Increased sensitivity to heat pain in chronic low blood pressure

Abstract

While in elevated blood pressure reduced sensitivity to acute pain has been well established, little is known about possible alterations in pain perception within the lower range of blood pressure. In this study, sensitivity to heat pain was assessed in 40 subjects with chronic hypotension (mean blood pressure 96.5/57.7 mmHg) and 40 normotensive control persons (mean blood pressure 121.8/77.2 mmHg). Employing a contact thermode, heat stimuli were applied to the forearm. Pain threshold and tolerance were determined. Participants furthermore rated subjective intensities and unpleasantness of tonic heat stimuli (45.5-47.5 degrees C) on visual analogue scales and in a questionnaire. Possible confounding of sensitivity to heat pain with skin temperature, temperature sensitivity and mood was controlled for. In addition to blood pressure, functional features of the arterial baroreceptor system were related to pain experience. Therefore, estimates for the input on the baroreceptors, as well as baroreflex sensitivity were obtained. Hypotensive individuals exhibited markedly reduced pain threshold and pain tolerance, as well as increased sensory and affective pain experience. The measures related to the baroreceptor system were not associated with pain experience, suggesting that no significant modulation of heat pain occurs through this system. The results of this study complete the findings on hypertension-related hypoalgesia and suggest an inverse relationship between blood pressure and pain sensitivity across the whole blood pressure spectrum. Furthermore, increased proneness of hypotensive individuals to clinical pain may be discussed.

Aberrances in Autonomic Cardiovascular Regulation in Fibromyalgia Syndrome and Their Relevance for Clinical Pain Reports

“…Changes in states of the cardiovascular system modulate central nervous pain processing and subjective experience of pain, constituting an important source of antinociception (5). Experimental blood pressure elevation leads to considerable reduction in pain sensitivity (6), and tonic blood pressure is inversely related to pain experience (7)(8)(9). Epidemiologic studies furthermore suggested that high blood pressure levels may protect against chronic pain, for instance, headaches and musculoskeletal complaints (10,11).…”

Autonomic cardiovascular control and responses to experimental pain stimulation in fibromyalgia syndrome

“…Changes in states of the cardiovascular system modulate central nervous pain processing and subjective experience of pain, constituting an important source of anti-nociception [4]. Experimental blood pressure elevation leads to a reduction in pain sensitivity [5,6], and tonic blood pressure is inversely related to pain experience, e.g., [7][8][9]. A number of studies have furthermore indicated that high blood pressure may protect against clinical pain, for instance, headaches, musculoskeletal complaints, and post-surgical pain [10,11].…”

Cardiovascular-Emotional Dampening

“…For example, several studies have shown significant relationships between BP and affective responses to pain (7,10,11). Moreover, this association between BP and affect dampening has been seen in emotionally laden contexts unrelated to acute or chronic pain.…”