THE INFLUENCE OF RESTING BLOOD-PRESSURE AND GENDER ON PAIN RESPONSES

Recent research suggests that resting blood pressure is inversely rela ted to pain sensitivity, even among normotensives; however, most of th ese studies have included only male participants. To determine whether this hypoalgesic effect of blood pressure was also present in females , we investigated thermal and ischemic pain responses in a group of ag e-matched, normotensive females and males as a function of resting blo od pressure. Thermal pain threshold and tolerance were determined, and a cross-modality thermal magnitude matching procedure was conducted, after which ischemic pain threshold and tolerance were determined usin g the submaximal effort tourniquet procedure. Systolic pressure, diast olic pressure, and heart rate were obtained using an automated blood p ressure monitor with a pneumatic cuff positioned around the left ankle . Females provided higher normalized thermal magnitude estimates and a shorter time to ischemic pain tolerance, but no gender differences em erged on other pain measures. Systolic, diastolic, and mean arterial p ressures were significantly correlated with thermal and ischemic pain responses among males but not females, with higher blood pressure bein g associated with lower pain sensitivity. After adjusting for resting blood pressure, the gender difference in normalized magnitude estimate s was only marginally significant, and the gender difference in ischem ic pain tolerance became nonsignificant. These findings are consistent with previous research indicating an inverse relationship between blo od pressure and pain sensitivity. Additionally, the findings also sugg est that blood pressure may partially moderate gender differences in p ain sensitivity, Potential mechanisms and clinical implications of the current findings are discussed.