October 15, 2019
I'm not really as big of a self-quantification geek as you might suspect. Aside from attaching the occasional 24/7 blood glucose monitor (pictured above) to my body and wearing an Oura ring (also pictured above), I spend the majority of my time “unplugged”—even while exercising, and have been since about eight years ago when I wrote this article about listening to your body.
When it comes down to getting all the nitty-gritty details about what's going on inside my body, I try to limit my use of most of the self-quantification tools for multiple reasons, including a deeper connection to nature when exercising outdoors, less WiFi and Bluetooth strapped to my body while I'm working out, and the simple fact that I do lots of high-intensity functional exercise and stuff just inevitably snaps and breaks during workouts.
However, there is indeed one metric I track regularly—always in the morning for five minutes while lying in bed, or occasionally when I'm trying something new (such as a new exercise or supplement or breathing strategy) and want to see in real-time how it's impacting my nervous system. It allows me to gain insight into how well my body has recovered, and thus the level of intensity my body is capable of training at for the rest of the day—I take a 5-minute measurement to determine my heart rate variability (HRV).
An entire book could be devoted to the topic of HRV (by the way, I do devote a huge chunk of my new book, Boundless, to this topic), but even a basic understanding of how heart rate variability tracking works can tell you exactly how stressed your nervous system is, how prepared your body is to train, and how everything from stress, supplements, sleep, sex, and beyond can affect your body.
In today's article, I'll give you a crash course on what HRV is and why it's so important to have this data handy in the first place. You'll also discover how I determine—with laser-like accuracy—how recovered my body actually is after a grueling workout, as well as my go-to methods for quickly elevating my HRV so I'm more prepared to handle any stress life may throw at me, including airline travel, hard workouts, competition or even a long day at a conference.
What Exactly Is Heart Rate Variability (HRV)?
It all starts, as you may have guessed, with the heart. The origin of your heartbeat is located in what is called a “node” of your heart—in this case, something called the sino-atrial (SA) node. In your SA node, cells in your heart continuously generate an electrical impulse that spreads throughout your entire heart muscle and causes a contraction.
Generally, your SA node will generate a certain number of these electrical impulses per minute, which is how many times your heart will beat per minute.
Your SA node initiates the electrical impulse that causes a contraction to propagate from the SA node to the left and right atria causing the atria to contract and expel blood into the right and left ventricles. As the electrical impulse spreads from bundles branches to the right and left ventricles, they contract and force blood out into general circulation. (See diagram below.)
So where does HRV fit into this equation?
Your SA node activity, heart rate, and rhythm are largely under the control of your autonomic nervous system, which is split into two branches: your (rest and digest) parasympathetic nervous system and your (fight and flight) sympathetic nervous system.
Your parasympathetic nervous system influences heart rate via the release of a compound called acetylcholine by your vagus nerve, which can inhibit activation of SA node activity and decrease heart rate variability.
When the parasympathetic nervous system is activated, it releases acetylcholine to induce a low heart rate and a state of relaxation. Your HRV will be highest at this point, so a high HRV indicates a low state of stress.
In contrast, your sympathetic nervous system influences heart rate by the release of epinephrine and norepinephrine, and generally increases activation of the SA node and increases heart rate.
If you’re well-rested, haven’t been training excessively, and aren’t in a state of over-reaching, your parasympathetic (rest-and-digest) nervous system interacts cooperatively with your sympathetic (fight and flight) nervous system giving you really nice, consistent, and high HRV values.
The Importance Of Tracking HRV
Measuring your HRV is one of the best ways to know if your body is stressed. Generally speaking, the higher your HRV, the better, although there are some exceptions to this rule, which I get into in this podcast and this podcast (remember, transcripts are always available if you click on those links). My personal goal is a value of around 90, which I typically see every day.
On the contrary, if you’re overtrained, not well-rested, or sleep-deprived, the normally healthy beat-to-beat variation in your heart rhythm begins to diminish, thereby indicating a low HRV.
Abnormal variability—such as consistently low HRV values (e.g. below 60) or HRV values that tend to jump around a lot from day-to-day (70 one day, 90 another day, 60 the next day, etc.) would indicate that the delicate see-saw balance of your sympathetic and parasympathetic nervous system no longer works.
