Slower dispositional respiration is associated with lower pain sensitivity, higher mindfulness and multiple unique neural mechanisms

The relationship between non-volitionally controlled breathing and pain remains unknown. The psychological mechanisms supporting this relationship are also poorly characterized. Anxiety and dispositional mindfulness, two antithetical constructs, are postulated to mediate the relationship between pain and respiration. Anxiety increases breathing and pain. In contrast, dispositional mindfulness is associated with lower anxiety and pain. Importantly, the neural correlates of respiration rate have not been identified. Seventy-four pain-free participants were administered the Five Faceted Mindfulness Questionnaire (FFMQ) and the Spielberger State Anxiety Inventory (SAI) before scanning. Two innocuous (35°C) and noxious (49°C; right calf) stimulation series during pseudo-continuous arterial spin labeling functional MRI and continuous respiratory were then acquired. Subjects were instructed to “remain still and close their eyes” and visual analogue scale (0 = “no pain” – 10 = “worst pain imaginable”) pain intensity ratings were collected after each series. Slower respiration was associated with lower pain intensity ratings during noxious (r = .26, p = .03) and innocuous (r = .28, p = .02) stimulation. Higher mindfulness scores were associated with slower respiration (r = -.28, p = .02) and lower pain (r = -.25, p = .03). State anxiety did not significantly co-vary with pain or respiration (ps > .18). When compared to 35°C, 49°C stimulation produced significant activation in the primary somatosensory cortex corresponding to the stimulation site, bilateral thalamus, secondary somatosensory cortex, anterior/posterior insula, and dorsal anterior cingulate cortex (dACC). Slower respiration was associated with greater activation in the subcallosal cortex, subgenual ACC, right-lateralized dorsolateral prefrontal cortex (dlPFC), putamen, anterior insula, and left caudate. Faster breathing was associated with greater activation in respiratory control centers within the pons, medulla, and cerebellum. These findings suggest that individuals who naturally breathe slower report lower pain and engage multiple unique executive-level processes supporting psychological resilience and self-regulation of affect. This work was supported by the National Center for Complementary and Integrative Health (R21-AT007247, F32-AT006949, K99/R00-AT008238, R01-AT009693; F32 AT010843) and the Mind and Life Institute's Francisco J. Varela Award.