The only way to get rid of temptation is to yield to it… I can resist everything but temptation. Oscar Wilde

Research has shown that our ability to resist impulse purchases goes down if we are exercising self-control in some other area, such as dieting.

But it isn’t just in shopping that we sometimes experience a moment of weakness or act contrary to our intentions. When our self-regulatory ability is being expended in one area, we can lose that ability in another. Dealing with stresses at work might leave you depleted and unable to resist that hot-fudge sundae.

Researchers have found a physical indicator of when people may be working hard at self-control and therefore, vulnerable in some other area by measuring heart rate variability (HRV).

HRV is higher when people are trying to resist temptation. The researchers noted that brain structures involved in self-regulation overlap with the structures that control HRV.

The article, Heart Rate Variability Reflects Self-Regulatory Strength, Effort, and Fatigue appears in the journal Psychological Science.