Females display increased empathy for pain and poorer autonomic regulation under cognitive stress compared to males

Background: Empathy is a critical social process that involves both affective and cognitive components. Several studies have found that women have superior trait empathy compared with men, and there may be a biological basis for these differences. We investigated sex differences in empathy for pain and autonomic regulation (i.e., heart rate variability, HRV) in healthy young adults.
Method: Eighty participants (37 female, mean age 26.7) completed the Empathy for Pain scale, a paced breathing (PB) task where they were prompted to inhale and exhale at regular intervals (15 cycles per minute for two minutes), and the serial sevens (SS) task where participants counted backwards from 1000 by sevens while being pressured by the experimenter. The SS task induces mild cognitive and physiological stress. HRV was recorded from a 5-lead ECG system, and the log transformed square root of the mean squared differences of successive R-R intervals (lnRMSSD) was analysed, as an indicator of parasympathetic tone.
Results: Women reported higher empathic concern (p = .023) and affective distress (p = .005) than men when presented with a scenario whereby another person was in pain from an accidental injury. There were no sex differences in lnRMSSD during the PB or SS tasks taken alone; however, there was a significant sex difference in the relative change in lnRMSSD between tasks, whereby lnRMSSD increased in men for the SS task compared with the PB task, but it decreased between tasks from women (p = .01).
Conclusions: Females reported higher trait empathy for pain compared with men, and also displayed a relative decrease in parasympathetic regulation under mild cognitive stress compared with a state of rest. Taken together, these findings suggest that the increased empathic responses in females may be mechanistically associated with poorer emotional and physiological regulation.