Understanding Heart Rate Variability: The Key to Monitoring Your Stress Levels

I’m certain we have all heard of “resting Heart Rate” and “max Heart Rate,” but what about Heart Rate Variability (HRV)? It sounds like it is something we do not want; I mean who wants their hear rate to be variable? Most would think a constant and steady beat is desirable, well, that couldn’t be further from the truth, let me attempt to explain…..

I need to preface this by saying this may be a longer blog than usual because it requires some detail and some big words; I will try to simplify so it is understood. But please, if the content gets to heavy or complicated, read to the end, that is where I discuss the practical implications for each of us, what is most important to you and what is most important to me, how to help you take advantage of this and be healthier.

What is HRV?

HRV is a great indicator of the state level of stress you body is in during a given period of time.

A low HRV score means you are under more stress and a high HRV score means you are under less stress.

Let’s assume a healthy heart beats at 60bpm (endurance athletes generally have a lower heart rate in beats per minute). But we cannot assume it beats at 1 beat per second; for some it may, however for others it will not. For some it may beat at 0.85s and then again at 1.35s; others may be 0.99s and 1.01s, consistently, but which is more desirable? I can confirm it is better to be more “variable” than constant, in terms of getting indications of our stress and readiness levels. This is “Healthy Irregularity.”

Now that we can understand what HRV is, let us look at why it happens and then what it means.

Why does it occur?

Ok, here is where it can be a bit complicated, the HRV has everything to do with our nervous system, specifically, the Autonomic Nervous System (ANS). This is the nervous system that we cannot consciously control, think about stressful sweating, blood flow, digestion and….heart rate! These are all changing and adapting without us being aware of it.

The ANS is now further divided into two more components 1) The Parasympathetic Nervous System (PNS) – REST & DIGEST and 2) The Sympathetic Nervous System (SNS) – FIGHT OR FLIGHT

Let’s give you a practical example so its easier to understand…..

Let’s say you are sitting now reading this blog and are relaxed in bed….you’re mostly in a Parasympathetic state, calm, resting and relaxed, not sweating or overtly stressed. But lets say as you are reading this blog and your home fire alarm starts to sound, you will most likely jump and react, your heart rate will increase, you may sweat, you will worry about your family and belongings and the chemicals of stress will be released and you will move from an Parasympathetic to Sympathetic State.

Another term called Intrinsic Heart Rate is a term that is used when our heart beats without influence of either PNS or SNS, this heart rate is determined to be 100bpm….this is individual but it allows for a simplified way to measure HRV. The PNS lowers the heart rate away from 100 and can cause immediate changes or variability in the beats because it only affects a few beats at a time, not every beat below 100, it then allows it to rise closer to 100bpm again. Whereas, the SNS raises it above 100bpm but is in control of every heart beat the entire time it is over 100bpm, this allows less variability to occur.

Therefore, when we are under more PNS control and in a relaxed state of being and less stressed, we will have more HRV. Whereas, when we are stressed and under higher SNS control, there is much less HRV. This is why a greater HRV is desired not a lower HRV.

Why does it matter?

HRV matters for many different reasons. For the elite athlete it can measure whether or not you rested and recovered from the previous training sessions and let you know how hard you should or should not push your next workout. This is a great way to avoid overtraining and physical breakdown and injury.

But what about for the rest of us that are not athletes? HRV is directly related to sleep, digestion and ability to tolerate and handle our daily routines.

By improving our HRV, we tune into the PNS and become healthier, and more capable to tolerate the environment around us. This is important for all of us as humans.

Quick self test of HRV

If you want to do a quick test on yourself to become aware of HRV, take a finger and find your pulse at your wrist or neck. When you breath in you activate your Sympathetic Nervous System and your pulse intervals will become shorter. Now exhale, you’re activating your Parasympathetic Nervous System and your pulse intervals will become longer.

Also, it is important to note that HRV can be influenced by intense exercise, becoming sick, alcohol consumption, smoking, dehydration and poor dietary choices.

How can I measure HRV?

The most accurate way to measure HRV is with an Electrocardiogram (ECG), but since most of us do not have one of these, this is not practical. But in the ever evolving world of technology and wearables, many of the watches, Apple, Samsung and Garmin, utilize software to measure HRV, however it is best measured at rest when we are sleeping, so it you do not wear your watch to sleep you will not get a measurement that is truly accurate. There is also a ring made by OURA. You can wear it easily at night and the app tracks your sleeping patterns as well, and even better, you can turn off all Bluetooth and NFC communication at night while you sleep and the ring still reads your biometrics; then connect in the morning to see your results.

If you have any questions or comments, I’m happy to talk with you, I love integrating health and technology and there is no denying the science, HRV matters!

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Frequently Asked Questions

Why calculate HRV vs resting heart rate (RHR)?

For years trained athletes and competitors used RHR to determine whether they were adequately rested and ready to train vs overtrained and I need of more rest….this proved to be subjective and much too influenced by factors that could throw off norms, but most importantly it was not sensitive enough for accurate data. As we came to be aware of HRV and what it means to the Autonomic nervous system, specifically, the parasympathetic nervous system, it became a better measure of our state of health and readiness. It was an indicator of being ill, overtrained, dehydrated, eating too late, drinking too much, eating too late, too little sleep, etc. When the parasympathetic nervous system was optimal, HRV increased and once norms were established, a readiness value can be created and populations can predict when they are in optimal health. For this reason, HRV is much better to use than RHR to establish an optimal state of being health.

How can we influence our HRV to increase?

This is the question we all want to know. To put it simply, this can be influenced through many factors, but they are still individualized for each person. However, we influence our HRV, by influencing out Parasympathetic nervous system! We want to create an optimal state of “rest and digest”. It is well known that this can be established through, meditation, cold exposure, proper nutrition, avoid alcohol and smoking, eat at least 3 hours prior to bed, avoid illness, avoid excessive exercise, slow peaceful walks, and deep breathing or mindful breathing techniques. These can all be used to establish a better performing PNS and thus a better HRV.

How can you measure HRV?

HRV is measured, by many of the daily wearable we use in todays world, Specific wearables that pride themselves on accurate HRV measurement are 1) Oura ring 2) Whoop band 3) Apple Watch 4) Fit bit 5) Biostrap 6) Apollo neuroscience

These are all excellent ways to measure HRV….we can choose who is best for us depending on what we find easiest or integrated with our prior devices.

About Ernie Bagnulo

Dr. Ernie Bagnulo is a chiropractor and clinic owner of WIN Health Clinics. He studied at New York Chiropractic College and graduated Magna Cum Laude. He completed his Medical Acupuncture training at McMaster University and is now a senior instructor in the program.

Medical Disclaimer:

The information presented in this blog post is for educational purposes and should not be interpreted as medical advice. If you are seeking medical advice, treatment or a diagnosis, consult with a medical professional such as one suggested on this website. The Clinic Accelerator Inc. and the author of this page are not liable for the associated risks of using or acting upon the information contained in this article.

Understanding Heart Rate Variability: The Key to Monitoring Your Stress Levels