Heart rate variability as a marker of self-regulation

Objective: Problems of self-regulation play a key role in many of the most important individual and societal problems today. The ability to delay gratification and override impulses allows one to stay focused on long-term goals and sacrifice immediate pleasure for more rewarding future outcomes. The present study was undertaken to determine whether earlier findings regarding the relationship between self-regulation and heart rate variability (HRV) could be replicated and extended. We predicted that participants with a higher baseline HRV would have a longer persistence time on difficult and unsolvable anagram tasks. We also predicted that under conditions requiring greater self-control, HRV would increase. Method: Sixty participants (16 men and 44 women) were recruited from a local university and local community and were compensated ten dollars for participation. Data were obtained for each participant in 60-minute sessions using electrophysiological measurements. The study consisted of an experimental paradigm designed to parallel previous research on self-regulation. Two groups of participants were given the same set of difficult and unsolvable anagrams. The difference between these two groups was that before encountering the anagrams, one group was asked to try not think of a white bear (suppression), while the other group was asked to try to think of a white bear as much as possible (expression). This white bear experimental manipulation followed by anagram tasks has been used as a way to induce self-regulatory fatigue. Results: Baseline HRV predicted persistence on the unsolvable anagram. Overall, increases in HRV were observed over time within the suppression and expression groups. We were unable to replicate findings that participants in the high self-regulatory effort condition, which in our case was the suppression group, had a larger increase in HRV. However, we were able to replicate findings that participants in the expression condition persisted longer on the anagram task compared to participants in the suppression group but only when accounting for physical activity scores. Lastly, our manipulation check revealed that participants in the two conditions did not differ in how difficult they found the manipulation of self-regulatory exertion. Conclusion: The present study serves as a means of advancing our knowledge of the relationship between HRV and self-regulation so that we can more successfully treat medical and psychiatric populations with seriously impaired self-control. Further research is needed to clarify the relationship between self-regulation and HRV and will need to include a larger sample size, a more diverse population, and a broader scope of methods to challenge self-regulation.