Psychophysiological response to acute stress and interoceptive patterns in Borderline Hypertension: Insights for clinical relevance

Hypertension is a key cardiovascular risk factor associated with altered pain perception and interoceptive processes. Experimental evidence suggests that elevated blood pressure may reduce pain perception, a phenomenon known as blood pressure-related hypoalgesia. Since pain and interoception share common neural pathways, and stress affects both systems, their interaction may contribute to dysregulated psychophysiological states. This study explored the relationships among blood pressure, pain perception, and interoception, under stressful and non-stressful conditions in individuals with and without borderline hypertension (BH). The final aim was to identify early psychophysiological markers of cardiovascular risk. Sixty participants (30 BH, 30 age-matched normotensive controls HS) completed a three-session experimental protocol: baseline, stress induction, and recovery. Across sessions, measures of heart rate (HR), heart rate variability (HRV), blood pressure, salivary cortisol, pain threshold, interoceptive accuracy (Heartbeat Counting Task), interoceptive sensibility (MAIA-2), and perceived stress (visuo-analogue scales, VAS) were collected. Stress was induced using a validated virtual reality protocol called IMVEST. IMVEST successfully led to increased blood pressure in both groups, with BH individuals generally showing higher values. HRV decreased during stress and returned to baseline only in HS, indicating reduced autonomic flexibility in BH participants. Both groups reported higher levels of perceived stress and salivary cortisol during the stress induction. BH individuals showed higher interoceptive sensitivity, though interoceptive accuracy did not differ between groups. Moderation analyses revealed that interoceptive sensibility, but not accuracy, was negatively associated with pain threshold during stress in BH individuals. Specifically, higher awareness of internal bodily signals (MAIA-Noticing) was associated with a lower pain threshold. These findings highlight distinct physiological stress responses in BH individuals, particularly reduced autonomic flexibility and altered interoceptive sensibility. Such patterns may represent early indicators of cardiovascular dysregulation and offer potential targets for future treatments.