How To Talk To Your Heart - Heart Rate Variability (HRV) And Your Health
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How To Talk To Your Heart - Heart Rate Variability (HRV) And Your Health
IF Insider No. 59
Our last issue (IF Insider No. 58) featured an article by our distinguished guest, Sarb Johal, a psychologist, author, broadcaster, and the founder of Noise Reduction, also hosted on Substack. We were delighted to have Sarb write for the IF Insider and if you have not yet checked out his thought-provoking article TRF Is My Frenemy, then we encourage you to do so!
For our premium subscribers, in this week’s Research Spotlight, we will look at the often-stated claim that exercise somehow strengthens your immunity. Is this claim backed up by the research?
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How To Talk To Your Heart - Heart Rate Variability And Your Health
Before we get into what heart rate variability means and why you should care, to really understand this concept you need to know a little bit about the heart itself, your heart, and the way your heart’s electrical activity is measured on the EKG.
You have very likely had an EKG or ECG as it is also known, done as part of a medical checkup at some point, which is simply a graphical recording of the electrical activity of the heart. For an experienced clinician, there is a great deal that can be learned from analyzing a full EKG, but for our purposes, we are first going to look at what is recorded on the EKG paper during a single normal “lub dub” heartbeat. There is nothing mysterious about this information and there is nothing to really remember in all the details I’m going to give you so you can just relax and allow yourself to learn a bit more about the fascinating organ that sits in the middle of your chest.
As you may recall from biology classes at school, the human heart has four chambers, consisting of two upper chambers called atria, the left and the right. The word “atria” comes from the Latin word atrium meaning an open "central court of an ancient Roman house which contained a basin called the impluvium, where rainwater for the household collected from a special opening in the roof that had sloped sides directing the water to the basin. So your heart’s atria collect blood from the body, much like the atrium of an ancient Roman house collected lifegiving rainwater from the sky. The right atria collect the deoxegenated blood that is coming from the body through the large vein known as the vena cava and the left atria collects the freshly oxygenated blood that is coming from the lungs from the pulmonary veins and will shortly be pushed out to the body’s tissues.
The two lower chambers are known as ventricles, the left, and the right. The word ventricle comes from the Latin word “ventriculus” meaning the belly or pouch. So the ventricular chambers are the belly of your heart. The right ventricle will receive the deoxygenated blood from the right atria which is positioned just above it and is separated by a valve, called the tricuspid, as it has 3 leaflets. The left ventricle receives the freshly oxygenated blood from the left atria, positioned above it as this blood comes through the mitral valve. You can see here in the illustration in this section of the human heart the two muscular thick-walled ventricles on the bottom and the two much less muscular atria on top.
The heart’s chambers are made of special cardiac muscle cells and in a healthy person, they contract in an orderly manner and in a particular sequence. There is also a system of “electrical wiring” so to speak in the heart, which initiates the electrical signal and propagates it to all of the cardiac tissue.
The electrical signal begins in a cluster of cells positioned at the top of your heart known as the SA or sino-atrial node. The SA node is also called the pacemaker, because the rate that it fires determines the rate at which your whole heart beats, and this rate is of course known as your heart rate. So the SA node fires and that electrical signal then very quickly travels down through your heart, initially to the two atria, causing them to contract, which causes blood to flow into the two ventricles below.
By this time, the electrical signal has reached the bottom of the right atrium where there is another group or node of cells called the AV or atrio-ventricular node. Now the ventricles need time to fill with blood before they get the signal to pump, so the AV node momentarily slows down the signal until the ventricles are full, then it fires. The signal travels down a path of cellular wiring called the bundle of His which then divides into a branch that goes to the left ventricle and one that goes to the right ventricle. These branches are then even more finely divided and spread throughout the ventricles.
So now the electrical signal has come down from the AV node through the bundle of His and has spread to the ventricles, and causes them to contract. The right ventricle pumps blood off to your lungs to be oxygenated and the left ventricle pumps oxygenated blood out to the rest of your body.
Of course, when the atria pump blood into the ventricles through open valves, these valves must close before the ventricles pump out the blood; otherwise, the blood would backwash into the atria. So the closing of the valves that separate the chambers of the atria from the ventricles is accomplished by a buildup of pressure in the ventricles, closing the two valves and making the “lub” of the first heart sound.
Then, when blood is pumped from the ventricles out to the lungs and to the rest of the body, the valve that separates the right ventricle and the pulmonary artery going to the lungs (the pulmonary valve) and the valve that separates the left ventricle from the aorta, the aortic valve, going to the rest of your body, once that blood has been pumped out, those valves must close as well to prevent backflow of blood into the heart. The closing of these valves causes the second heart sound. Once the atria and the ventricles contract and then relax, each part of the heart’s electrical system resets itself and the cycle begins again.
