Circular Ring: Help

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Best practices from a high-performance coach and bio-hacker: Siim Land


Waking up sounds the beginning of the day and you know the importance of a good wake up. You even wrote an e-book called “Waking up Empowered”. Why do you believe it to be so important?

“The way you wake up determines how the rest of the day is going to go. If you start ruminating over negative thoughts or hit the snooze, then you’re telling your brain what kind of a rhythm to follow. On the other hand, if you get up doing something productive such as meditation or making your bed, you’re dragging momentum to your side and everything else gets easier as well.

There’s a reason people use the idiom of stepping out of bed with the wrong foot. Your brain is plastic and always listening to the feedback it receives from your thoughts, emotions, and actions. That’s why I believe in getting quick wins as soon as possible. It can be taking a cold shower, reading a few pages, writing a journal or exercise. Whatever puts you into the flow of things. In any case, train your brain to avoid negativity and procrastination.”

What would be your top tips for a better wake up? How do you personally combat sleep inertia?

“The best tip for a restful wake-up is to wake up naturally without an alarm clock. This way your brain will gradually pull you out of sleep at the lightest stage of sleep and at the end of a sleep cycle. Sleep inertia happens when you get shooked from a deep sleep in the middle of it.

Ideally, you want to not use an alarm clock and stick to a consistent bedtime so your body could develop the habit of waking you up around the same time. If this is not possible, then using specific smart alarm clock or circadian alarm clocks that start calibrating light towards more brightness to mimic the sunrise is also useful.”

What does your routine look like right after waking up?

“After getting clothed I make my bed and go outside to get some fresh air and daylight. This will kickstart the proper circadian rhythm. I may also do some breathing exercises and stretches to get the blood flowing. Then I go inside and start working on my laptop until noon.”


Do you have any sleep hygiene tips that are easily implemented?

“Use blue-blocking glasses to filter out artificial light in the evening. This protects your circadian rhythms and enables the body to produce melatonin the sleep hormone.”

Can you explain the relationship between sleep on activity and better performances?

“Sleep facilitates recovery and adaptation. Without enough sleep, your body wouldn’t be able to repair itself from both cognitive and physical activities. Poor sleep also decreases reaction time, alertness and mood.”

You also talk about sleep and fat loss. How is that directly affected?

“Sleep improves the body’s metabolic flexibility and insulin sensitivity. Sleep deprivation raises blood sugar and cortisol the stress hormone, which makes it easier to get diabetes and gain weight. Psychologically, short sleep also makes you want to eat more food and you’re less satisfied with it.”

Serotonin and thus Melatonin impact our Circadian rhythms and finding the perfect sleep balance is key for a good night’s sleep and to improve our energy. How can one boost his melatonin/serotonin secretion?

“Light exposure affects melatonin the most. That’s why blue blockers and dimming down the lights in the evening are crucial. Certain foods with some carbs and protein will also promote serotonin, which leads to the creation of melatonin. The best foods for that tend to be poultry, meat, bananas, rice, and cherries.”

We’d then be tempted to take melatonin (or other) supplements. Is it a solution in on the long run? Are there natural supplements out there that offer a better alternative?

“Taking supplements is a quick-fix that doesn’t address the underlying cause. It should be used only in some cases like jet lag or poor sleep and not as a staple. Instead, you should focus more on the light environment, food intake and stress management.”

What would be your main takeaways and pieces of advice for better sleep? Are they any gadgets, products or hacks you can recommend?

“In my own experience, filtering out bright lights in the evening is the most effective strategy for getting better sleep. This way you’ll naturally get sleepier. Tracking your sleep with gadgets will also give you more insight into how well you sleep.”


With everything that is said above, we might get conflicting information about which diet to carry out. With your experience and personal findings, what have you found to be the best diet?

“The optimal diet depends on the person’s energy requirements, genetics, lifestyle, and preference. Generally, anything that helps you to lose weight and stay lean will improve your health and sleep better. Overeating even healthy food isn’t a good idea but whole foods that are minimally processed tend to be the healthiest. Most people also undereat protein, which is the most important macronutrient for improving body composition. Hyperpalatable foods that combine fats and carbs together are low in protein, which is why you tend to overeat them. Higher fiber intake will also create more satiety while keeping the overall calories low. Carbs should be calibrated based on exercise intensity and activity levels.

