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How to use Heart Rate Variability (HRV)

Circular continuously tracks your HRV when you are wearing your ring and automatically draws conclusions for you. These often come out as recommendations on your feed. You can also study your data in the Sleep and Activity circles by reading the graphs and contributors.

Please read our previous article about understanding Heart Rate Variability first.

In this post, you will learn how to take advantage of this amazing metric that is HRV to live your life at its fullest.

Understand your HRV reference

Your HRV reference is your typical HRV as you feel ordinarily. Your reference is the starting point for your HRV explorations since it will help you compare your daily HRV values with a personal long-term value. 

Circular automatically establishes your HRV reference during the 14-day calibration period. Kira is analyzing what your average values are when you feel great as well as how much they fluctuate (standard deviation and coefficient of variation). 

Ideally, you should set your reference during “normal stress” weeks; usual exercise, work, etc is fine during the calibration period. If you establish it during an abnormally stressful or high volume training period then it’s not a big deal because references constantly adjust themselves over time. As your health and fitness levels evolve, it will learn what your new reference patterns are. This happens on a rolling 14-day basis. This value is tailor-made as Kira gets to know how your body works overtime! 

So what do I do once I get my reference? 

Your daily HRV values should be compared to your HRV reference. It is important to understand that your daily HRV must be compared to your own trends and reference because it is unique to you. Don’t compare your daily HRV values to others daily values. 

Sometimes your HRV might lower after a workout and then spike up again. It lowers and spikes up compared to your HRV reference. These trends can unveil interesting messages about how your body is responding to your lifestyle and your environment.

The goal is to get to know yourself and not to compare yourself with others.

Circular also calculates a “Lifetime average”. This is the average of all your daily HRV values since you started using the ring. It is an important measure because it enables you to get the bigger picture. We compare it to your references in order to see the long term trend of your HRV.

Ascending recovery trend with higher daily HRV than Reference

When does Circular calculate my HRV?

Your HRV is tracked continuously during your sleep. It makes more sense to take into consideration your sleep HRV into the analyses as the tracking provides excellent HRV readings in a time window where many of the environmental stressors aren’t present.

How does Circular calculate my HRV?

Circular applies the RMSSD calculation. RMSSD is strongly backed by research and is considered the most relevant and accurate measure of Autonomic Nervous System activity. Root Mean Square of Successive Differences (RMSSD) is the industry standard for calculating HRV.

Where can I view my HRV data and reference?

As mentioned above, your HRV is calculated during your sleep period. You can, therefore, see the detailed graphs of your HRV inside the "Sleep analysis" circle and as it's a contributor of your energy score then you can see your daily value in the contributor the "Activity analysis" circle. 

Circular calculates the average of the measurements to give you one unique value per day. This will be the value that you can compare to your reference.

Analyzing my HRV

Circular makes it easy to understand what are your HRV trends. Every time you wake up you can check your daily HRV value and compare it with your 14-days reference to see where you are at. The interesting parts are when you switch to the 30 day view. It might look like the graph below where you can see clear variations and patterns over several days. That’s where we can interpret the ups and downs and recommend you at best.

In a more micro view, we can even analyze the trend of the curve during the night to detect certain things as good recovery or bad one. Noticeable shapes can be an increasing or decreasing linear line or a v or A shaped curve.

Descending recovery trend even if daily HRV is higher than Reference

You can also receive recommendations on your feed. The recommendations will tell you if anything is out of the ordinary. It will tell you when your HRV is significantly higher than your reference and will tell you if it is significantly low. If it is low we will recommend you to rest or at least take it easy for a few days as you either need recovery from intense exercises / external stress or you are about to get sick.

You can clearly identify the source of an HRV drop yourself, and taking a look at this list might get you on the right path to a higher HRV:

  • Reducing carbs and processed foods/ better diet
  •  Reducing alcohol and smoking
  • Sleep more and follow Circular’s recommendations about your sleep to sleep better
  • Acupuncture/meditation/breathing exercises
  • Exercise  more (aerobics is prefered)
  • Managed stressors
  • Cold therapy with cold showers or sea swims
  • Avoid pollutants and toxins: Avoid canned foods and drink your water out of glass bottles. Stay away from plastic containers as much as possible.

Try using notes about your activities available inside of the calendar to understand their effect on your HRV.

After changing your lifestyle to get a higher HRV, don’t expect your HRV to increase instantly. It usually takes a couple of days, so continue with the good habits a little longer, and see the difference in the graphs for yourself.

As it has been repeated several times, you shouldn’t compare your HRV with others, because HRV is affected by a number of internal and external factors, such as age, hormones and other overall body functions. But as human will always want to compare, here is a table that depicts a picture of average HRV’s depending on your age.

HRV Norms Circular

The most noticeable and common trends

Intensive exercising: You might notice that a very intensive training can acutely lower your HRV, but if you recover well, it will jump back up again soon. This is generally a sign that your body handles the training load well. If your HRV doesn’t jump back up, you may have been training too hard or too often. Overall, regular exercise does tend to increase HRV in the long run, and a high HRV value (compared to your baseline) means that your body should be ready for the next exercise.

Stress / anxiety / bad sleep: If you become stressed or don’t sleep well for a while, you could see your HRV values gradually dropping, indicating that your body might not be at its best, and you need to take some time for recovery.

Getting sick: One interesting finding is that your HRV can jump down if you’re about to get sick even before you develop any symptoms. If this is the case, and you can take it easy for a day or two, your body might fight off the disease. If you get sick, your HRV can stay quite low even after the symptoms are gone. This indicates that your body is still recovering, and isn’t ready for maximal performances.

Alcohol and smoking: Smoking and alcohol consumption reduces HRV. So, you will most probably notice that your HRV goes down momentarily after a night out.

Dehydration: Overall, HRV drops with dehydration but jumps back to its reference level with good hydration. As discussed, both exercise and alcohol can cause dehydration.

Aging: The more you age, the more your average HRV will drop naturally. So it can be very interesting to study your HRV on the bigger picture to see how fast you're getting older.


That’s it! You are only two steps away from improving your wellbeing with CIrcular.

HRV is one of the most interesting metrics for your health tracking. The whole point is for you to understand the effect of your environment on your wellbeing. As weird as it seems, that simple metric is a very powerful tool and can get you very precise insights. Adjusting your HRV is a scientifically proven method and is being more and more used by professionals. Being able to track it from your home at all times might just get you a head start over those who don’t. 

We remind you that the Circular™ ring is not a medical device and should not be used to diagnose or monitor a pathology.

Laurent Bsalis

Laurent is passionate about biohacking and tries his best to be a better version of himself. He also eats too much ice cream which is a problem.

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