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What is the Circular® Sleep quality score and how it is calculated

Although Circular analyzes many of your sleep parameters to help you determine your trends and ways for you to improve your sleep, we have created a tool so that you can see at a glance whether your sleep was restorative or not.

With sleep specialists, we have built a Sleep quality score that includes all the parameters calculated by Circular and that fully reflects the quality of your night.

As with all Circular scores, a score equal or above 90 is Excellent, from 80 to 89 is Good and below 80 is Poor.

The Sleep quality score is a daily score that is composed of your last night:

  • Total sleep 
  • Real sleep
  • Sleep debt 
  • Time to fall asleep (sleep latency)
  • Deep sleep
  • Rem sleep
  • Circadian rhythm 
  • Motion during sleep (tranquility)

All these parameters have different coefficients depending on their importance.

Your daily Sleep quality score is found after each night at the top of the Sleep analysis circle. You can find the different factors composing the Sleep quality score in the "daily sleep details" section.

You might have already seen recommendations in your feed stating that your Sleep quality is excellent. Or on the contrary, Kira might have told you that your Sleep quality for the week was poor. 

Let’s note that you receive these recommendations only if your overall sleep is very poor or very good.

Let’s see in depth what is taken into consideration in the Sleep quality score and what are the implications for you.

Total Sleep

Total Sleep refers to the total time you tried, could or spend to sleep. That is, from the time you fall asleep until you wake up permanently including the time counted as disturbances. If you have made micro-awakes or you were awake for 30 minutes during your night, this time is counted as part of total sleep since it is time you could have slept. Total sleep looks at how much your sleep is, compared to your personal sleeping length needs. This, to evaluate  if you make the effort to spend enough time sleeping to get a restorative sleep.

Real Sleep

While total sleep includes the entire sleep period without taking into account the time of sleep lost within this period (disturbances), real sleep looks at the time you actually slept during your total sleep period. In fact, it evaluates your disturbances since real sleep is total sleep minus disturbances.

Time to fall asleep

Better known as sleep latency, the metric quantifies the length of time that it takes to accomplish the transition from full wakefulness to sleep. Kira calculated your baseline sleep latency which corresponds to your sleep latency average. Variations from this baseline are evaluated. The calculation also takes into account the scientific literature which stipulates that you should not fall asleep in less than 5 minutes because it reflects lack of sleep and in more than 30 minutes.

Sleep debt

Sleep debt is the cumulative effect of not getting enough sleep or getting too much sleep. Either one is bad for your body. Sleep debt looks at how much you have actually slept (real sleep) compared to your personal sleeping length needs. The higher the deviation from your personal needs (whether it’s higher or lower), the more it will negatively impact your sleep debt indicator. 

REM sleep

REM sleep is the sleep stage that is responsible for restoration and memory consolidation. The recommended average for adults depends on a lot of factors including age for example. It is usually around 20% to 25% of your total sleep for an adult. Kira knows your needs and your sleep cycle habits. It will assess whether or not you had enough REM compared to you and what you need.

Deep sleep

It is the sleep stage that allows repairing muscles and tissues, that stimulates growth and development, boosts immune function, and builds up energy for the next day. As for your REM sleep, Kira knows your needs and will take into consideration if you had enough deep sleep or if you are deprived of it to measure overall sleep quality. It is usually around 15% to 20% of your total sleep for an adult.

Circadian rhythm

Your circadian rhythm is basically a 24-hour internal clock that is running in the background of your brain between sleepiness and alertness at regular intervals. It's also known as your sleep/wake cycle. It is tremendously important to sleep during darkness and follow a regular sleep schedule because it directly impacts your overall sleep quality. Kira will notice if you sleep during the good period (beginning, middle and end of your sleep) and compare automatically your usual sleep schedule to your last nights to determine whether you are respecting your rhythm or not.


It determines how much you have moved during your sleep. An agitated night is often a sign of less restorative sleep. The score is divided into 3 indicators: agitated, still and peaceful.

To conclude

The Sleep quality score is updated after each sleep period whether it's your core sleep or a nap. Your nap quality score will complete your Sleep quality score to really reflect the quality of your daily total sleep. 

Your daily Sleep quality score can allow you to monitor the evolution of your sleep by comparing it with your other sleep periods at the bottom of the ‘Sleep analysis’ circle in the "sleep graphs" section. You can also compare your Sleep quality score on a broader scale. 

The Sleep quality score is also used for Kira’s recommendations and for your leaderboards score.

You can also read What is the nap quality score and how it is calculated that completes this article.
The Sleep quality score is part of the Circular® Global score, click here to learn about it.

Sihem Kime

Chief Data Scientist at Circular, Sihem is passionate about healthcare and machine learning. She practices swimming, cycling and running which makes her the fittest to design Circular algorithms.

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