Hi everyone – I am happy to share an article from an expert in our community.
Dr. John Stenberg will be speaking at our upcoming Biohacking Community Meetup this month.
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Heart rate variability (HRV) is a term that describes an important marker of autonomic nervous system health with significant implications for the performance of the body. The autonomic nervous system (ANS) is a complex system of brain and body processes that help us to regulate internal processes in response to external conditions. In this article we will discuss the utility of HRV as a way to measure the physiological effects of “bio-hacking” practices and inform individuals on the performance of their nervous system.
The ANS involves the sympathetic (“fight or flight”) and parasympathetic (“rest and digest”) branches of the nervous system. Its job is to automatically respond to changes in your environment to keep your body safe and healthy.
For example, if you walk outside and it’s blazing hot, your ANS will trigger a sweat response to provide cooling and maintain internal body temperature in normal ranges. If it’s freezing cold, the ANS will engage a shiver in order to stimulate muscle contraction and create heat, again with the goal to regulate internal body temperature based on external conditions. One of the keys with the ANS is that it’s largely unconsciously controlled – it all happens automatically. Day by day, moment by moment, your ANS is vigilant to keep body systems regulated and adaptable to change. Adaptability is the key term for you to remember.
Image: (Front. Cell. Neurosci., 28 February 2023 Sec. Cellular Neuropathology Volume 17 – 2023 | https://doi.org/10.3389/fncel.2023.999253)
You might then wonder, if these processes are unconscious, what influence do I have in enhancing the performance of the ANS? That’s where “bio-hacking” comes in! As you implement new practices and habits, you may not have realized that you’re priming and strengthening the adaptability of the body by challenging the ANS. Let’s explore and example following the temperature theme.
Cold exposure has been studied using HRV as a tool to measure the parasympathetic (rest and digest) branch of the ANS. Through some complex mechanisms, the external stressor (cold exposure) creates a cardiovascular effect by way of the ANS. In other words, the external condition (cold water) stimulates the ANS to rush blood to the brain and torso in order to preserve organ health in an intense environmental condition. HRV can measure how quickly and efficiently the ANS responds in this way, and give you simple metrics to understand how well your body is performing without having to understand all of those complicated physiological pathways.
Adaptable = healthy
Non-adaptable = unhealthy
Now that we’ve laid the groundwork, let’s quickly summarize before moving onto HRV measurements:
- The ANS is responsible for adapting the internal conditions of the body to the external conditions of the body
- Bio-hacking practices alter the environmental conditions inside and outside of the body for increased health and performance
- HRV is a tool that you can use to measure the performance of the ANS, and subsequently the impact of your bio-hacking practices
Heart Rate Variability for Dummies
You’re not a dummy, but let’s briefly explore what HRV actually is, and how it informs you about your health.
As the name implies, there is variability in the rate and rhythm of your heart beats. If you run, your heart speeds up. If you mediate and perform deep breathing, it slows down. In day to day life, this is happening automatically innumerable times based on the body’s requirements. This is a normal, healthy process. It’s flexible, adaptable, and always changing – in healthy conditions. We often see this variability decrease in chronic disease, which tells us that the body is losing its ability to keep up with the changes in its environment. In fact, low HRV has been associated with “all cause morbidity and mortality” – which basically means that sickness and death are closely associated with a weakened autonomic nervous system.
What we want = strong/healthy ANS with high HRV
What we don’t want = weak/unhealthy ANS with low HRV
What does HRV measure?
HRV measures your heart rate, more importantly the space in between your heart beats. As we stated earlier, this space should increase and decrease depending on what the body needs.
The heart doesn’t beat like a metronome, this is what “variability” in your heart rate looks like. As a biohacker, it gives you a reference point for how well you are adapting to your strategies.
For example, if you initiate a new sleep hygiene practice, you can use HRV metrics as an outcome assessment tool. Seeing positive trends in your HRV toward more adaptability? Good! That means that the change you implemented is objectively increasing body performance, nervous system function, and overall adaptability. The organism who is best adapted to its environment is the one who survives and thrives!
So how do you actually measure and interpret HRV?
There are a number of consumer devices available, and I’ll briefly compare and contrast some of the top devices so that you can choose the right fit for you.
There are different categories of HRV wearable tech, and different data acquisition methods. Electrocardiography (ECG) is the BEST way to capture the data used to calculate HRV, but this is both inefficient and commercially unavailable. Most commercially available devices use photoplesmography (PPG) to accumulate data. This is the technology used in a pulse oximeter, and although more prone to artifact and error in data “cleaning”, it provides efficient access to decent data for the purposes of most enthusiasts.
HRV4Training – uses the camera on your phone to measure HRV through your fingertip. The daily measurement is also correlated with physical fitness parameters to measure recovery trends, readiness to perform, etc. $9.99 app purchase
Whoop – this is a wearable wristband (similar to a fit bit) that emphasizes trends in sleep, recovery, and strain. $239-399 OR $30/month
Oura Ring – wearable ring that also monitors trends in sleep, stress, and resilience. Tracks exercise activity. Discreet, looks like a ring. $250-$550 for device plus $6 membership
Heartmath Institute – takes more of a “consciousness/coherence” approach integrating mental and physical health through HRV biofeedback. $179-$500 with software/hardware combo
Keys with measuring HRV
CONSISTENCY. Wearables like Whoop and Oura ring will take continuous measurements throughout your day, just keep the device on and follow the manufacturer’s instructions. HRV4Training needs to be measured first thing in the morning, and takes 60 seconds.
Interpretation
The good news is, interpretation is done for you with these devices! When I used HRV in my office a few years ago, I had to take a 5 minute continuous reading, export the raw data into a secondary software, and then extract the statistical analysis to interpret. I was juggling terms like RMSSD, HF/LF ratio, SDNN, and so on. It was cumbersome. Now all you need to do is open your cell phone application and you’ve got data interpretation at your fingertips.
Most use some variation of a “recovery score” to inform you on your physiological readiness to perform. You can pull back and rest a bit if that’s indicated, or push hard if you’re well recovered. Either way, you can make data-informed choices that are based on trends in YOUR physiology.
As a broad overview, I hope to communicate a few key points in this brief article:
- The health of your autonomic nervous system is PARAMOUNT for longevity, physical, and mental performance
- HRV is a valid and reliable assessment of autonomic nervous system function
- Better HRV scores correlate to a more adaptable nervous system
- You can measure HRV daily to observe trends in your own nervous system health with discrete, robust technology
- Armed with this information, you can pick and choose strategies that best serve YOU in your bio-hacking pursuits
-Dr. John Stenberg with Zenith Upper Cervical Chiropractic, located in Colorado Springs, CO
