Nonlinear associations between cardiovascular stress reactivity and emotional reactivity and emotion regulation among adolescents.

Cardiovascular stress reactivity (CVR) is considered as a physiological pathway linking emotional reactivity and emotion regulation with psychopathology. However, the associations between CVR and emotional reactivity and emotion regulation remain underexplored, with limited evidence showing that either excessive or blunted CVR is associated with emotional reactivity and emotional regulation. Recently, moderate CVR has been theoretically hypothesized to be related to optimal outcomes; however, whether CVR is nonlinearly associated with emotional reactivity and emotion regulation still needs to be investigated. Parents of 341 junior school students reported their children's emotional reactivity and emotion regulation on the Emotion Questionnaire, and the students were invited to participate in a mental arithmetic task with continuous cardiovascular monitoring indexed by heart rate (HR) and systolic and diastolic blood pressure (SBP, DBP). Results did not reveal any linear relationships between CVR and emotional reactivity or emotion regulation. However, quadratic associations between HR, SBP reactivity and emotional reactivity and emotion regulation were found even after controlling for sex, age and BMI. Specifically, there was a U-shaped association between HR, SBP reactivity, and emotional reactivity, while there was an inverted U-shaped association between HR, SBP reactivity, and emotion regulation. These findings suggest that moderate to high rather than exaggerated or blunted CVR reflects adaptive emotional reactivity and better emotion regulation among adolescents.