Interoception, blood pressure, and pain: unraveling their interaction under stressful and resting conditions.

Elevated blood pressure is commonly linked to diminished pain perception, a phenomenon known as blood pressure-related hypoalgesia. Interoception, the ability to perceive and interpret internal bodily signals, has been previously linked to both blood pressure and pain perception, although findings in the literature remain mixed. We investigated the relationship between blood pressure, pain perception, and interoception under both non-stressful (Pilot Study) and stressful (Main Study) conditions. In the Pilot Study, resting measures of blood pressure, pain thresholds and interoception were assessed in 26 healthy participants. Regression analysis revealed that higher systolic blood pressure was associated with increased pain thresholds, in line with previous findings. In the Main Study, the same variables were assessed in 46 healthy participants at rest and when a stress condition was induced by a validated virtual reality stress paradigm (i.e. the IMVEST). The effectiveness of the stress induction was confirmed through physiological measures (heart rate, heart rate variability, cortisol) and psychological assessments (perceived stress). No significant changes in blood pressure or pain threshold were observed following stress exposure. However, moderation analyses revealed that systolic blood pressure moderated the relationship between interoceptive beliefs (measured via the MAIA questionnaire) and pain perception: a positive association between the tendency to notice internal bodily sensations and pain threshold emerged only in individuals with high systolic blood pressure. This relationship was not observed in individuals with average or low systolic blood pressure. Taken together, these findings suggest that individual differences in cardiovascular physiology and interoceptive processes may shape pain perception.