Skipping meals and doing some intermittent fasting has been shown to be effective for improving body composition but it also has many longevity and anti-aging benefits. That’s why I eat only 1-2 times a day and avoid snacking.”

What are the main reasons for trying to stick to such a diet?

“A high satiety diet that helps you to improve your body composition will make your body more metabolically flexible and helps to stay healthy in the modern food environment.”

Have you found any negative impacts of such eating habits? What about positive impacts?

“More energy, easier to stay lean and having more muscle makes my body burn more calories at rest.”

Would you have any advice for anyone trying to start implementing such diets?

“Focus on nutrient density and not calorie density. Chew your food properly in a low-stress environment to avoid overeating.”

To go further with biohacking

If you wish to learn more about how to master your body, develop your mind, build muscle, lose fat, get motivated, achieve your goals, get more energy and increase productivity, check out Siim’s youtube channel here. Don’t hesitate to also follow him on his socials: Facebook, Twitter and Instagram.

You can also check out his website here with an incredibly vast amount of resources with blog posts, podcasts, e-books and much more.

Sleep disorders classification


Insomnia is characterized by a difficulty of falling asleep, frequent or prolonged nocturnal awakenings, or finally prematurely waking up with an inability to sleep again.

Basically, taking more than 30 minutes in average to fall asleep, or spending more than 30 minutes awake in the middle of the night, with a sleep duration of less than 6.5 hours per night represents a problem of insomnia. If you have difficulty staying asleep or falling asleep at least three times a week, you probably have insomnia.

There are different possibilities of cause:

  • Temporary insomnia
  • Poor sleep hygiene
  • Psychophysiological insomnia
  • Bad perception of sleep
  • Insomnia related to a mental disorder
  • Insomnia related to a medical condition
  • Insomnia due to a drug or substance


Hypersomnia is characterized by a difficulty of staying awake and an important need to sleep (sleeping too much, too often, and / or at anytime) when it’s not associated with circadian rhythm disorder, respiratory disorder or any other cause of sleep disorder.


Narcolepsy is a neurological disorder that affects the control of sleep and wakefulness. People with narcolepsy experience excessive daytime sleepiness and intermittent, uncontrollable episodes of falling asleep during the daytime. These sudden sleep attacks may occur during any type of activity at any time of the day. 

The difference with Hypersomnia lies in the fact that Hypersomnia leads to sleeping excessive amounts of time and having severe difficulty waking up after sleeping (i.e. excessive sleep inertia). People with narcolepsy frequently do not sleep excessive amounts of time, and may find brief naps refreshing. Many people with narcolepsy also experience symptoms related to REM sleep instability such as sleep paralysis.

Sleep disorders related to breathing

We know that not only is the amount of sleep important, but also its quality.

A night breathing issue causes poor sleep quality with frequent nocturnal awakenings (conscious or unconscious). There is two main category of night breathing disorder. 

Obstructive sleep apnea

The most common one is the obstructive sleep apnea. It results from obstruction (partial or complete closure) of the breathing airways. The body makes an important effort to breathe, but the air does not pass. About 9 out of 10 people who experience apnea have obstructive sleep apnea. Often these people snore.

Central sleep apnea

During a central sleep apnea, no effort to breathe is manifested and no volume of air passes through the lungs: the breath is simply no longer. Central apnea is often accompanied by obstructive sleep apnea. “Pure” central apnea is quite rare. Medical problems such as heart failure, stroke, and kidney failure can cause this central sleep apnea syndrome. It can also be caused by chronic intake of medication and drugs such as opioids, especially methadone, hydrocodone and morphine.

Circadian rhythm disorders

Circadian rhythm disorders are characterized by a disruption of the biological clock.

Delayed Sleep Phase Disorder (DSPD)

People with DSPD generally fall asleep some hours after midnight and have trouble waking up in the morning. We are not talking about a deregulation due to lifestyle but about a genetic cause. The syndrome affects 0.5% of the world’s population. If they are allowed to follow their own schedules, e.g. sleeping from 4:00 am to 1:00 pm, their sleep is improved. Attempting to force oneself onto daytime society’s schedule with DSPD has been compared to constantly living with jet lag. An adolescent version may disappear in late adolescence or early adulthood; otherwise, DSPD is a lifelong condition. 

