Interoceptive awareness and resting heart rate variability in women

Purpose: To test the hypothesis that greater resting heart rate variability (HRV) is associated with better interoceptive awareness in women. Methods: Thirty four women participated in the study (mean age = 22.76, SD = 3.77). From a five-minute recording of resting heart rate, several time and frequency-domain measures of HRV were calculated: high-frequency HRV (HF), low-frequency HRV (LF), standard deviation of NN intervals (SDNN), root mean square of differences between adjacent NNs (RMSSD), number of pairs of successive NNs differing more than 50 ms (NN50), percentage of NN50 (pNN50), and standard deviation of heart rate (STD HR). Interoceptive awareness was assessed through a heartbeat perception task. Results: Interoception correlated directly with almost all time-domain measures of HRV: SDNN (r = .41, p = .017), RMSSD (r = .39, p = .025), NN50 (r = .34, p = .046), pNN50 (r = .40, p = .021). Interoception did not correlate with STD HR (r = .18, p = .29) nor with the frequency-domain measures: HF (r = .30, p = .09), LF (r = .28, p = .11). Conclusions: The results support the view that resting HRV (an index of emotion regulation, associated with physical and mental health) tends to be greater among women with more accurate awareness of bodily responses.