Heart Rate Variability: What is it and why bother improving it?

Photo by Maria Orlova on 


Someone cuts dangerously close to you in traffic, your sympathetic nervous system kicks into gear by dilating your pupils to see available options, increasing heart rate, respiration, and blood flow to muscles so you can react quickly. In a split second you see that if you hit the brakes the car behind you will not have time to stop, but there is no one on your left so you swerve to that lane. The threat is now neutralized but what about your nervous system?

We can have a healthy nervous system response which may look like you taking a few deep breaths, thanking the Universe for the positive outcome and finding a good song on the radio to sing out the tension or maybe, pulling over safely to a stop, closing your eyes and taking several long deep breaths until the fear and shock pass. Both of these examples include neutralizing the adrenaline and cortisol and restoring the parasympathetic brake. 

Or we can have less healthy nervous system response which might include cursing and speeding up to “shake your fist” at the other driver and fuming about the experience for the rest of your drive, arriving at your destination angry and allowing it to ruin your day. In this case, the parasympathetic brake is OFF and sympathetic is driving at brake-neck speed. 

Now, many factors contribute to how you and your nervous system responds, but what is important for this discussion is how we are better able to train our nervous system to have healthy responses to sympathetic input. Like training anything, success occurs when we have measurable objectives to track and target. 

So how can we measure a healthy nervous system, objectively? 

To better understand how resonant frequency biofeedback training can be used to improve cardiac variability, it’s first important to understand resonant frequency, what it means, and how it relates to Heart Rate Variability (HRV). 

Resonant frequency is defined as the oscillation of a system at its natural or unforced resonance and it occurs when a system is able to store and easily transfer energy between storage modes such as kinetic energy vs. potential energy, for example the movement of a playground swing or a simple pendulum. Also described as the phenomenon of increased amplitude that occurs when the frequency of a periodically applied force is equal or close to a natural frequency of the system on which it acts. Makes perfect sense, right? Meh, not so much, huh? 

So what does it all really mean? Steve Mould explains resonant frequency more simply as “getting the timing and frequency just right so that the Energy put into a system ADDS to the Energy already there”(https://www.youtube.com/watch?v=dihQuwrf9yQ) . Taking the playground swing, for example, when you are pushing the child on the swing, you have found the resonant frequency when when the timing and force of the push propels the swing to go higher and higher, rather than those times where you kind of catch them on the tail end of the upswing and you slow them down a bit or just keep the swing at the same speed and frequency.   

“According to Quantum Physics, everything is in oscillation, including heart rhythm, blood pressure, body temperature, energy level and mood. All are related and are constantly in motion and never completely stable.” (Lehrer & Gevirtz, 2014) Because nothing is completely stable, homeostasis is not about finding the “sweet spot” but rather the sweet range. A healthy nervous system is in constant fluctuation and is one that is able to continually respond to its environment. It is the thermostat, not the thermometer. A healthy nervous system is one that is able to sense the incoming stimuli and make the necessary changes to stay in that sweet homeostatic range with enough sympathetic “gas” to keep you moving in life and enough sympathetic “brake” to keep you calm, stable and nourished. 

Biofeedback is an excellent tool to give us objective measurements of what is happening inside of our own bodies. The vital signs the nurse takes at every doctor appointment are perfect examples of biofeedback; heart rate, breath rate, temperature, blood pressure, even height and weight. Activity and fitness trackers also provide useful daily biofeedback measures. Measuring Heart Rate Variability is an excellent way to quantify how adaptable your nervous system is in its responses to stimuli. 

Heart Rate (Cardiac) Variability measures the variance in time between each heart beat. The heart should not beat like a metronome. Variations between heart beats or HRV is an indication of your nervous system’s adaptability and resilience. “HRV is considered a key indicator of aging, cardiac health, resilience and overall well-being” (HeartMath, 2017). Generating a coherent heart rhythm with a resonant frequency of 0.1 hZ has been shown to synchronize the sympathetic and parasympathetic nervous systems. Contrary to previous popular medical and scientific belief, we now know that we can have some conscious control over the Autonomic Nervous System (ANS) and we can do this using, among other biofeedback training methods, techniques that improve Heart Rate Variability. The benefits of having conscious control over your ANS include reduced anxiety and stress, improved ability to respond to stressful events, improved heart and cardiovascular health, lower blood pressure, improved cholesterol profile, improved hormone balance, improved memory and focus, improved exercise performance. HRV training improves every single aspect of your health and well being because the ANS regulates, in some way, every aspect of your mind-body functioning. 

Now that we created a baseline for understanding why the effort is worth your time, here are three simple and short practices to help improve HRV. 

Using your breath is probably the simplest method of creating coherence. The goal is to create coherence between your breath and your heart rate. It has been shown that breathing at a rate of about 6bpm is optimal for most people to generate that optimal frequency of 0.1 Hertz. We can easily and inexpensively monitor HRV using smartphone applications such as HeartRate+ Coherence, InnerBalance by HeartMath and devices such as Spire activity tracker and Polar Heart Monitor (a strap worn around the chest with a Bluetooth monitor) and EmWave by HeartMath. The devices all connect to smartphone or desktop apps which have a breath pacer or they rely on the PPG monitor near the camera on your smartphone. Although the technology behind the apps and devices is complicated, their use is quite simple.  The breath pacer will monitor HRV and guide the length of your inhale/exhale to find your specific breath pace to create resonant frequency or coherence between your breath rate and heart rate. It’s as simple as breathing (mindfully). 

HeartMath Institute has a long standing history of research on this subject and several tools to help improve HRV, some mentioned previously, but they also have several techniques, one of which they call the Quick Coherence Technique (kind of says it all). This technique is fantastic because it is free, easy, does not require any tools or device and can be done ANYWHERE, without anyone knowing you are doing it. 

Step 1: Focus your attention in the area of your heart. Imagine your breath is flowing in and out of your heart or chest area, breathing a little slower and deeper than usual. It helps to count your inhales and exhales. Try starting with a count of 5 in and 5 out and adjust as is right for you.

Step 2: Make a sincere attempt to experience a regenerative feeling, such as appreciate or care for someone or something in your life. Try thinking about someone you love, a pet, a special place or an accomplishment. (HeartMath.org)

Meditation is the third recommended technique. Any consistent practice of meditation will lead to improved coherence. If you struggle with meditation try mantra meditation. Choose a word, sound or mantra, for example the om sound often chanted in yoga classes or the word love, or even just hum. When you notice you’re distracted, return to the sound or mantra. If you prefer a technology assist, consider investing in a Muse2 headband. It is worn across the forehead and has sensors to pick up movement, EEG brainwaves, heart beat and breath pace and is used with an app including guided meditations for each parameter. 

I know, none of these techniques are earth shattering, but please do not underestimate the profound effect of simple. Consistency is the magic. Start with 5 minutes of practice. Every. Single. Day. Build up to build resilience. The daily practice itself reaps unmeasurable benefits, however the real goldmine is that when you practice consistently during times of calm, you train yourself to instinctively use the techniques during times of duress. The body takes charge when the mind cannot. 

Nicole Foras, M.D. 

Where Nature and Science Meet

Author: Nicole

As a physician and wellness coach, I can speak to the stresses of life as a clinician. I help other clinicians break free from the burdens of a stressed out, overwhelmed and frustrated career to live the life of your dreams, reignite your passion of medicine and show patients how to do the same.

Leave a Reply

Your email address will not be published. Required fields are marked *