Cardiovascular activity and chronic pain severity

OBJECTIVE: Objective markers of chronic pain severity are needed when examining and treating patients with chronic pain whose suffering may be overstated or underestimated. This study tested a hypothesis that the strength of cardiovascular (CV) reactivity in response to a social evaluative threat and orthostatic challenge is a reliable index of severity of pain-related complaints. METHODS: Measurement of CV reactivity and response styles in 34 men and 16 women with chronic pain from different bodily injuries, were retrieved from a larger database of patients. Measurement of CV reactivity in response to a postural challenge was repeated twice (sessions 1 and 2) on the same day of a medical examination which includes a psychosocial evaluation . RESULTS: A decrease in systolic blood pressure (SBP) from session 1 to session 2 was found in subjects with low pain severity scores, but not in those with high pain severity scores. High scores for pain catastrophizing/ magnification and pain-related emotional distress were independently associated respectively with a SBP increase at an early-point in time and a SBP decrease at a mid-point in time after standing up from lying down. Stronger heart rate reactivity responses to orthostatic challenge indicated greater protection against the presence of these chronic pain symptoms. CONCLUSIONS: This biobehavioral protocol enables measurement of chronic pain suffering and protection in three dimensions: physical, emotional, and cognitive.