1 Department of Psychology, Concordia University, Montreal, Canada.
2 Department of Health, Kinesiology and Applied Physiology, Concordia University, Montreal, Canada.

Brooding rumination is an intrapersonal emotion regulation strategy associated with negative interpersonal consequences. Resting respiratory sinus arrhythmia (RSA), a psychophysiological marker of self-regulatory capacity, may buffer the association between maladaptive emotion regulation and negative interpersonal behaviors. The current work examines the moderating effect of RSA on the association between brooding rumination and different negative interpersonal consequences. Across three convenience samples, individuals with lower RSA showed a stronger association between brooding rumination and more negative interpersonal behaviors as well as less perception of received instrumental social support (Study 1; n = 154), higher levels of interviewer-rated interpersonal stress (Study 2; n = 42) and a stronger indirect association between brooding rumination and depressive symptoms via daily interpersonal stress (Study 3; n = 222). These findings highlight the negative interpersonal consequences of brooding rumination, particularly among individuals with lower RSA.