Momentary Associations of Autonomic Nervous System Activity Measured via Heart Rate Variability with Affective and Arousal States

Affective and biophysiological states are inherently linked, which is partly due to the activity of the autonomic nervous system. Heart rate variability is a commonly used indicator of autonomic nervous system activity. The present study examines the associations between heartrate variability indicators with perceived arousal and affective states using two 14-day experience sampling studies combined with ambulatory assessment of physical activity and heart rate variability. A total of 197 individuals (72.1% female) aged 18 to 29 years provided 11,269 measurements with complete surveys and corresponding valid accelerometry and electrocardiography data. In particular, we investigated heart rate and the root mean square of successive differences (RMSSD) as indicators for cardiac activity. We found a positive within-person association between heart rate with positive affect and perceived energetic arousal, while the association was negative for RMSSD. The opposite pattern was found for negative affect. No associations of heart rate or RMSSD with perceived tense arousal or generally on the between-person level were found. Mediation analyses revealed that the associations between heart rate variability and affect were partly mediated by perceived energetic arousal. The results of this study suggest that intraindividual fluctuations in heart rate variability indicators are associated with fluctuations in energetic arousal and affect. This study suggests a primarily state-dependent nature of the relationship between the autonomic nervous system activity and affect and highlights perceived energetic arousal as a potential mediator between them.