Advanced Sleep Phase Disorder (ASPD)

It is a condition in which patients feel very sleepy and go to bed early in the evening (e.g. 6: 00-8:00 p.m.) and wake up very early in the morning (e.g. around 3:00 a.m.). The syndrome affects 1% of the world’s population.

Irregular Sleep-Wake Rhythm

The irregular sleep-wake rhythm is one of the rarest circadian rhythm disorders. Sleep is divided into three or more short-term episodes of sleep, distributed day and night. A fundamental impairment of the biological clock is suspected. The number of hours of sleep acquired in 24 hours is often equal to that of people who have normal sleep patterns however they are suffering from a lack of deep sleep, which is necessary for the body’s natural regenerative process.

Non-24-Hour Sleep-Wake Disorder

If you have Non-24-hour sleep-wake disorder, you may find yourself gradually going to bed later every night and waking up later each day. It is very rare, and it occurs because the internal clock is not sync with the day and night cycles. Most individuals with this disorder are blind people. But sometimes people who have normal vision can suffer from it.

Muscular issues during sleep

Muscular issues during sleep are benign motor disorders. Sometimes it can be dangerous  because of the external environment around the individual. But most often, these movements are without consequences.

REM Sleep Behavior Disorder

While being asleep, the person begins to mimic his/her nightmare/dream and suddenly begins to speak, shout, gesticulate abruptly. These dreams often have a part of violence, and there is a concordance between what the person dreams and what he/she does.

Periodic Limb Movement Disorder

It is characterized by rhythmic movements of the limbs during sleep. The movements typically involve the legs. Movements occur periodically throughout the night and can fluctuate in severity from one night to the next. These movements are very different from the normal spasms, called hypnic myoclonia, that we often experience initially while trying to fall asleep. It can often cause a partial or full brief awakening, resulting in fragmented sleep. Patients are frequently unaware of these movements.


Sleepwalking is manifested in complex and automatic behaviors, including strolling out of bed, during deep sleep.

Nocturnal cramps

Nocturnal cramps are muscle contractions that affect a muscle or a muscle group. They are usually located on the legs, a calf or a foot. The cramps are very painful and they appear spontaneously and involuntarily. They are usually short and can be repeated several times during the night.

Nocturnal Bruxism 

If you get up in the morning with pain in the jaw muscles or with headaches, you may be suffering from bruxism. Bruxism (grinding and clenching of teeth) is a common behavior; reports of prevalence range from 8% to 31% in the general population. Bruxism can cause dental pain and / or make teeth loose; sometimes even pieces of teeth can come off (fracture). Over time, bruxism can destroy bone and soft tissues surrounding teeth.

Sleep paralysis

Sleep paralysis is a state where a person is aware of his incapacity to move despite his desire to do so. It manifests itself when the person is falling asleep or waking up. This can be accompanied by a hypnagogic hallucination.

Psychological issues during sleep


Hypnagogic hallucinations are intense and impressive hallucination that occur at the beginning or end of a sleep period. All the senses can be affected, or only some of them. It is often difficult to distinguish between hallucination and reality. Hypnagogic hallucinations are often represented by something scary.

Confusional arousals

Confusional arousals is an episode of confusional state occurring during or after awakening. The person is disoriented in time and space, is slowed down (slowness of ideas, difficulties of speech, difficulties of understanding …). The person can make incoherent remarks, sometimes related to a dream. His behavior may be inappropriate, inconsistent, or even violent.These episodes can be repeated several times a night. They occur most often during the first hours of sleep, and after a nap. There is always a complete or almost complete amnesia of the episode.

Nocturnal emission

A nocturnal emission, informally known as a wet dream or sex dream, is a spontaneous orgasm during sleep that includes ejaculation for a male, or vaginal wetness or an orgasm (or both) for a female. These emission are often associated with erotic dreams.

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

How much sleep should I get? Sleep demystified. Basics n°5 about sleep

Sleep needs vary across ages and are especially impacted by lifestyle and health. To determine how much sleep you need, it’s important to examine what factors of your own lifestyle are affecting the quality and quantity of your sleep then assessing how you respond to different amounts of sleep. Of course, the quality of your sleep will also impact how much time you need.

