Stress affects us all in different ways. But, some of us are just a little more vulnerable to the nasty ways stress can mess with us. And, now, researchers at Concordia University have found that variations in heart rate may be a predictor of stress susceptibility.
In the study, published in this month's issue of the journal Stress, 76 undergraduate students first completed an online questionnaire to assess their levels of stress, anxiety, and depression during a low-stress period of the academic year. Then, in the lab, they had their baseline heart rate measured for seven minutes. Next, while their heart rate was still being monitored, participants were asked to worry about something in the future that could potentially have a negative influence on their life for five minutes. After this "free worry period," the participants were interviewed about their personal worries, and were asked to rate how likely and how awful each future consequence would be. Then, about three months later, right before finals week, the participants were given another mood questionnaire.
It turned out that the variation of participants' heart rates was correlated with their levels of psychological distress. Specifically, a lower resting rate during the low-stress time frame, combined with a higher level of reactivity in respiratory sinus arrhythmia (the way our heart rate naturally varies with our breathing patterns) in response to the worry conditions, was linked to more drastic changes in psychological distress during the high-stress time period. This means that those participants with lower variable heart rates (but also higher levels of change) had higher increases in anxiety ratings.
So, this suggests that health professionals might be able to use our heart rate variability (based on the interbeat interval, which is pretty easy to measure) to screen for people who are particularly susceptible to the negative effects of stress. It also suggests that heart rate might be a good target for those of us trying to relieve anxiety — which indicates that breathing techniques and focusing on the present rather than the future could be especially useful stress-relief tips. And, there's already technology on the way to help us out. But, even without the gadgets, finding your zen should be a definite priority.