly instructed and technique regularly checked, there appears to be no reason why carotid palpation should not be used in cardiac exercise rehabilitation programs to determine resting, exercise, or post-exercise heart rates.