But let’s say your sleep quality is good, the National Sleep Foundation assess an adult sleep duration to be between 7 to 9 hours. There is a good chance that it suits you by looking at the distribution diagram below.

Average Sleep Duration Circular

But as you see on the graph it won’t suit everybody since there are exceptions.

The best way to find naturally your sleep need is to assess how you respond to different sleep duration. Do the test without having done sports activity the day preceding. See how you respond to that. If you feel tired, you add another cycle duration to the next night. On the contrary, remove one if you feel good. Once you have found the sleep duration that suits you in normal condition, we advise you to add a cycle on the days of sports activity to help your body restore better.

The easy way is to use the Circular ring. The ring will detect automatically your sleep cycle length, assess how you respond to your current sleep schedule by analyzing several parameters that reflect your energy such as your heart rate variability, your sleep quality, your time to fall asleep, your activity, etc… and recommend you the perfect time you need to sleep. 

Oxygen Saturation (SpO2) and how to use it to your advantage

Only recently, have these readings been available from the comfort of our homes with the advent of small and precise sensors. Anybody can benefit from a preventive tracking of respiratory problems thanks to Circular and checking your blood oxygenation might just help you with that. 

Blood Oxygen Circular

How does it work?

When oxygen is inhaled into the lungs it attaches to a protein in red blood cells called hemoglobin. The red blood cells transport the oxygen into the bloodstream and flow through pulmonary veins, then into the left atrium and left ventricle, and finally circulates throughout the body’s organs and their cells. 

To know how much oxygen is in your blood, the sensor at the bottom of your ring emits red and infrared light. While passing through your finger, the light hits your blood cells, and is absorbed differently by the hemoglobin without oxygen (deoxyhemoglobin) than by the hemoglobin with oxygen (oxyhemoglobin) because of their concentration and resistance to light. The calculated rate is expressed as a percentage and a normal reading ranges from 94 percent to 100 percent.

Circular’s readings are accurate and provide results within a 2-percent difference either way of what it truly is. If your reading was 90 percent, your true oxygen saturation level may be anywhere between 88 and 92 percent. You should also keep in mind that external factors such as movement and temperature can impact the accuracy and that you should always consider your baseline and personal feeling as a primary assessment. Use your blood saturation as a tool.

We will first discuss how to interpret your readings for your wellness, and then discuss how it might help you.

Spo2 for health and prevention

Pulse oximetry is a method doctors use for rapid assessment and monitoring of a patient’s respiratory function. It may be used to monitor the health of individuals with any type of condition that can affect blood oxygen levels, especially while they’re in the hospital. But let’s leave this work to the doctors.

SpO2 for Sleep Apnea Evaluation 

You might correlate blood oxygenation to sleep apnea events (sleep disorder in which breathing repeatedly stops and starts). The good news is that it can be a great indicator and reflects these events well. 

There is around a twenty-second delay after the onset of the cessation of nasal airflow. The measurement of SpO2 level is useful for screening suspected sleep apnea events, but it might not be able to provide live and precise occurrences. It is a way to better understand sleep, not to necessarily diagnose sleep conditions. Best practice would be to check your readings in the mornings by keeping in mind these simple facts: Less than 5 sleep apnea events an hour is considered normal. You might want to check with your doctor if that exceeds 15. Look for sudden drops in the graph. 

Associated symptoms may be: frequent morning headaches, swelling in ankles and feet (edema), tiredness, shortness of breath, irregular heartbeats rhythms, high blood pressure,

lightheadedness, dizziness, skin and nail beds may turn bluish in color (cyanosis), confusion, memory loss, higher red blood cell count in blood (polycythemia).

SpO2 for Recovery

Oxygen saturation is a key factor in performance if you live or train at altitude, or tend to overtrain. Using SpO2 readings with your usual training metrics can, first and foremost, help you gauge whether you’re recovering properly.

An athlete that wakes up feeling “not right” after a hard training block and a poor night of sleep will tend to see his SpO2 reading lower than is baseline SpO2. This is a great case of an athlete who may feel well enough to go train, but his low sleep hours and low SpO2 corroborate his sense of “not feeling right.” Instead of continuing his training as planned, this athlete should focus on recovery and sleep more for the next days. Subsequently his SpO2 will normalize and the following training days should go very well.

