(336) Gender Differences in Cardiovascular Reactivity to Experimental Pain Assessment in Pain-Free Adults

Abstract

There is a broad literature indicating gender differences in cardiovascular heart diseases. However, gender differences in cardiovascular reactivity to experimental pain have revealed conflicting results. Therefore, we aimed to establish gender differences to experimental pain assessment in cardiovascular reactivity. Cardiovascular reactivity was measured by the change in Central Blood Pressure (CBP), Peripheral Arterial Stiffness (PAS), and Heart Rate Variability (HRV) before and after experimental pain assessment in 28 healthy subjects (12 males, age = 43.7046±6 years; 16 females, age= 49.31±7). CBP and PAS were determined non-invasively by pulse wave analysis (XCEL, SyphgmoCor). High-frequency (HF) and low-frequency (LF) bands were explored as a HRV parameter during each of the phases as an index of vagal cardiac control and sympathetic cardiac activation (MP-150, Biopac). Thermal stimuli were applied to the forearm by a contact thermode to assess thermal pain Tolerance. Repeated measures ANOVA showed a significant interaction term between gender and central diastolic blood pressure [F(1,25)=4.66, p=0.04], where males experienced a significantly steeper increase than females (males ΔCBP 11.35 mm Hg vs. females ΔCBP 2.21 mm Hg) . The Central Augmented pressure and the AIX@HR75 (PAS indicators) increased significantly between baseline and pain tolerance with a significant main effect of gender, where females had a higher central augmented pressure and AIX@HR75 than males. No interaction term was observed between HRV variables and gender. These preliminary results imply that in general males have a higher cardiovascular reactivity due to pain induction than females. However, females showed larger PAS, which could produce a ceiling effect on their cardiovascular reactivity. Further studies in a larger sample and in patients with chronic pain could provide stronger evidence about the relationship between chronic pain and cardiovascular risk.