Experiencing positive affect and negative affect during stress: relationships to cardiac reactivity and to facial expressions.

We examined the relationship between experienced positive/negative affect and cardiac reactivity and facial muscle movements during laboratory tasks with different demands. Heart rate, respiratory sinus arrhythmia, pre-ejection period, and facial electromyography were measured during startle, mental arithmetic, reaction time task, and speech task. The results revealed that individuals experiencing high levels of positive affect exhibited more pronounced parasympathetic, heart rate, and orbicularis oculi reactivity than others. Individuals who experienced high levels of negative affects during the tasks showed higher corrugator supercilii responses. Men and women showed slightly different response patterns. To conclude, cardiac reactivity may be associated with positive involvement and enthusiasm in some situations and all reactivity should not automatically be considered as potentially pathological.