Correlate your RHR, HRV and SpO2 after training days to see where your recovery is. Paying attention to the right numbers can result in a good training block and even help avoid an over-training.

SpO2 for Altitude Acclimatization

At altitude, where the air is thinner, it is more difficult for your body to get adequate oxygen to your muscles and tissues. For example, if you’re racing or training at 10,000 feet (3000 m), the amount of effective oxygen in the air is about 15 percent (compared to 21 percent at sea level). If you’re used to living at sea level, this change in oxygen availability will kick off a cascade of physiological adaptations, some of which are advantageous no matter where you’re racing.

To start, there will be an increase in your respiratory and heart rates; and the volume of blood ejected from the heart (stroke volume) will be reduced. Over your first 24-48 hours at altitude, blood plasma volume will also be reduced to improve the oxygen-carrying capacity of your blood by volume. These adaptations won’t necessarily feel good, in fact you’ll probably feel like you’re doing more work for less reward.

In the first couple of days at altitude you want to see a lower SpO2 and an elevated heart rate (HR) and respiratory rate (RR). This is your body attempting to balance out the lack of oxygen in the air by moving it faster through your body.

With prolonged stays at altitude, most people’s SpO2 will stay about the same or increase slightly; but your heart and respiratory rates should normalize, as well as your ability to perform an exercise at altitude. A SpO2 of 88 to 92 percent will give you the most beneficial training adaptations without causing undue fatigue.

That means you’ll be able to race and train as normal at altitude, and will likely enjoy some extra endurance at sea level.

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

Scientific sources:

How does Circular track my Resting Heart Rate (RHR) and how to use it?

Resting Heart Rate can help you get an idea of your overall wellness and fitness, and can help you set fitness goals.

The fitter you are, generally the lower the Resting Heart Rate. This is due to the heart getting bigger and stronger with exercise, and getting more efficient at pumping blood around the body, so at rest, more blood can be pumped around with each beat, therefore fewer beats per minute are required. 

Usually, the best moment to measure RHR is just after waking up but we can’t force you not to be active after waking up. So we find that the best measure is taken when getting in your bed before going asleep. We give one average reading per day inside the “Activity analysis” circle.

Circular takes a measure of your Resting Heart Rate when resting, although not sleeping (as your heartbeat significantly drops then).

Your own baseline RHR

A RHR between 60 and 100 beats per minute (BPM) is considered normal, but 60 to 80 is optimal. Generally, a lower resting heart rate indicates more efficient heart function and greater cardiovascular health. Research has connected a higher Resting HR with a higher risk of cardiac events like stroke and heart attack.

Many factors influence what’s normal for any one person. Genetics, age, and gender all have an impact on your baseline HR and play a part in determining your normal range. Those aren’t really things that you can change, but there’s one factor you can: your fitness level.

Circular automatically determines your baseline RHR for you. You are able to find it in the “Activity analysis” circle, by swiping to the RHR graphs. It is represented as a blue line for comparison. As your fitness levels are what can impact the most efficiently your RHR for the better, Kira is made to recommend certain activity programs or lifestyle changes for you.

Average Resting Heart Rate Circular

What can be deduced from RHR:

You’re not active enough

If you’re sedentary most of the day, your RHR likely approaches or exceeds the top end of the range above. This may be because your heart is less efficient. The good news? By regularly engaging in moderate to vigorous aerobic activities (brisk walking, biking, swimming), you will help your heart become more efficient at pumping blood which will lower your Resting Heart Rate over time. Even modest reductions in RHR can dramatically reduce your risk of cardiovascular disease and add years to your life!

You’re overtraining

While pushing your body can lead to great gains, it can also be detrimental. If you notice an increase in your Resting Heart Rate when you’re going heavy on the training and light on the rest, your body may be telling you that you need to scale back. By giving it the proper rest it needs, your body can repair and adapt and you may bounce back stronger than ever.

You’re too stressed

Prolonged mental and emotional stress can also cause your RHR to creep up over time. Try adding relaxation into your day: read, meditate, go for a walk with friends. Regular relaxation activities may help you combat your stress and which could lead to a lower RHR.

