The relationship between risk for hypertension and the regulation of blood pressure and pain sensitivity /

High blood pressure is associated with decreased sensitivity to pain in humans and animals. Interestingly, hypoalgesia has also been observed in normotensive organisms at risk for hypertension, suggesting that it may be related to processes involved in the development of hypertension rather than with elevations of blood pressure per se. Sensitivity to laboratory and naturalistic daily aches and pains was assessed in young normotensive women and men with or without a parental history of hypertension and varying degrees of resting blood pressure. In women, risk for hypertension, as defined by a parental history of hypertension, relatively elevated systolic blood pressure, or a combination of the two, was associated with decreased pain reports and increased pain threshold for mechanical finger pressure, but not for the cold pressor test. Offspring of hypertensives also exhibited a reduced response to the pain stimuli compared to offspring of normotensives as assessed by the objective physiological measure of respiratory sinus arrhythmia (RSA). Group differences observed in the laboratory were generally maintained in reports of daily pain, with significant correlations emerging between laboratory and naturalistic pain reports. To assess the role of cardiopulmonary baroreceptor stimulation in blood pressure-related hypoalgesia, young men varying in risk for hypertension were exposed to finger pressure during a period of passive leg elevation and two control periods. Men with relatively elevated systolic blood pressure exhibited reduced pain during the period of leg elevation but not while in a supine position, nor following the valsalva manoeuver. The results of these studies support an association between risk for hypertension and pain sensitivity. This relation appears to extend to naturalistic pain encountered in daily life. Further, there is promising evidence suggesting that this relationship is influenced by cardiopulmonary baroreceptor activity