If someone was to ask you “hey, how healthy are you?” How do you answer this question? You might say “well, you know, I exercise regularly, eat well, I don’t drink, etc. etc.” Or you might pull out your smartphone and flaunt your daily steps statistics and average heart rate. But are these really true indicators of your overall health status? Well, not really. But surely, in the age of driverless cars, robots playing basketball and performing open-heart surgery, we can find a way to quantify our overall health without ambiguity. Well there is, and it’s called Heart Rate Variability, or HRV.

A New Gold Standard In Health Analysis

A Harvard article referred to HRV as “a new way to track well-being.” But what is heart rate variability? Essentially, it’s showing how each unique individual responds to physical and physiological stressors that occur throughout the day. Everything from exercise, diet, sleep, medication, stress and anxiety can have great impact that can truly be measured. It’s like an MRI machine for stress. Your body’s true performance indicator; much like vehicles have a check engine light, heart rate variability is like a check engine light for your overall health. It is a true test of ones autonomic nervous system (ANS) function. This is the part of your nervous system that controls actions that you can’t consciously control, like digestion, kidney function, heart rate, sweat and respiratory rate. Meaning you won’t physically feel if something is off. 

Let’s take diet for example; it’s for certain that individuals have different responses to the same food. So if you eat a burger, and someone else eats that same burger, your bodies will have different reactions. It’s possible that the impact of you eating that burger is a negative one. However, you wouldn’t even feel it. If your body doesn’t agree with certain foods, your brain will trigger a stress response. The only way we can capture this response is by using heart rate variability. So by measuring HRV before and after you eat, you can see if it improves or worsens after particular foods were ingested and eliminate them from your diet. You can remove foods from your diet that trigger a negative reaction to optimize your diet. Ok, maybe not completely eliminate, but at least don’t consume as often.

So How Does Heart Rate Variability work?

From a technical standpoint, HRV is measuring the time difference (in milliseconds) between each successive heartbeat. Naturally, our heartbeats vary beat-to-beat, and HRV captures this difference. Generally, the more sporadic your heart beats, the healthier the individual. If your heart beats like a metronome, it could mean serious internal health issues. 

Now the question is, how do we extract HRV? Now this is very important. If the data is not properly and accurately extracted, it will lead to an inaccurate depiction of ones health thus complicating the decision making process. Some fitness trackers claim they can monitor individuals HRV, but this is far from the truth

Dirty little secret: Almost all fitness trackers today have an integrated optical sensor in the hardware. This is the sensor that captures beats per minute (BPM), which has become a standard function among today’s wearable devices. These sensors typically capture 25-40 samples per second. Meaning before you see your BPM result on your smart watch or fitness bracelet, the sensors reads your heart rate 25-40 times before appearing on the screen. The way the algorithms of these apps work is that sensors will record 1 second of your heart rate and multiply by 60 to get you your BPM. Maybe this wasn’t the juicy secret you were hoping for, but many people don’t know this stuff! 

While this type of data gathering might be okay for BPM, it surely won’t work for capturing heart rate variability. We need a wearable device with a higher sample rate, though some products like Whoop and Athos claim their sample rate is 50 samples per seconds, slightly higher than the industry average. Regardless, there is one tool available that can give us that high sample rate. 


Electrocardiogram(ECG / EKG) is what we’re looking for. If you’ve ever been hooked up to an ECG machine, you know it can be a bit of an ordeal. But with the advent of new wearable technology, ECG monitoring has become much simpler to do from home. Just in the past couple of years we’ve seen several ECG monitors become available on the market given the increased demand for such products; Products like the Vitascout by Vivalink, QardioCore by Qardio and the AIO Smart Sleeve by Komodo Technologies. 

The sample rate of ECG wearable devices usually ranges anywhere from 250 – 1000 samples per seconds. That’s up to 25 times more samples per second than the standard optical sensor like those used in Fitbit and Garmin products. You might be thinking, what difference does the sample rate make? When we talk about heart rate variability, remember, we’re looking at infinitesimal changes between each heartbeat. A higher sample rate, means better accuracy. So using ECG to extract HRV as opposed to using an optical (BPM) sensor will actually create a much more accurate picture. 

HRV Scoring

So how do you read HRV? Typically this is a score out of 100 points. The higher the HRV, the healthier you are. Though some companies have put their own spin on this score because it could be confusing to some. Some products simply show you a “good” or “bad” or “neutral” result. Other products like the AIO Smart Sleeve show a score based on the 5-star system, which they call Health Score™.

Why use Heart Rate Variability

Although there are many fitness trackers and health monitors on the market nowadays, we need to be careful and differentiate the motivational devices vs. devices that capture meaningful health data. Products whose main feature is steps or BPM fall into the motivational device category. Step counting continues to be the top reason people buy particular devices. But step counting doesn’t really tell us anything about our health.

If I take 10,000 steps a day for a year, surely I’m doing something right. But what if I also consume a Big Mac meal every day that year as well?  That can’t be good, but steps alone obviously wouldn’t capture additional factors. This is not to say these devices are crap. Far from it! Motivation is a powerful tool, and if these devices motivate people to be active, that’s an amazing accomplishment and more people should have these devices. However, to truly get to know your own health and how your body reacts to its environment, you need other tools to help you achieve a healthier lifestyle. 

