Heart Rate Variability (HRV) is sometimes referred to as cardiac autonomic control or parasympathetic modulation.
Sounds pretty technical doesn’t it! Let’s look at it in layman’s (layperson’s) terms.
You probably know that the relaxation and contraction of the heart is known as heart rhythm. Rhythm is the response of the heart muscle to electrical signals coming from special cells and fibers in the upper and low chambers of the heart. The rate is usually somewhere between 60 and 100 beats per minute.
It wasn’t until fairly recently that doctors and researchers realized that there are slight differences in time between each beat (HRV). Put simply, HRV is the amount of time between each heartbeat. There is normally some variability in the time between the beats which can be the result of numerous different factors, but often vagus nerve activity.
You may wonder why you should care about HRV!
In essence, HRV is the balance between the parasympathetic (PNS) and sympathetic (SNS) nervous systems. Together they make up our autonomic nervous system (ANS). Here’s a brief description of what the ANS does: it regulates heart beat, heart rate, blood pressure, body temperature, digestion, breathing, and other basic life-sustaining functions of the body. The ANS is involved in all diseases. According to Dr. Bessel Van Der Kolk, author of The Body Keeps the Score, a poorly balanced autonomic system results in a variety of physical and/or psychological problems. Some of these physical illnesses include heart disease, cancer, fibromyalgia, migraines, and other forms of chronic pain.
Let’s look at the psychological effects of unbalanced SNS and PNS: When we inhale, we stimulate the SNS and our heart rate increases. When we exhale we stimulate the PNS, our heart rate decreases. When the SNS and PNS are balanced, our “arousal modulation” gives us control over our emotions and impulses, if and when, we encounter minor frustrations and disappointments. We can then calmly assess what is going on and choose how we want to respond. Those with a poorly balanced (or modulated) autonomic nervous system are easily thrown off balance both mentally (and physically) and are at high risk for psychological illness. Psychological illness can include depression, anxiety, mood swings, PTSD, and more.
The concept of measuring heart rate variability is now an accepted method to determine cardiac health and resilience in humans. HRV allows a doctor or researcher to measure the autonomic system (both PNS and SNS) velocity to detect and/or respond to unexpected stimuli. Yep! More technical jargon!
Measuring HRV helps show how the cardiovascular system adapts to changes caused by the environment. High HRV indicates a healthy adaptability and ability to function at a higher level and recover quickly from a stressful situation. Low HRV makes one less resilient and more susceptible to the consequences of stress as well as a wide range of disease. In times of stress, anger, depression, and so on, HRV is quite low. However, when you are calm and happy, your HRV is higher which translates to better cardiac health. As your mood improves, your cardiac health improves!
Here’s the bad news: HRV tends to decrease with age! Therefore, methods, particularly non-pharmacologic, to increase HRV are sought after and researched.
You might now wonder what this has to do with Tai Chi and/or Qigong!
Mindful awareness (as with mind/body exercises) encourages focusing on breath and relaxation and has a significant positive influence on HRV. Tai Chi, Qigong, and Yoga are good examples of mindfulness exercises which reduce stress and negative emotions. In this way, they help to improve the balance between the parasympathetic and sympathetic nervous systems.
There have been several studies done on the effects of Tai Chi and Qigong in HRV. A 2005 study published in the American Journal of Chinese medicine compared external Qigong with a placebo controlled group. The Qigong Qi therapy reduced the heart rate and increased the HRV greater than the control group. Researchers determined that external Qigong stabilized the sympathovagal function and cardiac autonomic nervous system. Qigong also stabilized the emotions of the participant.
A 2014 quasi-experimental study of middle and elderly people showed that after 12 weeks of Qigong, the experimental group exhibited significantly improved HRV, as well as peripheral vasomotor responses. The control group continued with their normal daily activities with little to no HRV improvement. A 2016 study compared HRV using Tai Chi versus arm ergometer cycling. The researchers concluded that Tai Chi, perhaps because of the mind component, could be more beneficial for older adults cardiac health. Both a 2016 systemic review of Tai Chi and it’s effects on HRV and a systemic review in 2017 of Qigong showed improved HRV.
Unfortunately, most of the studies were fairly small and often prospective. They also used different types of Tai Chi and Qigong, instrumentation, time intervals, and age groups. For scientific purposes, it is important to use the same parameters in order to confirm the benefits of Tai Chi and Qigong on HRV. Longer times of practice, equal time intervals, same martial art/Qigong form, larger sample size, and same measuring instrumentation are needed in order to provide a scientifically valid study. While more rigorous testing is needed regarding Tai Chi and Qigong’s impact on HRV, the evidence is strongly in favor of these mindfulness exercises ability to raise HRV.
Of course, we also need to recognize that there are other ways of increasing HRV: having a healthy diet, improved sleep, and positive lifestyle changes. Both the exercise component and controlled breathing of mindfulness exercises reduce stress which plays a major role in controlling HRV.
So now you have even more reasons to keep up your regular practice. If you aren’t currently practicing (or practicing intermittently), here is another reason to make it a priority! Your heart, body, and brain will all benefit!
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