Here is an example of measurements and fluctuations I saw when measuring HRV during a time that both my lifestyle and exercise stress significantly increased as I approached a big race…
Tracking your HRV allows you to see if you are overstressing your body, producing excess cortisol, or becoming weight-loss resistant.
Once you begin tracking your HRV values, you can start to see trends after rest days, overtraining, stress, etc. and take measures to increase your HRV. In my experience, some causes of low HRV—aside from overtraining—are poor diet, bad breathing, relationship and work stress, poor air quality, excessive artificial light exposure, electrical pollution from WiFi and Bluetooth signals, and impure water.
Closely monitoring my HRV and addressing each of these variables in my own life over the years is how I've come to achieve a consistent HRV of 90+, even during stress and travel, with the only exception to that rule being when I purposefully “overreach” to achieve a supercompensatory training response during the rest that occurs after the overreaching.
4 Tips For Raising Your Heart Rate Variability
A few years ago, during the final three weeks of training for an upcoming triathlon, I didn’t allow myself a single recovery day, and it finally caught up to me in the form of a shockingly low HRV score.
I had an overtrained parasympathetic nervous system that needed some serious adjustment if I was to be ready to race.
Rather than arrive at the starting line feeling worn down, beat up, and overworked, I was able to quickly recover and see my numbers come back up within 5 days by using the following four strategies:
1. Cold Exposure
Cold immersion has been proven to lower inflammation and markers of inflammatory damage such as CRP or interleukin—which allows the body to bounce back faster from an overreached state. I began full-body immersion in a nearby river that typically runs 40-45° F for 20-30 minutes a day, 1-2x/day (you can also achieve this in an ice bath if you live in a warmer climate without access to a cold body of water). I combined this with wearing 110% compression tights and shirt filled with ice sleeves while I was sitting at home working (although since that time, I've found the CoolFatBurner vest, which I think works better).
2. Adaptogenic Herbs
I use a Chinese Adaptogenic Herb complex called Tian Chi, and I began to double dose on an empty stomach 1-2x/day, in mid-morning and/or mid-afternoon. The ingredients of Tian Chi include compounds that help to relieve adrenal gland stress and support proper adrenal function, including ashwagandha, eleuthero, epimedium, and Gotu kola. These types of compounds are incredibly effective at restoring function to your adrenal glands when you’ve been asking yourself to churn out adrenaline, epinephrine, norepinephrine, etc. with day after day of hard training. I don't think you need to use adaptogens day-in, day-out all year long but they're useful if you've “dug yourself into an HRV hole”, so to speak.
3. Deep Sleep
During deep sleep, your body releases large amounts of growth hormone for repair and recovery, and initiates cellular turnover that can speed up the removal of “junk” from a taxed musculoskeletal system. Once I saw my HRV score drop, my goal was to get myself into a deep sleep phase as quickly as possible, and I did this by using a PEMF device called a BioBalance to activate my “deep sleep” Delta brain waves, along with sleeping in a very dark room, using 60-100mg CBD before bed (as I elucidate in this recent Instagram post), and making sure to use my blue-light blocking glasses at any point after 4pm in the afternoon. This article is a great resource with even more tips for getting restorative, deep sleep.
4. Anti-Inflammatory Diet
Because they result in a net acidic load when you metabolize them, pro-inflammatory foods will increase inflammation and increase your pain from the inflammation. These include processed meats, foods high in omega 6 fatty acids like roasted seeds and nuts, pastries and cereals, starches, and even nightshade plants like regular potatoes, tomatoes, and eggplant. When you’re injured or overtrained and looking for every available advantage, you should instead prioritize foods with natural anti-inflammatory properties, like dark-skinned fruits and vegetables (pomegranates, cherries, blueberries, plums, artichokes, spinach, and broccoli are excellent), high amounts of omega-3 fatty acids (cold-water fish, cod liver oil, fish oil, etc.) and natural herbal anti-inflammatories like turmeric, curcumin, garlic and ginger. And yes, I quit alcohol and high amounts of caffeine during that time too.
At the end of the five days, I ended up recovering, having my heart rate variability score sore back up, and setting a personal race record at the triathlon. Sure, there are other things that can improve HRV, such as breathwork, meditation, yoga, etc., but in this case, I used the combo of cold, adaptogens, deep sleep, and an anti-inflammatory diet approach.
