Editorial: Heart Rate as a Biomarker for Co-Occurring Externalizing and Internalizing Problems.

The article by Deutz et al.1 investigates associations between heart rate (HR) measures with child externalizing and internalizing psychopathology. HR relates to emotional arousal and reflects both sympathetic and parasympathetic nervous system activity. When measured at rest, HR relates to autonomic activity during a relaxing condition. HR reactivity (HRreactivity) is expressed as a change from resting or baseline that results after exposure to experimental stimuli.2,3 These stress-regulating mechanisms prepare the body for fight or flight responses, and as such can explain individual differences that might predispose to child psychopathology.