The reason steps counting is so widely used by consumers is because it’s easy to understand and implement. Just walk, right? Whereas HRV is more complex and really gives power to the individual to monitor every day and make changes to their every day life. Once you learn how to implement it and use as intended, it can have tremendous benefits to your health and is a game changer. So how to use it properly?

1. Heart Rate Variability and your diet

As mentioned before in the example with the burger, every individual has a unique reaction to different foods even though they aren’t consciously aware. You should check you HRV before and after meals to see how that food affects your body. And it could be different day-to-day depending on how much stress you’ve put your body through that day. So if you eat the same foods every day, and you notice that on Wednesday your HRV dipped significantly after a meal, you should analyze what you did that day and why your body reacted differently. Perhaps you had a fight with a friend, got called in to HR at work or broke up with a significant other. Yes, these things can all contribute to high stress that will inevitably affect everything else you do that day

2. Heart Rate Variability and exercise 

Lots of professional sports teams use HRV as a tool to optimize player performance and recovery. But you don’t need to be a pro to use it. You can use it if you’re doing cross fit, yoga, cycling, even walking your dog and doing lawn work. It’s truly a universal tool. When you exercise, your HRV will automatically decrease. This is because working puts your body under a great amount of stress. But that’s ok. This is good stress. However, if that stress from the workout follows you all day long, that’s not good.

HRV is used to gauge how well one recovers from stress, in this case, it’s exercise. If you are fully recovered and your HRV is back to it’s baseline within 1-2 hours, that’s good! It’s a sign of a healthy functioning body that recovers quickly from training. If your HRV stays the same and doesn’t change for hours upon hours, that’s not a good sign. Maybe you went to hard at the gym or on your bike ride. But with HRV, this could have easily been avoided.

Are You Ready?

Another way we use heart rate variability with activity is readiness. If you know you HRV baseline, or your average, and you notice it’s much lower before heading out on your run, you might want to think twice. Exercising and straining your body when HRV is below it’s average definitely does more harm than good. Could be a sign to take the day off or just do light activates. If HRV is well above your average, you’re good to go! But remember, constantly straining your body when you see a low HRV will not only negatively affect a single day, but could ruin an entire week if it becomes a pattern. Again, HRV gives you control over your own body, and destiny. Cool, right?

3. Heart Rate Variability and Sleep? 

Ok, so yes, many fitness trackers already come with sleep monitoring that you can view on an app. But it’s only tracking how you move at night to determine whether you are in deep sleep or not. While this is good, it doesn’t give us a complete picture. I mean what good is the Mona Lisa without her head, right? 

Measuring HRV before bed and when you wake up gives us true indication of sleep quality and whether one is fully recovered from the day before. If some days are better than others, pay attention to what it is your doing on good sleep days vs. bad ones. Notice your nighttime routine. Are you on your phone a lot? Did you eat before bed? Did you consume alcohol? See what happens to HRV in the morning if you don’t do these things and optimize your sleep.

4. HRV and Stress

Perhaps the most researched topic with respect to heart rate variability is stress and anxiety. Over and over again, clinical research shows a direct correlation between HRV and mental stress. Of course you can’t prevent stress completely, but having visual representation of your stress level is huge. You can identify exactly what things in your life are causing stress and you can look to improve in those moments. Surely you’ve heard people say, “just take a deep breath” when in a tense situation to urge one to calm down. Well, there’s real science behind it. 

Deep breathing exercises have been shown to greatly increase heart rate variability, and thus reducing stress. In a case study conducted using the AIO Smart Sleeve, 50 users measured their HRV before a stressful situation and after, while doing deep breathing. There was an average of 2.2 rise in HRV (out of 5 stars), which is quite significant. 

Warning: do not attempt breathing under water

The Ice Man

Maybe some of you are familiar with Wim Hof, creator of the Wim Hof breathing method. He is well known for immersing himself into ice baths for a record amount of time, and swimming under a sheet of ice in the arctic while only wearing goggles and a pair of trunksHow can he do that? When your body is exposed to that level of cold, your autonomic nervous system (ANS) is fighting like crazy to stay in balance. Deep breathing counteracts the negative affects on your ANS. Now not everyone can do this. But Hof has such exceptional control of his breathing that it almost completely wipes out the stressors that occur from being under such cold temperatures.


Although it’s not a widely used biomarker at this point in time, one thing is for certain; many researchers and clinical studies validate the use of HRV for every day living. According to World Health Organization (WHO)stress if the health epidemic of the 21st century, and heart rate variability might be the only tool that give us insight into the stress and mental health of an individual. While it’s maybe a couple years away from becoming the gold standard for health assessment, there’s still ways to use it now to improve your life. 

In our next blogs we will bring up all the amazing research and show you how you can use it to improve your health.


  1. Agree this is a great tool. I’ve been using since they were made available on the market, brands like AliveCor and Qardio…. tough to use at first but as you learn and wearables become better, definitely worth it whether your active or not

  2. I recently started tracking my heart rate variability and it has helped in my training no end. In the past I would have ‘manned -up’ and just pushed through being tired and then most likely injured myself now using HRV I can back off and know when I’m actually overtraining and get a much better performance over time! Highly recommend fitness enthusiasts follow this approach

  3. HRV application is not only for training and exercise. There’s so many more uses and applications to every day life like diet and stress. People really need to know these things

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