Published January 4 2015
Heart rate variability (HRV) is the variation in time interval between heartbeats, and is a measurement of autonomic nervous system function. A healthy heart is supposed to have a greater amount of variability in between the heart beats. Heart rate is regulated by the sympathetic and parasympathetic nervous systems, which are part of the autonomic nervous system. Having higher HRV is a sign of good adaptation and characterizes a person with efficient autonomic mechanisms, while having a lower HRV is usually an indicator of abnormal and insufficient adaptation of the autonomic nervous system (1) .
So why is it important to have a heart rate that is variable? Well, in the past it was thought that the heart was supposed to have a regular, steady rhythm. But even under resting conditions there is supposed to be some degree of heart rate variability. HRV can be an important indicator of health and fitness. As I mentioned in the opening paragraph, having low HRV usually means that there is an imbalance of the autonomic nervous system. And there is evidence that reduced HRV can increase the risk of developing certain health issues. One study showed that a reduced HRV can worsen the prognosis in people with certain health conditions such as a myocardial infarction, chronic heart failure, unstable angina, and diabetes mellitus (2) .
What Factors Influence Heart Rate Variability?
Numerous factors can influence HRV. Exercise, one’s breathing patterns, and even your feelings and emotions can influence HRV. Having a negative attitude and/or being stressed out on a regular basis will almost definitely lead to a decrease in HRV. On the other hand, having a positive attitude and doing a good job of managing your stress can lead to increased HRV.
A coherent heart rhythm pattern is when the sympathetic and parasympathetic nervous systems are in a state of synchronicity. The Institute of HeartMath  refers to this as psychophysiological coherence, and states that this is characterized by increased order and harmony in both our psychological and physiological processes. In other words, having an increase in heart rate variability will not only benefit us from a mental and emotional perspective, but from a physiological perspective as well.
What Does The Research Show?
There are a few research studies which show the benefits of increasing HRV. A randomized controlled clinical trial evaluated the impact of HRV on a population of 38 children with ADHD (3) . The participants demonstrated significant improvements in various aspects of cognitive functioning, and significant improvements in behavior were also found (3) . I also came across a case study from Santa Cruz County Children’s Mental Health Agency that reviewed the use of measurement of HRV to enhance the emotional regulation of patients (4) .
How Can You Increase Heart Rate Variability?
Although heart rate variability doesn’t directly relate to thyroid health, this doesn’t mean that increasing HRV can’t benefit those people with thyroid and autoimmune thyroid conditions. And so here are some of the things you can do to increase HRV:
Exercise. There is evidence that exercise can help to improve HRV (5)  (6) . One study evaluated HRV in 22 “exercise trained” and “exercise untrained” patients with myocardial infarctions (MI). The findings of the study suggested that those MI patients who exercised had autonomic pathways that were functionally better than MI patients who did not exercise (7) . Another study showed that following an eight-week cardiac rehabilitation program caused significant increases in HRV (8) .
Improve your stress handling skills. I’ve spoken about this numerous times in past articles and blog posts, as it’s important to block out time each day for stress handling. Some of the more common techniques that are utilized to help with stress management include meditation, deep breathing, and yoga, although there are other techniques. Spend at least ten minutes per day utilizing one of these techniques. And of course feel free to block out more than ten minutes if you’d like.
Check out HeartMath. I briefly mentioned the Institute of HeartMath  earlier, and I’ve mentioned HeartMath in other articles as well. I usually talk about this as a form of stress management, although it is different than most mind body medicine techniques in that it provides feedback. This is what I use on a daily basis to manage stress, as I have their EmWave2 and Inner Balance programs. Earlier I spoke about psychophysiological coherence, and this is what the EmWave2 and Inner Balance technologies measure and quantify. One thing to keep in mind is that coherence is not the same as relaxation. HeartMath does a pretty good job of explaining the difference between the two:
“At the physiological level, relaxation is characterized by an overall reduction in autonomic outflow (resulting in lower HRV) and a shift in ANS balance towards increased parasympathetic activity. Coherence is also associated with a relative increase in parasympathetic activity, thus encompassing a key element of the relaxation response, but is physiologically distinct from relaxation in that the system oscillates at its natural resonant frequency and there is increased harmony and synchronization in nervous system and heart–brain dynamics. Furthermore, unlike relaxation, the coherence state does not necessarily involve a lowering of heart rate, or a change in the amount of HRV, but rather is primarily marked by a change in the heart rhythm pattern.”
Keep a positive attitude. I know this can be challenging at times, especially for those who have a thyroid or autoimmune thyroid condition. But trying to have a positive attitude most of the time can not only help to improve HRV, but can also benefit your overall health as well. And so try your best to keep a positive attitude most of the time.
In summary, heart rate variability is the variation in time interval between heartbeats. One wants to have a high HRV in order to achieve optimal health, as having a low HRV can potentially lead to numerous health conditions. Some of the factors which influence HRV include exercise, one’s breathing patterns, and even your feelings and emotions. So in order to increase HRV you want to exercise regularly, do things to improve your stress handling skills, and try to have a positive attitude most of the time. And you might also want to check out the Institute of HeartMath .