Dr. Jay Wiles, of Hanu Health, joins us to explore what heart rate variability (HRV) is, how it affects the human body, and how to train it for greater stress resilience.
Why Is Measuring HRV Important?
Heart Rate Variability or HRV, as it currently stands, is the single greatest non-invasive proxy we have for examining the dynamic shifts in the autonomic nervous system. It gives valuable insight into how well the nervous system is adapting to stress, both physiological and psychological.
HRV is the single greatest non-invasive proxy that we have for examining the dynamic shifts and changes in the autonomic nervous system.
When our nervous system has the resources to adapt to our environment, we see a stabilization of HRV. However, when the nervous system’s resources are depleted and sufficiently taxed, in other words the stressor is too much to handle, we see this manifest in a lower HRV.
What Types of Things Influence HRV Fluctuation?
The main source of HRV fluctuation is stress, both physiological and psychological. As the body needs to mobilize more energy in times of stress, HRV is significantly reduced. However, as we actively recover and engage in energy conservation, our HRV will regulate to its normal value or even increase from our baseline.
HRV is strongly associated with both blood pressure and breathing. As we change the biomechanics of our breathing and the cadence of our breathing, we can significantly influence a mechanism in our physiology called Respiratory Sinus Arrhythmia or RSA.
Changing our breathing pace influences the heart. This change in heart rate across the respiratory cycle will result in higher HRV. It also will set a cascade of physiological changes that will help with blood pressure regulation.
How Is Heart Rate Variability and Our Mind’s Health Inextricably Linked?
Experiencing psychological stress is related to changes and adaptations in our autonomic nervous system. Numerous studies have demonstrated that as people experience heightened stress, HRV is suppressed. This is because when our perceived ability to adapt and take on stressors is excessively taxed, our nervous system responds by putting up a fight. This results in an overactivation of our sympathetic nervous system (fight-or-flight) and a withdrawal of our parasympathetic (relaxation) response.
Through the secretion of hormones like cortisol and glucocorticoids, alongside dysregulation of areas of the brain that are responsible for the secretion of epinephrine and norepinephrine, we can enter into a chronic state of stress. This leads to a deleterious compounding effect over time, which is manifested in a lower HRV.
Science-Backed Activities Known to Optimize HRV
There are many proven methods of promoting healthy HRV. But we must remember that HRV is a guide and be more concerned with its direction rather than its total number. Far too many people are worried about their baseline HRV, when they really should be more focused on using HRV as a directional guide.
As HRV trends downward, we are seeing signs of nervous system taxation. If HRV is stable, then this is normal, which is what we are looking for. If HRV trends upward, then this can be a sign of nervous system recovery and repair.
The single greatest method for enhancing HRV is HRV biofeedback. HRV biofeedback uses breathwork as the primary tool, but adds the component of being able to see real-time HRV changes that indicate nervous system change. It allows individuals to see the effects of practicing skills like HRV biofeedback and how they can train the nervous system to adapt. The more that we do this practice, the more we learn to help self-regulate our nervous system.
Another amazing tool is meditation. Meditation is a method for teaching present moment awareness and can help to reign in our thinking. Meditation has been shown to affect changes in the nervous system, as evidenced by enhancing HRV.
Health stressors can also optimize HRV. Practices like daily exercise, sauna, and cold exposure can be quite helpful in developing stress resilience and maintaining a healthy HRV. Lastly, good quality sleep is foundational. Without good sleep you will not have good nervous system recovery, suppressing your HRV.
Can Meditation Really Have a Meaningful Effect on HRV?
Absolutely! A study performed in 2019 found that meditation can significantly shift the autonomic nervous system, producing more vagal stimulation, and modulating markers of stress resilience, including multiple metrics of HRV. The more we train with meditation, we see vagal improvements and, as a result, changes in our baseline HRV.
A study performed in 2019 found that meditation can significantly shift the autonomic nervous system, producing more vagal stimulation, and improving markers of stress resilience, including multiple metrics of HRV.
The Link Between HRV and the Vagus Nerve
The vagus nerve, our 10th cranial nerve, is the primary driver of HRV change. It is via the vagus nerve that the peripheral nervous system communicates with the central nervous system to engage in relaxation or withdraw from it.
The vagus nerve is the primary driver of HRV change.
The vagus nerve branches are 80% afferent, which means that most of the communication is going from the body to the brain instead of from the brain to the body via these nerve branches. The vagus nerve innervates (connects to) most organs in the body. When it detects changes in the lungs, heart, and gut, it relays this information back to the brain and spinal cord.
If we consciously slow our breath rate, we effect change in the heart and lungs. At this point, the vagus nerve is triggered and sends a “relaxation” signal to the brain. This will result in the release of a neurotransmitter called acetylcholine, which aids in slowing the heart and regulating blood pressure. The way you can measure this change is through HRV.
Get to Know Dr. Jay Wiles
What books are you reading right now?
I’m currently reading three books: Deep Work by Cal Newport, Discourses by Epictetus, and Brain Energy by Dr. Christopher Palmer.
Marcus Aurelius, “You could leave life right now. Let that determine what you do, what you say, and what you think.”
What is one biohack you cannot live without?
I podcast with Ben Greenfield, so we try just about everything, but my essential biohack is sauna.
Last, do you consider yourself a good sleeper? What helped you become a good sleeper?
I would consider myself a good sleeper, in general. I prioritize sleep as the foundation of my physical and mental wellness. The biggest contributor to high quality sleep is consistency in my routine.
Walk us through your sleep routine from dinner until you hit the pillow. What devices, supplements/teas, tech, textiles, etc. do you use?
Dinner is indeed the last time I eat. Since I have small children, we eat early. I am normally done eating by 6:30pm. So my fasting begins then, which has been imperative for improving sleep. I find that if I stop eating 3-4 hours prior to sleep, that is my sweet spot.
After dinner, I do not touch any form of media other than watching occasional shows with my wife.
Around 7:30-8pm we adjust all of our home lighting to a much lower intensity and in our bedroom we will put redlights only. My wife and I chat for about 30-45 minutes and catch up. This is so important because high quality relationships lead to high quality sleep. During this time, I might sip on some chamomile tea or reishi tea; however, I do try to limit liquids after dinner to avoid waking up and needing to use the restroom.
I am in bed between 9:00-9:30 pm every night, even on weekends. In bed, I will read for about 20-30 minutes and follow that up with 5-10 minutes of HRV biofeedback and/or breathwork with Hanu. I use the “Pre-sleep” training on Hanu and that thing knocks me out! I also sleep with a Chilipad and have it set at 56 degrees. I always sleep with a white noise machine and sleep mask. My other tool is sleep tape. I use it every night and swear by it. As for supplements, I have used different forms of magnesium, theanine, Qualia Night, and apigenin.*
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*These statements have not been evaluated by the Food and Drug Administration. The products and services mentioned are not intended to diagnose, treat, cure, or prevent any disease.
The recommendations in this article are not intended as general medical advice, represent the opinions and experience of the interviewee, and are not a guarantee, promise, or reflection of other users’ results. Consult your physician before making any diet or lifestyle changes.
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