Now that you have some idea about the electrical goings on in your heart and how they drive the circulation of blood in your body, let’s look at how these electrical events translate to the markings on EKG paper. The heart happens to be the most powerful source of electromagnetic energy in your body and produces the largest rhythmic electromagnetic field of any of your organs. Your heart's electrical field is about 60 times greater in amplitude than the electrical activity generated by your brain and it’s this electrical field that the EKG sensors are recording.
Here is a normal EKG tracing and the metal instrument in the photo is a pair of metal EKG calipers, used to measure the timing of different parts of the cardiac impulse. Let’s pull out a single heartbeat tracing, so to speak, in the photo that would be the parts from one tip of the caliper to the other, and get a closer look.
So what you are seeing now is known as the QRS complex, named after the major waves that comprise it. And you can see there is some stuff that comes before and after the actual QRS waves that make up this, so the whole thing is known as the QRS complex.
You will see that the various portions of the EKG are labeled according to the name of the wave and the others are just names for various intervals within the cardiac cycle.
The cardiac cycle is initiated by the pacemaker SA node and the P wave represents atrial contraction. Then you will see there is a pause (the PR interval) allowing the ventricles time to fill with blood. This is not a long time and is measured in milliseconds.
Then we have the actual QRS complex, the Q wave in orange going down and up, then spiking way up as the red R wave and then down and up as the blue S wave at the bottom.
These three waves, Q R and S, occur in rapid succession. This QRS complex represents the electrical signal as it spreads through your heart’s ventricles and it begins just before the ventricles begin to contract.
The blue T wave represents the resetting of the electrical system of the ventricles, after the contraction and relaxation of the heart. The atrial resetting occurs back in the P wave area but its signal is so small that you can’t see it.
So now, when you look at a normal EKG tracing, you can see and recognize all of these individual QRS complexes, one following the other, which represent the electrical activity of the heart, together with the underlying contraction and relaxation of the chambers and of course this occurs in an orderly fashion in a healthy person. These various intervals, the PR interval and the QT interval and so forth are not rigid in terms of their length, meaning the time they take to occur, but they all have ranges of normal.
There is another interval which is the interval between the peaks of the R waves, this is called the R-R interval and is the space between complete heartbeats. And just like all the other intervals, it’s not rigid in length either, but has a range of normal.
We all know that a “regular’ heartbeat is a healthy heartbeat. You don’t want to go to the doctor and have the nurse take your pulse and go uh oh, how long has your heartbeat been irregular, or you have been having frequent palpitations or skipped beats, as that could indicate some sort of cardiac rhythm problem.
But the truth is, that macroscopically, in the big picture, if you are healthy your heartbeat is regular. But at a more microscopic level, when you actually measure in milliseconds between the peak of one R wave and another, the distance will vary every so slightly, between one R wave and the next. In fact, if this interval, the variation in time between heartbeats, which is what heart rate variability is…if this becomes fixed and rigid, this is known as a loss of heart rate variability.
So what controls heart rate variability? HRV is controlled by your autonomic nervous systems. If you remember from biology class, your autonomic, or as I like to call it, your automatic nervous system, is divided into two parts, the sympathetic and parasympathetic. The sympathetic system is responsible for the “fight or flight” reaction we commonly have to stress, and in terms of its effect on the heart, has its foot on the heartbeat accelerator so to speak and the parasympathetic system is responsible for the relaxation of bodily systems, and so it puts on the brakes and slows the heart down.
So if your body systems are constantly in more of a fight-or-flight state, the variation between heartbeats tends to be lower, a low HRV. If your system is in a more relaxed state, the variation between beats may be higher, a higher HRV. The autonomic nervous system’s job is to strike a balance between sympathetic and parasympathetic, with input from each system keeping your heart’s activity responding within a range that reflects what is going on in your body. So HRV sort of functions like a window that we can use to look into our autonomic functioning and see how it's doing.
HRV is also an indicator of how well you are aging. Your HRV is greatest when you are young, and as you get older, it naturally declines. But having an abnormally low HRV for your age group is not good and could indicate coming health problems or even be a predictor of premature death.
When it comes to measuring HRV, there are all kinds of apps and tracking devices on the market, such as the Apple Watch and the Oura Ring which is pictured here, but the most accurate way would be to use a long-duration EKG recording in a lab, but at-home monitors don’t have those. The Oura Ring website claims high accuracy for its HRV measurements.
But you really shouldn’t get too caught up in the numbers because different devices have different units they use and different methods of calculating, so you will need to read and follow the recommendations for your particular device on how to interpret the readout. So you could track your HRV over time and see how it changes in response to a particular period of stress or illness, or how it changes with exercise, sleep, meditation practice, and so forth. It’s really the long term trend in HRV that is important and not the absolute reading in terms of a number.
