Heart rate variability (HRV) is an indicator of autonomic nervous system regulation and has been linked to executive function (EF), with higher resting HRV linked to stronger executive function performance. Findings regarding HRV during task performance (task HRV) and HRV reactivity (task HRV minus resting HRV) in relation to EF performance have mixed results. This study aims to identify distinct HRV-EF subgroups in a sample of adult mothers. 

Participants were a sample of 120 adult mothers, with a mean age of 32 years old. Resting HRV (eyes open/closed baseline), task HRV (Stroop, WCST, Tower of Hanoi), HRV reactivity and EF performance were standardized and entered into a k-means cluster analysis. EF was assessed using Stroop mixed condition, WCST perseverative errors (reverse-scored) and Tower of Hanoi completion time (reverse-scored), then combined into a composite EF score. 

The cluster analysis identified three distinct HRV-EF clusters: Cluster 1 exhibited large HRV reactivity during tasks but the lowest EF performance, Cluster 2 showed higher resting HRV and the strongest EF performance, Cluster 3 demonstrated consistently low HRV with moderate EF performance. There were more evident differences across clusters for resting HRV and EF performance, while age related differences were minimal. 

These findings suggest that resting HRV may be more strongly associated with executive function than task related HRV increases. Identifying HRV-EF subgroups may address mixed findings regarding task HRV and HRV reactivity, and contribute to additional understanding of individual differences in autonomic regulation and executive function.