I have written earlier regarding the Heart Rate Variability, that is primarily caused by the Autonomous Nervous System (the opposite effects of PNS and SNS), and how a flexible HRV is related to better response to stress and reduced anxiety in face of external stressors. While looking at the evidence and linkages between HRV and emotional regulation, I had also speculated in it that a lower baseline or resting HRV may be reflective of depression and low regulation/motivation; while a high resting or baseline HRV reflective of Mania and high regulation/ motivation.
A recent study has looked into the issue of whether cognitive self -regulation (will power / motivation) is also associated with HRV. The study reported that higher baseline HRV was associated with more will-power and ability to resist temptation. Also, as they had surmised that will-power is a limited resource and hence the ability to resist temptation must exhaust the will- power ability, hence if the subjects showed higher HRV during the resisting temptation phase, then they would have exhausted their will-power reserves and would not persist in subsequent demanding tasks and this is exactly what they found.
The study consisted of measuring HRV, while the subjects were given a choice of eating cookies/candies or carrots. those who chose carrots over candies (thus exhibiting more will-power to resist the temptation of candies) also showed higher HRV.
In the second experiment, after the subjects chose candy or carrot , and hence supposedly exhausted their limited will-power cognitive reserves, they were asked to do a tough anagram exercise. Those who had chosen carrots were more likely to give up the task earlier. Yet those with higher baseline HRV showed high motivation and will -power regardless of whether they chose candies or not.
This I believe is a good corroborator of Higher resting HRV to be related to better self-regulation and mania , while lower baseline HRV to be related with depression and poor self-regulation. So maybe our hearts do tell us a lot about ourselves, our abilities to resist temptations and our will -powers.