Fitbit's Sleep Tracking: Does It Monitor Sleepwalking?

Fitbit devices are popular for their ability to track sleep. Fitbits can monitor sleep by tracking movement and heart rate patterns. The device assumes you are asleep when there is no movement for about an hour. It can also detect restless sleep through the way your body moves. Fitbits with heart rate monitors can discern between light sleep, deep sleep, and REM sleep. The data collected by the device can be viewed in the Fitbit app, which provides a sleep score based on heart rate, time spent awake or restless, and sleep stages. Fitbit Premium offers additional insights and tools to help improve sleep quality. While Fitbit's sleep tracking features are useful, they are not intended to diagnose or treat medical conditions.

Fitbit sleep score

The Fitbit sleep score is a quick way to gauge your sleep quality. The score is based on heart rate, the time spent awake or restless, and sleep stages. The overall sleep score is a sum of individual scores for time asleep, deep and REM sleep, and restoration, for a total score of up to 100. Fitbit devices track the beat-to-beat changes in your heart rate, known as heart rate variability (HRV). These numbers fluctuate as you transition between light sleep, deep sleep, and REM sleep stages. When you sync your device in the morning, Fitbit uses movement and heart rate patterns to estimate sleep cycles from the previous night.

The Fitbit sleep score is available on the Today tab in the Fitbit app. To check your sleep score, tap the Sleep duration tile. You can also swipe up from the clock face to see your daily stats, including your most recent sleep session. To review stats for previous days, tap the arrow icons next to the current day to move forward or backward by a single day. Use the week, month, or year tabs to navigate to days in the past, and tap a sleep session. You can also check your sleep score from your wrist on certain devices. For example, on the Fitbit Sense 2 and Fitbit Versa 4, swipe left or right from the clock face to find the Sleep tile. Your sleep score is displayed under the sleep duration.

Fitbit Premium offers a detailed breakdown of your sleep score, including analysis of your sleeping heart rate. Fitbit Premium also provides access to guided programs developed with sleep experts, including Habits for Restful Sleep, which helps users build better daytime habits to achieve deeper sleep at night, and Get More Sleep, which helps users improve their nighttime routine and work towards longer sleep with goals and relaxation tools.

Fitbit's sleep feature estimates sleep stages using a combination of movement and heart rate patterns. When you haven't moved for about an hour, your tracker or smartwatch assumes that you're asleep. Additional data, such as the length of time of movements that are indicative of sleep behavior (such as rolling over), can also help confirm that you're asleep. To accurately track your sleep, make sure your device is positioned higher on your wrist, about 2-3 finger widths above the wrist bone. The band should feel secure but not too tight.

Sleep stages

Sleep is an essential component of health, and its timing, duration, and quality are critical determinants of a person's overall health. The two main phases of sleep are rapid eye movement (REM) and non-rapid eye movement (NREM) sleep. NREM sleep is further divided into three stages: N1, N2, and N3.

N1 is the lightest stage of sleep, normally lasting just one to seven minutes, making up about 5% of your sleep time. During this stage, the body has not fully relaxed, though the body and brain activities start to slow, with periods of brief movements. It is easy to wake someone up during this sleep stage, but if uninterrupted, they can quickly move into N2.

N2 is deeper than N1, where your brain waves slow down and have noticeable pauses between short, powerful bursts of electrical activity. Experts believe that these bursts are the brain organizing memories and information from the time spent awake. N2 accounts for about 45% of your time asleep (the most of any stage). You will go through multiple rounds of N2, and usually, each one is longer than the last.

N3 is the deepest stage of NREM sleep, making up about 25% of your total sleep time in adults. During this stage, your brain waves are slow but strong, and your body takes advantage of this very deep sleep stage to repair injuries and reinforce your immune system. The same bursts of brain activity that happen in N2 can also happen in N3, and brain waves specific to N3 help regulate those bursts. You need N3 sleep to wake up feeling rested. Without enough N3 sleep, you will feel tired and drained, even if you slept for a long time.

After N3, the body moves into REM sleep, where vivid dreams are more likely to occur. The duration spent in each sleep stage varies with age, often reflecting a decline in the overall biological necessity for sleep over time. Sleep timing in newborns, for example, is distributed evenly across day and night for the first few weeks of life, with irregular sleeping and waking patterns. Newborns sleep approximately 16 to 18 hours per day discontinuously, with the longest continuous sleep episode typically lasting 2.5 to 4 hours.

