Respiratory Sinus Arrhythmia: a Marker of Resilience to Pain Induction

Background There may be significant individual differences in physiological regulatory responses to the experience of pain and stress. Respiratory sinus arrhythmia is a physiological indicator that may have implications for efficient physiological responses to pain and stress. Purpose Fatigue is an indicator of inefficient self-regulation under stressful conditions. The current study examined processes that impact changes in fatigue in response to pain. Methods Fifty-nine women (33 with fibromyalgia and 26 healthy controls) were exposed to repeated thermal pain stimuli and were asked to rate their feelings of fatigue after each block of thermal pain exposures. Results Self-reported fatigue affect increased during pain induction, but greater respiratory sinus arrhythmia predicted less-pronounced increases in fatigue affect across induction trials. Conclusions Respiratory sinus arrhythmia appears to be a promising indicator of physiological resilience to pain, predicting an attenuated effect of repeated pain exposure on self-reported fatigue. Implications of efficient regulation of pain, fatigue, and long-term physical health are discussed.