The things that you can do to improve your HRV are many of the same things that you can do to improve your overall health, such as regular exercise, especially giving your body time to rest and recover in between…staying hydrated, also avoiding alcohol as it’s been shown that just one evening of drinking can negatively affect your HRV for up to five days. Also, of course, a healthy diet and quality sleep plays a part and aligning your circadian rhythm so you are waking up and going to bed at the same time every night. Stress control is important as well. All of these can help.
But aside from lifestyle changes, you can also take up HRV training.
This is where we want to bring your attention to the work the HeartMath company is doing, because they became interested in how our emotions can affect heart rate variability. They plot out HRV over time to give a picture of the heart rhythm waveform. This is very different from the EKG pattern we have been looking at.
Their research shows that when we experience a negative emotion, such as anger, anxiety or even if we are feeling frustrated, the signals coming from the sympathetic and parasympathetic systems get out of sync. This produces what they call cardiac incoherence, which is a chaotic pattern.
On the other hand, positive emotions, such as love, compassion or appreciation, produce a coherent waveform pattern. HeartMath is quick to point out that cardiac coherence is not the same as relaxation and does not necessarily involve a lowering of the heart rate. Coherence is experienced as a calm, yet energized and responsive state where you can function at your best.
This is important because we were always taught that the brain sends signals to the heart and this was a one way street. But now, research has shown that the heart sends signals to the brain as well, and these signals influence all kinds of brain activity including attention, memory, perception and problem-solving. I know I would rather be sending a coherent signal to my brain rather than a chaotic one.
Quick Coherence Technique
Slowing one's breathing can help to shift you into cardiac coherence but it’s difficult for many people to maintain. Heartmath focuses more on the intentional generation of heartfelt positive emotions to shift people into this state. This is the Quick Coherence technique that they say will produce cardiac coherence in as little as 60 seconds. I need to point out that this term is trademarked by them, but they make instructions on how to do it freely available on their website. So you can try it right now.
The first thing to do is to focus your attention on the area of your heart. Now, simply begin to breathe a little slower and a little deeper than usual while you are doing this and just imagine your breath is flowing in and out of your heart or chest area. Some people like to place their hands, palms down, on the chest area while they are doing this.
Now, just let the awareness of your breathing fade into the background and make a sincere attempt to experience a heartfelt positive feeling such as appreciation or care for someone or something in your life and just hold that positive feeling for a just a bit…
And that’s it!
Heartmath also has some tech tools…an app with a sensor called Inner Balance that you can use to learn how to regulate your cardiac coherence and you can actually see and chart your progress. You can get a look at those at HeartMath.com and also get an overview of their research at HeartMath.org.
So I hope you come away from this with a new heartfelt appreciation for what a powerful and complex organ your truly heart is.
Why It Matters
“Variability is the law of life…”
~ William Osler (1849–1919) - Sir William Osler, was a Canadian physician and one of the four founding professors of Johns Hopkins Hospital. He was the first to bring medical students out of the lecture hall and to the actual bedsides of patients for clinical training.
What We Are Reading 📚
Denise - I’ve been reading The Community Cure by James Maskell as I prepare for a wellbeing event I’ve been working on with a client. For years, Maskell has advocated for changes in healthcare systems to include group — community — practices for treating chronic diseases. He asserts that when people are educated and treated in a community-based setting, the “disease of loneliness” is treated, empowering individuals to implement lifestyle changes and improve their health.
Ellen - I first read The Alchemist, Brazilian author Paulo Choelho’s marvelous, magical tale, many years ago, and to tell you the truth, I had nearly forgotten what it was all about. But sometimes, books seem to come back into our lives when we need it most. A few weeks ago, a good friend sent me this quote from The Alchemist:
“Before a dream is realized, the Soul of the World tests everything that was learned along the way. It does this not because it is evil, but so that we can, in addition to realizing our dreams, master the lessons we’ve learned as we’ve moved toward that dream. That’s the point at which most people give up. It’s the point at which, as we say in the language of the desert, one 'dies of thirst just when the palm trees have appeared on the horizon.”
This was the perfect message for me at that moment and I was so taken with it’s wisdom that I decided to read The Alchemist once more. But this time, I listened to the audiobook version, perfectly narrated by the legendary English actor Jeremy Irons.
Published in 1988 and translated from its original Portuguese, the book quickly become an international bestseller and an instant classic. Have you read The Alchemist? If so, I’d love to hear your thoughts about the book in the comments!
Did you like this article and learn something new? If so, please let us know in the comments! Questions and suggestions for future articles are welcome, too!
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