Heart rate variability

While it is not explicitly mentioned whether Fitbit can track sleepwalking, the device can monitor your sleep and sleep patterns. Fitbit's sleep feature estimates sleep stages using a combination of movement and heart rate patterns. The device can track the amount of time you are asleep, as well as the quality of sleep you are getting. It can also track the beat-to-beat changes in your heart rate, known as heart rate variability (HRV).

Your heart rate is controlled by your autonomic nervous system (ANS), which also regulates your blood pressure, breathing, digestion, and other automatic functions. The ANS has two main parts: the sympathetic nervous system and the parasympathetic nervous system. The sympathetic nervous system, also known as the fight-or-flight response, increases your heart rate and blood pressure in response to stressors, including exercise. On the other hand, the parasympathetic nervous system, also known as the rest-and-digest or relaxation response, slows down your heart rate and blood pressure when you are calm, relaxed, or sleeping.

It is important to note that while wearable devices like Fitbit can help detect heart rate irregularities, they are not intended to diagnose or treat any medical conditions. If you have any concerns about your heart rate or sleep patterns, it is recommended to consult a healthcare professional.

Sleep patterns

Sleep is an essential component of health, and its timing, duration, and quality are critical determinants of a person's overall health, playing a role in metabolic and emotional regulation, performance, and memory. Fitbit devices can help you track your sleep patterns and recognise when you need to get more rest and recharge.

Fitbit's sleep feature estimates sleep stages using a combination of movement and heart-rate patterns. When you haven't moved for about an hour, your tracker or smartwatch assumes that you're asleep. Additional data, such as the length of time of movements that are indicative of sleep behaviour (such as rolling over), can also help confirm that you're asleep. Fitbit devices with heart rate monitors can discern between light sleep, deep sleep, and REM sleep, with the latter being associated with vivid dreams.

The Sleep Profile feature, a more detailed breakdown of your sleep, is available on specific models, including the Charge 5, Charge 6, Inspire 2, Inspire 3, or Luxe tracker, or any Sense or Versa watch (except the original 2018 model). The Sleep Profile feature requires a Fitbit Premium subscription, which costs $10 a month and provides access to a range of extra insights, sleep aids, and audio tracks.

The Fitbit app offers a Sleep Score, which is a quick way to gauge your sleep quality. This score is based on heart rate, the time spent awake or restless, and sleep stages. The overall sleep score is a sum of individual scores in three components: sleep duration, sleep quality, and restoration, for a total score of up to 100. Most Fitbit users get a sleep score between 72 and 83, which is considered fair or good. An excellent sleep score is considered to be above 90.

Fitbit also offers tools and programs to help you improve your sleep habits and achieve deeper sleep. These include the "Habits for Restful Sleep" program, which provides guidance on building better daytime habits for improved nighttime sleep. Additionally, the "Get More Sleep" program helps you work towards longer sleep by setting goals and providing relaxation tools.

Sleep tracking accuracy

Sleep tracking devices have become increasingly popular, with one in three Americans having used a sleep-tracking device. These devices are a practical, cost-effective tool for monitoring individual sleep habits. While they do not directly measure sleep, they can provide valuable insights into sleep patterns and sleep quality.

Fitbit devices are among the most popular sleep trackers on the market. They can automatically detect your sleep when worn to bed and can track the amount and quality of sleep you're getting. Fitbit's sleep feature estimates sleep stages by combining movement and heart rate patterns. When your body is completely at rest and hasn't moved for about an hour, your Fitbit records that you're asleep. It can also detect restless sleep and time spent awake by tracking excessive movement.

Fitbit devices with heart rate monitors can differentiate between light sleep, deep sleep, and REM sleep. They track the beat-to-beat changes in your heart rate, known as heart rate variability (HRV), which fluctuates as you transition between sleep stages. The Fitbit Sleep Score is a quick way to gauge your sleep, based on heart rate, time spent awake or restless, and sleep stages.

While Fitbit devices provide a wealth of sleep data, their accuracy has been questioned. Some studies have validated the accuracy of Fitbit devices against in-lab polysomnography, with specific models like the Fitbit Sense 2 and Google Pixel Watch showing superiority in the deep sleep stage. However, there is a need for more comprehensive research to confirm the reliability of these devices as the technology continues to evolve.

It's important to note that sleep trackers should not be solely relied upon for medical purposes. If you have concerns about your sleep quality, consulting a healthcare professional is recommended. They can advise on exact data through medical sleep studies that monitor brain waves and help diagnose sleep disorders. Nevertheless, Fitbit devices and other sleep trackers can be valuable tools for recognizing patterns in your sleep habits and making informed decisions about your sleep routine.

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