Carotid artery massage was carried out in a cross-section of 95 healthy elderly subjects (51 men and 44 women, mean age of 74 years) to assess the heart rate response and associated symptoms. These subjects were drawn from a larger group of randomly selected healthy elderly people living in Southampton. They had no history of myocardial infarction or stroke and were not taking any drugs that might enhance the carotid sinus reflex. A continuous distribution of response to carotid artery massage was seen with a median percent change in RR interval of 11.6% (IQR 22.9%); 66% had a percent change in RR interval of < 20%, 90% had a change of < 50%, and 9.5% a change of > 100%. Carotid sinus hypersensitivity (sinus arrest > 3 s) was found in 4 previously asymptomatic subjects; a prevalence of 4.2% (95% CI 1.2%-10.4%), and this was associated with dizziness in 2 of these 4 subjects. Dizziness also occurred in one other subject who had a change in RR interval of 178%. The definition of an abnormal carotid sinus reflex is arbitrary given the continuous RR interval response to carotid artery massage. In diagnosing carotid sinus syndrome, the RR interval response to carotid artery massage alone is not sufficient, as this maneuver must also reproduce the patient's presenting symptoms.