When A Low Heart Rate Variability Isn't Necessarily Cause For Concern
Abnormal variation can indicate a serious stress issue, especially if you see consistently low HRV values (my personal red flag metric is any HRV value below 80, unless I’m purposefully training myself very hard for a competition and in an overreached state) or values that jump around from day to day.
Despite this, a lower HRV does not always necessarily forecast impending reductions in performance.
According to one study, tennis players who had followed 30 days of over-reaching and getting very close to over-training by significantly decreasing their HRV actually saw an improvement in performance.
So if you are training, you can intentionally reduce your HRV by over-reaching and training yourself a little bit harder than usual. As long as you worked in some smart recovery tactics, that low HRV can actually come back to help you as long as you are able to get it back up.
Another situation in which you may see a consistently low HRV would be in athletes who engage in high amounts of sympathetic nervous system training and low amounts of parasympathetic nervous system training. Think CrossFitters, sprinters, World's Strongest Man competitors, people who are doing a relatively low amount of aerobic training.
You can read more about how a low HRV isn't always bad (and a high HRV isn't necessarily always good) in this article.
For most of us though, the goal should be to strike a balance between sympathetic and parasympathetic nervous system training. You can learn how to do that and build a more robust nervous system in my article “Bigger’s Not Better – Your Ultimate Guide To Brain Training For The 1-2-3 Combo Of Power, Speed & Longevity.”
So What's The Best Way To Test & Track Heart Rate Variability?
When it comes to self-quantification in real-time (which is different than the ongoing self-quantification you might get from something like a WHOOP wristband or Oura ring, there are a ton of devices out there for tracking HRV, and I've experimented with just about every one of them. The reason one would want to track in real-time is to get instant feedback on both sympathetic and parasympathetic nervous system interplay, which can be far more insightful than just a single glance at overall HRV such as you would get from a wristband or ring.
My top recommendation for this type of real-time HRV measurement is the NatureBeat Heart Rate Variability Tracker system.
With the help of Jo Beth Dow—co-founder, CTO, and COO of SweetWater Health, LLC, pioneer in the use of heart rate variability as a platform for remote monitoring and diagnostics, and previous podcast guest on the episode, The Best Way To Know How Stress, Supplements, Sleep, Sex & More Affects Your Nervous System: The Latest News About Heart Rate Variability (HRV) Training, I developed the NatureBeat system to fill a void I saw in the HRV tracking space.
NatureBeat is a clinical-grade HRV tracking app that puts an end to yo-yo (120 on one device, 100 on another, inconsistent HRV measurements, etc) HRV results. Its easy-to-use, intuitive interface allows you to track your heart rate variability in real-time (such as when you’re out on a run or working at your office or trying out some new exercise, supplement or breathwork routine, or just want a highly accurate one-time morning check-in on HRV).
The NatureBeat system measures:
- Heart Rate
- Heart Rate Variability
- Skin temperature
- Steps and activity
There's even a food sensitivity test. After taking a morning reading of your pulse to establish a baseline for the day, and before eating a meal, you record the foods comprising the next meal and perform a pulse test. After you have finished eating, the app will prompt you to record your heart rate every 30 minutes until 90 minutes have passed. Once testing is complete, the meal will either pass or fail for food sensitivity.
This app also integrates and correlates data with popular fitness platforms like Restwise, MapMyFitness, Fitbit, and Withings. The next big thing in biohacking is to understand the information presented in the data that you track every day, and this is a perfect way to do it while getting many valuable metrics all at once like HRV, stress, heart rate, weight, steps, calories, and much more.
The Monitor screen (pictured left) allows you to choose which feature you would like to use (Stress Monitoring, HRV for Training, or Heart Rate Recovery). After starting a session, your metrics will fill the screen and include heart rate, HRV, stress level, and current mood.
The EKG-like heartbeat trace is the first window you see when you begin tracking on the Monitor screen. By flipping this window around, you can see several other real-time features, including the stats screen (more widely referred to as the “geek” mode screen) which shows all the metrics used in the algorithm calculations and then some!
If using the HealthPatch (available as a patch you can stick on your body, which you can order straight from inside the app once you download it), you can then go on to monitor your respiration, energy, skin temperature, steps, and activity.