You’re sleep-deprived

Always exhausted? Chronic sleep deprivation which can lead to fatigue, a slower metabolism, and extra snacking can also raise your RHR. Aim for at least 7-9 hours of sleep each night.

You’re dehydrated

During a hot summer day, if you notice a temporary increase in your RHR, your body might simply be trying to cool down. However, it could also mean you’re dehydrated especially if you’re thirstier than usual, your mouth is dry, and your pee is more yellow than normal. To help lower your RHR, drink more water.

You’re developing a medical condition

If you experience shortness of breath, unusual fatigue, dizziness, and your RHR has increased, you might be at risk for a medical condition. High RHR can be a sign that something is abnormal. However, even if you have a low RHR combined with symptoms (like those above), it could indicate an issue.

Don’t just look at the RHR, combines it with all the metrics especially HRV. If your RHR looks unusual but you don’t feel lightheaded, weak, short of breath, dizzy, then there is nothing to worry.

Resting Heart Rate increases with age
Most of the time your RHR can be modified. Unfortunately, as you get older, your RHR tends to increase. To reduce the impact that aging can have on your cardiovascular system, you can help maximize your results by exercising within your target HR zone to help lower your RHR. You can compare to other people your sex and age to get a good idea if you’re in the averages. But keep in mind an average isn’t personal (genetics too are involved!) and doesn’t necessarily reflect the best practices and target RHR. We recommend you to stick with Circular’s recommendations.

Medication affects Resting Heart Rate
Changes in your RHR can also result from over-the-counter or prescription medications. Medications to treat asthma, depression, obesity, and attention deficit disorder tend to increase your RHR. However, medications prescribed for hypertension and heart conditions (beta blockers, calcium channel blockers) typically decrease your resting heart rate.


Circular will send you recommendations concerning your wellness if it detects something abnormal. Never forget to never just look at the numbers, but also evaluate how you feel for yourself.

The RHR is a very good tool to correlate with your HRV, your sleep and, your activity. If the HRV and RHR indicators are relevant together then you can consider analyzing your vital signs over the next few days.

Although, when thinking solely about your wellness, RHR is a great tool and the programs designed in the programs circle might help you out. Don’t forget to also follow Kira’s recommendations about your sleep schedule. You will always have a great companion by your side in your Circular app (Kira), that’ll try to do its best at helping you higher you RHR in good proportions. And remember that her recommendations are measured and have a good chance of reflecting situations you’ll be better off changing.

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

In practice 

In your Circular app, dive into the activity analysis circle. On the first page is displayed, along with other metrics, your daily RHR measure. As stated previously, there is one measurement a day.

Resting Heart Rate Circular

How to use Heart Rate Variability (HRV) with Circular?

Understand your HRV baseline 

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

During the first weeks, the app is establishing your baseline. It is looking to see what your average HRV values are as well as how much they fluctuate (standard deviation and coefficient of variation). 

Ideally, you’ll form your baseline during a “normal stress” week. Exercise, work, etc is fine during this first week. If you establish it during an abnormally stressful or high volume training week then it’s not a big deal because the baseline constantly adjusts and updates itself over time, so as your health or fitness levels change, it will learn what your new baseline 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! It is important to understand that HRV is an interesting metric to compare to your own trends and baseline because it is unique to you.

So what’s the big deal with HRV baseline? 

Well, it is used as a comparison to your HRV trends over time. Sometimes your HRV might lower after a workout and then spike up again after a couple of hours. It lowers and spikes up compared to your baseline HRV. These trends can unveil interesting messages your body is sending, that is why in the app’s graph, you will always find your baseline HRV as a comparison to your daily/monthly/lifetime HRV graphs. 

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

Circular also calculates a “Lifetime Baseline”. It might get tricky to understand, but in practice, it is made easy to comprehend. This measure is the average of all the baselines calculated each week, your average baseline 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 weekly calculated baseline in order to see if you’ve lowered your HRV or not over time.

When does Circular calculate my HRV?

Your HRV is tracked only during your sleep. It makes more sense as nocturnal tracking provides an excellent HRV measurement window where many of the environmental stressors aren’t present.

The time when you sleep is also the period when your body is at rest. Is also makes sense because HRV is the indicator for rest-related parasympathetic autonomic nervous system. That is why you will find the details in the sleep analysis section of the app.

