Greater cardiovascular reactivity to a cold stimulus is due to higher cold pain perception in black Africans: the sympathetic activity and ambulatory blood pressure in Africans (SABPA) study

Abstract

Objective: To evaluate the role of pain perception and pain stimulus components for blood pressure responses to stress in the black and the white African population with hypertension. Basic methods: Cardiovascular regulation in response to a cold pressor stimulus was studied in hypertensive black (n = 110) and white (n = 95) Africans. Perception of stressfulness of the task was assessed on a seven-point Likert scale. Chronic stress levels were evaluated by the General Health Questionnaire and the Coping Strategy Indicator was used to assess individual coping behavior. Autonomic and baroreflex function was evaluated by spectral analysis. Main results: The cold pressor test elicited significant blood pressure elevations with higher relative increases in the black Africans. The higher blood pressure reactivity in black Africans was accompanied by a substantially greater cardiac response and lower parasympathetic outflow as compared with white Africans. Black Africans also reported higher chronic stress levels and rated the stimulus as more painful than their white counterparts. A significant interaction was observed for cardiovascular responses with pain perception but not with chronic stress. Individuals with high pain perception exhibited less dampening of autonomic cardiac exertion than those with low or moderate pain perception. Principal conclusion: Black Africans display a more pronounced cold pressor test-induced rise in heart rate and blood pressure, which may be explained by greater pain-related increments in blood pressure. A higher cognitive appraisal of pain and a blunted baroreflex-mediated dampening of autonomic structures may contribute to the exaggerated blood pressure reactivity in black Africans.