The Cardiac Orthostatic Stress Response as a Function of Internalizing Psychopathology and Sex in Typically Developing Youth-An Observational Study.

Stress-induced physiological changes offer insights into autonomic nervous system (ANS) function beyond resting cardiac activity, relevant to both physical and mental illnesses. Limited research exists on heart rate (HR) reactivity in children and adolescents, particularly in the context of internalizing psychopathology. In a study of n = 48 typically developing adolescents (mean age 16.31 years, SD = 0.51), HR and vagal-mediated heart rate variability (vmHRV) were assessed by electrocardiography during an orthostatic challenge, which served as a standardized physiological stressor. Regression models examined the association between HR metrics (baseline, reactivity, recovery) and self-reported internalizing psychopathology (depression and anxiety). Higher levels of internalizing psychopathology were negatively associated with vmHRV reactivity and recovery, and these associations were moderated by sex. Levels of anxiety and depression showed a stronger negative association with vmHRV reactivity in boys than girls, and anxiety levels showed a unique association with reduced vmHRV recovery in boys. These findings highlight sex-specific patterns in ANS functioning related to internalizing symptoms and stress-induced physiological responses in youth.