Circular Heart Rate variability at Night

How does Circular calculate my HRV?

We apply the RMSSD calculation. RMSSD is strongly backed by research and is considered the most relevant and accurate measure of Autonomic Nervous System activity over the short-term (5 minutes or less). Root Mean Square of Successive Differences (RMSSD) is the industry standard for calculating HRV.

Where can I view my HRV data and baseline?

As mentioned above we take the values of your HRV during your night. You can, therefore, see the details of your nights data inside the “Sleep analysis” circle. Then we calculate the average of these values to give you one unique value per day. This will be the value that you can compare to your baseline. You can find it in the “Activity analysis” circle as well as in the “Sleep analysis” circle.

The interesting parts are when you switch to the -weekly- or -monthly- view. It might look more 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.

Circular Heart Rate Variability

Comparing my HRV with my baseline

Circular makes it easy to understand what are your HRV trends. Every morning you can check your daily HRV value and compare it with your 14-days baseline to see where you are at. You can compare your values by visualizing the whole week, to know its evolution and compare each day between them. And you can also compare your data in a wider view; by month and by lifetime, where your monthly average can be compared to your lifetime baseline. This can allow you to see if you have succeeded in increasing your baseline over time.

You can also receive recommendations on your feed. It will tell you if you are ready for the upcoming day if your HRV is largely higher than you baseline HRV and will tell you if you are not ready if it is largely lower than you baseline HRV. If it is lower and you receive such a recommendation in your feed we will recommend you to rest or at least take it easy for few days as you either need recovery from intense exercises or you are stressed or about to get sick.

If you clearly identify the source of an HRV drop yourself, there are no mysteries and taking a look at this list of things to do might get you on the right path to a higher HRV:

  • Reducing carbs and processed foods/ better diet
  •  Reducing alcohol quantity
  • Sleep  more or follow Circular’s recommendations about your sleep
  • Acupuncture/meditation/breathing exercises/listen to music  (HRV increase for a day or two afterward)
  • Exercise  more (aerobics is preferred)
  • Managed stressors  with acting & improv classes
  • Cold therapy with cold showers & sea swims
  • Avoid pollutants and toxins: Avoid canned foods (the linings contain BPA) and drink your water out of glass bottles or containers. Stay away from plastic containers as much as possible.

Noticeable trends might be:

  • It is interesting to note that your HRV can fall down if you are about to become ill before you even develop symptoms. If this is the case, and you can take it easy for a day or two, your body will fight the illness. Your HRV can stay very low even after the symptoms disappear. This indicates that your body is still recovering and is not ready for maximum performance.
  • You may notice that a very intensive exercise can significantly reduce your HRV, but if you recover well, it will come back to your baseline and above. This is usually a sign that your body is coping well with the training load. If your HRV does not rise back, you may have trained too hard or too often. However regular endurance exercises tend to increase your baseline HRV over the long term.
  • If you do not sleep well or become stressed, you may see your baseline HRV decreases, indicating that your energy may not be at its best and that you need to take some time to recover.
  • Smoking and alcohol consumption can reduce your baseline HRV.
  • You will most likely notice that your HRV drops down temporarily after a night out.
  • Overall, HRV decreases with dehydration and returns to baseline with good hydration. As mentioned, both exercise and alcohol can cause dehydration.

After changing your lifestyle to get a lower HRV, don’t expect it to get back to its baseline 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.

That’s it! You are only two steps away from improving your lifestyle with CIrcular, in ways you never could of before with such precision and ease.

Indeed, you shouldn’t compare your heart rate variability with other people, because HRV is affected by a number of internal and external factors, such as age, hormones and the overall body functions, as well as lifestyle.

You can still compare (for information purposes) to this table which depicts a picture of average HRV’s depending on your age and condition if you really want to. But it makes more sense to react accordingly to what your body needs, and not go for under or over realistic goals stated in this table.

HRV Norms Circular


HRV analysis is important for your wellbeing. The whole point is for you to understand what is causing a drop in HRV and if you are recovering or not. If you make changes to improve your HRV and act accordingly you will get rid of stress inducers and any negative action your body does not need. As weird as it seems, this simple metric is a very powerful tool and can get you very precise insights about your wellbeing. 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.