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.
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.
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.
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.
aAutonomic and Neuroendocrinological Laboratory Dresden, Department of Neurology, University Hospital Carl Gustav Carus, Dresden University of Technology, Dresden, Germany
bDepartment of Epidemiology and Public Health, University College London, London, UK
cDepartment of Neurovascular Hypertension and Kidney Disease, Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia
dHypertension in Africa Research Team (HART), School for Physiology, Nutrition and Consumer Sciences, North-West University, Potchefstroom, South Africa
Correspondence to Dr Manja Reimann, Autonomic and Neuroendocrinological Laboratory Dresden, Department of Neurology, University Hospital Carl Gustav Carus, Dresden University of Technology, Fetscherstr. 74, 01307 Dresden, Germany. Tel: +49 351 458 3862; fax: +49 351 458 5873; e-mail: firstname.lastname@example.org
Abbreviations: ANCOVA, analysis of covariance; BP, blood pressure; BSA, body surface area; CPT, cold pressor test; CRP, C-reactive protein; CSI, coping strategy indicator; GHQ, General Health Questionnaire; MET, metabolic equivalent; γGT, γ-glutamyl transferase
Received 8 February, 2012
Revised 20 June, 2012
Accepted 6 August, 2012