If you’re familiar with the biohacking movement that’s rapidly growing in popularity, you know that modern technology is becoming very impressive. Moving beyond just using technology to improve worldwide communication and automate many tasks to save us time and energy, forward-thinking innovators are discovering and inventing ways to utilize technology to become more informed about our state of health, and to improve it in many ways.
One of the most fascinating innovations bridging technology and health are the various types of health trackers available. They are usually wearable devices with highly sensitive instrumentation that can read and interpret the continuous fluctuations in various health biomarkers, including our sleep cycles, body temperature, resting heart rate, blood oxygen levels, and a particularly complex biomarker known as heart rate variability (HRV).
This article will focus specifically on the topic of heart rate variability, as it’s an incredibly complex measurement that requires a thorough understanding to be able to interpret accurately. Once you know how to read it, you can access a treasure trove of information about how your own personal health and well-being is affected by many internal and external factors on an hourly, daily and long-term basis.
What is heart rate variability?
Heart rate variability measurements record each beat of our heart, and the milliseconds that elapse between each heartbeat. Contrary to a common assumption, our heart should NOT beat like a metronome, at the exact same intervals all the time, if we are in optimal health. A healthy heart actually beats in a highly variable pattern, as our body responds promptly to a massive number of internal and external cues on a moment-to-moment basis. The ability of our heart to easily change its pace to adapt to these cues signifies resilience, adaptability and deep energy reserves.
Even though the pacemaker of our heart (the sinoatrial node) is programmed to keep our heart beating at a consistent pace, another bodily system directly modulates (slows down or speeds up) this otherwise steady rhythm: the autonomic nervous system (ANS). The ANS is a component of our peripheral nervous system that regulates involuntary processes in the body, including heart rate, blood pressure, respiration, digestion and arousal. It continually receives information from our body and environment, and responds by either stimulating or inhibiting various bodily processes.
The ANS consists of sympathetic and parasympathetic divisions. The sympathetic nervous system, popularly known as the “fight or flight” state, is triggered anytime our body perceives a threat in our environment. The intensity of the response exactly correlates to the severity of the perceived threat. The sympathetic nervous system increases our heart rate, constricts blood vessels, dilates our pupils and airways, stimulates sweat production and glucose utilization, and inhibits salivation and digestion (and turns off the appetite).
The parasympathetic nervous system, known as the “rest and digest” (and heal) state, does the exact opposite: it increases feelings of relaxation and well-being, slows breathing and heart rate, and stimulates normal digestive processes. The body defaults to a parasympathetic state when it perceives that it’s in a safe and secure environment, and resumes all normal and necessary bodily maintenance functions.
The nerves that control the sympathetic and parasympathetic systems are linked directly to the pacemaker of the heart, and will automatically speed up or slow down the heart rate to a small or large degree as needed to match the situation at hand.
It may be easy to oversimplify this and conclude that anything that triggers the SNS (sympathetic nervous system) is bad for our health, and anything that triggers the PSNS (parasympathetic nervous system) is good for our health, but this is not really true.
We know that short term exposure to certain types of stressors is actually good for our health, as long as it’s not in excess of what our body can effectively recover from. Exercise is a great example, as it’s a type of stress that increases our resilience and abilities by stimulating the production of additional muscle tissue. When a load is put on the muscles that the musculature is unable to bear easily, the body perceives this as a need to build additional functional mass for the next time it encounters a similar challenge. Consistently challenging the body with this type of stress actually creates micro tears in the muscle tissue, but as long as the challenge is followed by adequate rest and nutrition, the muscles are rebuilt with more strength and density. Short term, controlled exposure to certain types of stress is called hormesis, and when approached intelligently, results in considerably more resiliency and overall health.
Coming back around to the topic of heart rate variability, this is exactly why we want these variations in our heart rate over time. As we encounter a variety of stressors over the course of days, months and years, the body will always do its best to react quickly to the source of stress, and then recover fully, if given the opportunity. A quick, appropriate reaction to stress will often register an immediate increase in our heart rate, and once the stress has passed, a healthy nervous system should recover quickly, indicated by a natural slowing of the heart rate close to resting levels. In a less resilient system, the variability will not be as wide, as the system is not very adaptable, and will not be able to respond adequately to either a stressful or restful situation.
How is HRV measured?
Heart rate variability is usually measured by wearable devices that monitor and track your heart rate over time. This may be a chest strap, a smart watch, or even your phone camera, but potentially the best and most convenient device for this purpose is a ring tracker like the popular Oura Ring. It records all the biomarkers listed at the beginning of this article, and whenever you want to see the recorded data, it can be transmitted to a connected app on your phone. You can even keep the device on “airplane mode”, so it won’t be transmitting data via Bluetooth while you’re wearing it (which would increase your EMF exposure), but will still collect and store data that can be accessed as desired.
Heart rate variability is usually measured by a calculation called RMSSD, which stands for “root mean square of successive differences”. It measures the time difference of each successive heartbeat in real-time, and is very effective for transforming lists of numbers into valuable health data.
Usually, heart rate variability and heart rate are inversely correlated: a lower heart rate, since there is more time for wider variations between beats, supports a higher HRV score; whereas a higher heart rate (with less time for variation between beats) leads to a lower HRV score. Any lifestyle factor that improves your heart rate variability will almost always also lower your average resting heart rate. This means that most of the time, increased parasympathetic activity will increase the variance in your heart rate, improving your HRV score. Past a certain point, however, if parasympathetic activity dominates for too long (with very low sympathetic activity), the body and heartbeat will get “lazy” and no longer vary that much, actually decreasing HRV. This is why you can’t get a healthier heart and nervous system by relaxing all the time, and avoiding all sources of stress. Our bodies do thrive on appropriate levels of healthy stressors, balanced by adequate recovery time.