The graph screen shows a real-time building graph of your heart rate from what are called “RR Intervals.” Turning the phone 90 degrees counter-clockwise will bring up this graph in landscape, and gives you real-time feedback about your heart rate activity. This is the future of noninvasive monitoring of cardiovascular and nervous system health and performance!
The correlation screen uses a patent-pending algorithm to correlate all of the data you share with NatureBeat from something like a FitBit, Withings, Restwise, or MapMyFitness. Settings allow you to view demos or analyze the correlations between their own data. You can then choose which metric you want to correlate to the others (HRV, stress, or weight). You can choose to see all of your data or put in specific date ranges.
In competitive sports, improved performance is achieved by alternating periods of intensive training with periods of relative rest. NatureBeat uses patent-pending algorithms to create a personalized reference line for you based on 3-minute daily HRV readings. Just like your own personal coach or physician, the app recommends you to “train as usual,” have a “low exertion day,” or take a “rest day.”
The NatureBeat phone app needs to be combined with a compatible monitoring device. You can use any of the following, which you can get on Amazon (I personally use the Viiiva model).
- 4iiii Innovations V100 viiiiva Heart Rate Monitor V100
- Armour39® Module & Chest Strap
- Zephyr HxM Smart Heart Rate Monitor for iPhone 4S, iPad (3rd Gen) & iPhone 5 with Bluetooth Low-Energy (4.0)
- 60beat Heart Rate Monitor for iPhone, Android & ANT Plus Devices, Black
- Pear Sports Mobile Training Intelligence System for iPhone 4S, iPhone 5, iPhone 5S and iPhone 5C
- Wahoo TICKR Heart Rate Monitor, Bluetooth/ANT+
- Polar H7 Bluetooth Heart Rate Sensor & Fitness Tracker
- Polar H10 Heart Rate Monitor
- SUUNTO Smart Sensor – AW16
HRV can get even more complex than a simple 0-100 number.
For example, when using an HRV tracking tool like NatureBeat, you can also track your nervous system’s low-frequency (LF) and high-frequency (HF) power levels.
This is important to track for a couple of reasons:
- Higher power in LF and HF represents greater flexibility and a very robust nervous system.
- Sedentary people have numbers in the low 100s (100-300) or even lower, fit and active people are around 900–1800 and so on as fitness and health improve.
Tracking LF and HF together can really illustrate the balance in your nervous system. In general, you want the two to be relatively close. When they are not, it may indicate that the body is in a deeply rested state with too much parasympathetic nervous system activation (HF is high) or in a stressed state with too much sympathetic nervous system activation (LF is high). (For a more detailed explanation of this chart, read this blog post)
If you want to learn more about LF/HF and why it's important, listen to my podcast, “Episode #222: What Is The Best Way To Track Your Heart Rate Variability (HRV)?” It will really elucidate this whole frequency thing for you. There’s also a follow-up, slightly more advanced podcast that covers power frequency and HRV here.
HRV can obviously be tricky to understand, and there's no one-size-fits-all scoring system. Numbers can vary widely from one person to the next. I've seen elite athletes with an average HRV in the low 40s, and professional athletes with average scores in the mid 100s.
A number of factors such as age (that's a big one), gender, lifestyle, hormones, and fluctuating variables like emotional and physical stress can contribute to your HRV score.
The good news is that there's plenty you can do to raise your HRV. Once you've established your baseline, I promise you, as nerdy as this may sound, checking your HRV will become something you'll look forward to every morning. It'll quickly become one of the best tools in your workout and recovery toolbox.
Oh, and if you're ready to dive further into HRV, here's a list of some of my other resources that weren't mentioned in this article:
- Everything You Need To Know About Heart Rate Variability Testing
- The Do-It-Yourself Guide To Using Heart Rate Variability Testing to Track Your Stress and Nervous System Health
- A Deep Dive Into HRV: The Myths & Truths of Heart Rate Variability Testing
- HRV: The Single, Next Big Trend In Biohacking And Self-Quantification And How To Use It.
- 338: How To Lower High Cortisol, The Groundbreaking High-Fat Endurance Study, What Causes Low HRV & More!
What about you? Are you currently tracking your HRV? Let me know in the comments section which tools you're using, any interesting trends you've noticed, or if you have any questions or comments! And if you want to try Naturebeat for yourself, click here for the iPhone version and here for the Android version.