How does Fitbit track sleep? (7 tips)

In this guide, we will discuss How does Fitbit track sleep, How does Fitbit detect sleep stages, what are the sleep stages and instructions on How to view those stages. Additionally, some other features and options will allow you, for instance, to see how many times during the night you woke up or for how long you were in deep sleep based on your heart rate and movements.

How does Fitbit track sleep?

If you wonder, ‘How does Fitbit track sleep’ it pretty much resembles any other wearable in the sense that Fitbit calculates or estimates your sleep stages by using a combination of movements while you sleep and your heart-rate patterns. When you haven’t been moving for an hour, the tracker or watch will assume you are asleep. Additionally, the length of time of your movements may indicate the Fitbit your sleep behaviour or pattern.

As you may probably know, when you are sleeping, you go through several sleep cycles that last 90 minutes on average. In each cycle, you alternate between two types of sleep, which are Light Sleep and Deep Sleep. During a sleep cycle, it is normal to alternate between light and deep sleep and then into REM sleep. This cycle generally repeats but the patterns vary naturally.

The Rapid Eye Movement Sleep or REM stage is associated with dreaming and these periods are typically longer as the night goes on. 

How does the Fitbit detect my sleep stages?

Usually, sleep stages are measured in a lab using a method called electroencephalogram to detect your brain activity along with other systems to monitor your muscle and eye movements. Even if this method is considered the gold standard for measuring sleep stages, your Fitbit may estimate your sleep stages more conveniently since there is no need to be connected to any type of electrodes or machines.

As indicated on, “Fitbit estimates your sleep stages using a combination of your movement and heart-rate patterns. When you haven’t moved for about an hour, your tracker or watch assumes that you’re asleep. Additional data—such as the length of time your movements are indicative of sleep behaviour (such as rolling over, etc.)—help confirm that you’re asleep”.

Moreover, the changes in your heart rate variability which changes as you transition from one sleep stage to the other, your device will use this data and your movements throughout the night to estimate your sleep cycles. 

Sleep stages

The following sleep stages are the ones included in your Fitbit sleep log, which lets you understand a bit more about them. 

Light Sleep

This stage begins within minutes of falling asleep and during the early part of this stage, you may alternate between awake and asleep. Light sleep serves as the entry point into sleep each night as your body unwinds and slows down. This stage is believed to help you recover mentally and physically.

Deep Sleep 

this stage usually happens within the first few hours of sleep. You may have felt refreshed and energized in the morning, so this means you have experienced periods of deep sleep the previous night. During this phase, it becomes harder to be awakened since your body becomes less unresponsive. This helps prevent you from acting out on your dreams. Deep sleep is suggested to promote physical recovery and certain aspects of memory and learning. 

REM Sleep

The first phase of Rapid Eye Movement sleep will typically happen after the first stage of deep sleep. This phase usually lasts for a longer period of time during sleep cycles that occur in the second half of the night. It is considered the final step and it is when your brain becomes more active. 

As indicated on, “Dreams mainly occur during REM sleep, and your eyes move quickly in different directions. Heart rate increases and breathing becomes more irregular. In principle, muscles below the neck are inactive to avoid acting out dreams”. 

Instructions on how to see your sleep stages

If you would like to see your sleep stages in the Fitbit app follow these instructions:

  • When you wake up, open the Fitbit app and sync your Fitbit device.
  • Tap the sleep tile but if it says ‘Analyzing your sleep’ it means it is not synced yet so go back to the first step.
  • Tap ‘Today’ or if you are using windows 10, tap ‘Last Night’.
  • Tap the expand icon in the top right to open information about your sleep stages, and swipe to view your stats. Tap the icon again to close.
  • Tap ‘30 Day Avg’ by scrolling down to the view time spent in each stage.
  • Scroll down to view your time spent in each stage, and tap 30 Day Avg and Benchmark to view additional stats. 

Will I see how many times I woke up?

It is considered normal if you see awake minutes in the data tracked since studies suggest that a typical adult can wake up briefly on average between 10 to 30 times a night. You may not remember waking up since you will likely go back to sleep, especially if you are awake just for a couple of minutes. 

However, you may have been feeling tired and drowsy the next morning. The number of times you see awake minutes can let you know about the quality of your sleep. If you have been tracking your sleep for a while, your Fitbit log will include the time you spent awake, restless, and asleep. The device will give you an estimate of your sleep stages and will also include your heart rate and additional data. 

What happens if I don’t see any sleep stages?

There are some reasons why you might not see the report of your sleep stages and they are:

  • The position you slept in prevented your Fitbit from getting a consistent measure of your heart rate or you ended up wearing it too loosely. To improve the results, wear your device higher on your wrist when possible and it should feel secure but not too tight.
  • If you have used the Begin Sleep Now option on the app instead of simply wearing your device when going to bed, it may show some inaccurate details.
  • If you have slept less than three hours of if your device’s battery is critically low, the data may not be reflected. 

For additional information on your recorded sleep pattern, you can tap on the sleep record that appears on the sleep pattern. 

Why is this blog about How does Fitbit track sleep important?

To know how Fitbit tracks sleep seems to be important to many users and it may be the reason why they got the device in the first place. As we have discussed, Fitbit is said to be accurate when measuring your sleep and track sleep stages. Additionally, the interface is user friendly, allowing you to retrieve the information in a fast and easy way. 

However, consider that in certain circumstances you may not see the sleep stages reflected on the data so it is important to verify if the reason why is because you have slept less than 3 hours the night before or your device’s battery was critically low to record the information.

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Frequently Asked Questions (FAQs) about How does Fitbit track sleep

Is Fitbit accurate for sleep?

According to the results of Fitbit’s study, which were scored independently by polysomnography technologists have demonstrated that these devices can track sleep stages with a reasonable degree of accuracy in normal adults. 

Does Fitbit automatically track sleep?

Fitbit will automatically track or detect sleep when you wear the device when going to bed. After an hour of inactivity, it will start recording your sleep pattern based on the movements. If your device does not include heart rate monitoring, you will see your sleep pattern in the fit bit app. Your sleep pattern will include the time you spent awake, restless and asleep.

Does the Fitbit One track sleep?

Fitbit One can track how long and how well you slept. This device will also track your movements throughout the night to let you know about the quality of your sleep. Just simply place the tracker into the slot in your wristband and wrap it around your non-dominant wrist, go to sleep with it and check on your results the next morning.

What is a good sleep score on Fitbit?

A good sleep score on Fitbit ranges between 80-89 and excellent would be between 90-100. However, most people get a score between 72 and 83.

Can Fitbit detect sleep apnea?

Fitbit can detect sleep disturbances such as sleep apnea with the new tracking feature called Sleep Score beta (SpO2). Sleep disturbances could indicate health issues such as allergies or asthma, among others. The new Fitbit Charge 3 is part of Fitbit’s bigger goal of developing FDA-regulated software for sleep and heart conditions.


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