When you’re observing your heart rate variability score over time, you want to see it generally trending towards higher numbers. This doesn’t mean that occasional low numbers are bad, as that may indicate the body reacting appropriately to a short term stressor like vigorous exercise or a challenge at work. Likewise, if you see an abnormally high HRV score (compared to your average), it could also indicate the body attempting to recover from extreme stress, like an accident or very intense, prolonged physical exertion. As you can see, it isn’t a simple metric, as the body is incredibly complex and intelligent in its responses.
As all bodies are different, depending on genetic makeup, age, sex, hormones, illness, emotional state, and lifestyle factors, you can’t really compare your HRV score with anyone else’s. Average “normal” HRV scores vary between 20 to 200 milliseconds, but your personal range will be much smaller. The best way to use this information is to track your own HRV for a period of time, and get to know what’s a normal range for you. Then you can begin to discern what factors affect your score positively or negatively. Some factors known to affect HRV are sleep quality, stress levels, alcohol, stimulants, diet and hydration. You can improve your heart rate variability gradually, over time, by making better lifestyle choices and engaging in controlled forms of healthy stress (like exercise and cold exposure) to increase your resilience. Those who never train or purposely challenge themselves often have lower HRV scores, as the body has not learned resiliency.
Do EMFs affect heart rate variability?
Our body’s heart rate variability is extremely sensitive, and can pick up subtle changes in the environment that are often imperceptible to our senses. There are quite a few studies on the effects of commonly encountered types of electromagnetic fields on heart rate variability in humans and animals. Almost all the studies we have seen show statistically significant changes in heart rate variability, but interestingly, the results seem mixed: some studies show a decrease in HRV, and some actually show an increase. Why isn’t it just one or the other? This is very likely due to the complex adaptive mechanisms of the body, and the short term exposure durations of these studies (of the studies that state the duration of exposure, it was only between 15 and 150 minutes).
Due to hormetic effects (hormesis is explained earlier in this article), acute exposure may have a different effect than chronic exposure to the same stimulus, and sometimes even the opposite effect, especially on a complex biomarker like heart rate variability. If the body has enough internal resources available, the stressor may cause increased heart rate variation as the body attempts to adapt in the initial stages of exposure. If the stressor is continued for a longer period of time, the body’s resources may become exhausted, and the initial HRV increase will lead to an eventual decrease. We would like to see longer term studies on the effects of EMFs on heart rate variability (days, weeks or months), to see how the stats change over time.
All that said, the big takeaway from even these short term duration exposure studies is that the body immediately responded to this invisible, imperceptible stimulus. If EMF levels from modern devices were too low to affect biology, as claimed by the telecom industry, there would be no effect at all, one way or the other! The current body of science on EMFs and HRV is very similar to the neurocognitive studies that we detailed in this article, where the body’s complex adaptive responses sometimes demonstrated a stimulation response, and at other times an inhibitory response, but whenever the duration of exposure was continued, the biological systems tested would eventually lose resilience and show negative effects from EMF exposure.
EMF protection should improve your heart rate variability over time
Over time, and with consistent use, effective EMF protection devices and methods should improve your overall HRV scores. Many of our customers who own Blushield devices also use an Oura Ring, making it a convenient way of documenting the more subtle effects of using our technology to protect yourself from harmful EMFs.
For those who are curious, we encourage you to keep track of your heart rate variability trends, average resting heart rate, and sleep stats using a health tracking device like the Oura. It’s ideal to get your baseline stats before you begin using a Blushield, and then take note of the changes you see after you start using it. Be sure your personal study duration is of a long enough period – at least a few weeks, or ideally a few months – to reflect accurate trends and rule out other factors.
- Study review: Effects of man-made electromagnetic fields on heart rate variability parameters of general public: a systematic review and meta-analysis of experimental studies – https://www.degruyter.com/document/doi/10.1515/reveh-2022-0191/html?lang=en
- Study: Exposure to cell phones reduces heart rate variability in both normal-weight and obese normotensive medical students – https://www.sciencedirect.com/science/article/abs/pii/S1550830720300872
- Study: Radiofrequency Electromagnetic Field Affects Heart Rate Variability in Rabbits – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8549896/
- Study: The Influence of the Call with a Mobile Phone on Heart Rate Variability Parameters in Healthy Volunteers – https://www.jstage.jst.go.jp/article/indhealth/46/4/46_4_409/_article
- Study: Effect of generated radiofrequency electromagnetic field to heart rate variability in students – https://ieeexplore.ieee.org/document/8242251
- Study: Heart rate variability in workers exposed to medium-frequency electromagnetic fields – https://www.sciencedirect.com/science/article/abs/pii/0165183896000094
- Study: Heart rate variability affected by radiofrequency electromagnetic field in adolescent students – https://pubmed.ncbi.nlm.nih.gov/29469164/
- Study: Heart rate variability in healthy young adults exposed to global system for mobile communication (GSM) 900-MHz radiofrequency signal from mobile phones – https://pubmed.ncbi.nlm.nih.gov/32846174/
- Study: Heart Rate Variability Components in Electromagnetic Hypersensitive Persons – https://link.springer.com/referenceworkentry/10.1007/978-3-319-75479-6_54-1
- Oura Ring: Heart Rate Variability – https://support.ouraring.com/hc/en-us/articles/360025441974-Heart-Rate-Variability
- Oura Ring: What Is Heart Rate Variability (HRV)? – https://ouraring.com/blog/what-is-heart-rate-variability/
- Welltory: Mistakes during the HRV measurement and how to fix them – https://welltory.com/the-12-mistakes-when-measuring-hrv/