How Fitness Trackers Track Sleep – Are They Accurate?

An estimated 70 million Americans struggle with chronic sleep disorders. How do you know your luck of sleep is a problem that needs to be addressed? Well, fitness trackers and smartwatches are designed to provide insights into sleep quality to help you understand your sleep patterns.

Now this begs the question? How do they work, and are they even accurate?

Let’s cover this topic in detail, looking at how these trackers work, their accuracy rate, and more!

How Exactly Do Fitness Trackers Track Your Sleep?

Fitness trackers have become popular not only for monitoring daily activity, but also for their ability to provide insight into sleep habits. But how exactly do these devices detect when you fall asleep, time your sleep stages, and analyze your sleep quality?

Let’s take a look under the hood.

How Fitness Trackers Track Sleep

How Fitness Trackers Track Sleep Infographic

Sleep tracking starts with sensors:

  • Accelerometers – This sensor detects motion and orientation, allowing the tracker to identify when you lie down and your movement ceases, signaling sleep onset.
  • Optical heart rate sensors – Monitoring your heart rate patterns contributes to determining sleep stages. Heart rate declines when transitioning into deep sleep.
  • Additional sensors – More advanced trackers may also use skin temperature, ambient light, and sound-based respiration sensors to enhance accuracy.

Intelligent algorithms then make sense of this sensor data

  • The tracker applies proprietary algorithms to the accelerometer data to distinguish rest from sustained sleep based on minimal movement for a period of time.
  • Heart rate data is synchronized to pinpoint rapid, irregular motionlessness indicating REM sleep versus deeper sleep’s steady, slower heartbeat.
  • Machine learning fine-tunes these algorithms over time based on comparing sensor inputs to user sleep logs and feedback.

Finally, sleep stages are quantified

  • Light sleep is characterized by occasional movement and faster heart rate as muscles relax.
  • Slow, regular heart rhythms coupled with no motion is classified as deep sleep when restoration occurs.
  • REM sleep shows an uptick in pulse alongside continued stillness based on the synchronized sensor data.

How Accurate Are Fitness Trackers for Sleep?

Fitness trackers record your sleeping patterns, whereas some like Fitbit can measure the amount of time spent on every stage of your sleep. However, most users are still wondering if it provides accurate data that can help improve their sleep patterns. Here’s how Fitbit devices work to give you precise and useful information.

A Fitbit fitness device comes with sleep mode technology that detects the moment when the users shut their eyes. It calculates the time spent asleep and the number of times you woke up or got restless. Besides, the fitness device is equipped with an accelerometer that accurately detects motion speed and direction.

How Can You Track Your Sleep?

Calculating the hours you slept and whether the sleep was smooth or if you had some sleep disturbance is challenging. Waking up tired or getting up late in the morning are common indicators that your sleep had some interruptions. However, with a fitness tracker, you can easily monitor your sleep habits.

Various Fitbit models, such as Motiv Ring, the Huawei band, and the Apple Watch, efficiently track your movements during the night. These devices are programmed to provide data that you can record and reset every morning. This information can help you to adopt a healthy sleeping pattern.

Why Does Your Fitbit Not Track Your Sleep?

Fitbit tracking device starts tracking your sleep automatically when it detects no movement. However, several issues can affect the performance of your device. Here’s what to do to enhance the performance of your sleep-tracking gadget.

1. Tighten It Around Your Wrist

The tracker might become inconsistent if it is not firmly placed around your wrist. Start by tightening it. If this doesn’t work, change it to the other wrist, or with help there are fitness trackers for small wrist in the market. For a Fitbit sleep tracker to work efficiently, it has to read your heart rate consistently. Besides, you have to sleep for at least 3 hours for the app to provide accurate information on your sleeping stages.

2. Change the Battery

Over time, the battery might get low, and the device may stop sleep tracking when the battery power is too low. Change the batteries when necessary to avoid these inconveniences.

3. Change Sleep Sensitivity

Did you know that a Fitbit app (Android or Apple) has settings where you can change sleep sensitivity? In your device menu, press the Accounts tab, then select Advanced Settings. From the Sleep Sensitivity tab, select the desired setting from the provided options.

The app is mostly set at default, whereby it only keeps count of significant movement when you’re awake. However, a change of settings can lead to the recording of even the slightest movement. Keep adjusting until it finally makes the desired difference.

4. Reboot the Device

A small technical problem can stop the Fitbit device from optimal performance. Reboot the wearable by holding its back left and right buttons altogether for 10 seconds. The device logo will pop up a few seconds later after switching off. This indicates that the device has successfully started.

Will you lose the Fitbit data once you restart it? Unlike other devices, the Fitbit App does not delete its stored data. It is, therefore, safe to reboot it whenever you experience some anomalies.

How Do Sleep Tracker Apps Work

Sleep tracking gadgets calculate the time a user spends asleep and analyze the quality of their sleep. Besides, they determine the time taken to sleep in every stage and examine various factors that can interrupt sleep, including lights and the temperature levels in the bedroom.

Are you wondering how the trackers realize when you’re asleep? The device measures your body motion through accelerometry and actigraphs. Some can capture noise emanating from your body via an installed microphone. By measuring room temperature, capturing heartbeat rate, and using motion sensors, sleep tracking apps deliver accurate information.

How Does Fitbit Track Sleep Stages

Your body goes through several sleep cycles, which can last for 90 minutes whenever you sleep. These cycles are classified as light and deep sleep. The Fitbit gadget has a combination that estimates heart rate and movement patterns. It tracks the transition between your sleep stages through Heart Rate Variability.

How Does Huawei Band Track Sleep?

Huawei band track sleep automatically records your sleeping information. Data recorded varies from light to deep sleep. While wearing this band, the user can get the sleep data by viewing it on the band or using a Huawei Health App. However, you must wear it tightly around your wrist to get the correct data.

Are you struggling with sleep and wondering how you can monitor your sleep patterns? Get one of these fitness trackers to determine your sleep pattern and work for a better sleeping habits.

Common Questions

How do fitness trackers automatically detect sleep?

They use accelerometers to sense motion paired with algorithms that recognize sustained inactivity as sleep vs. just resting. Heart rate dropping also indicates sleep.

Do they accurately measure sleep stages?

Basic trackers estimate sleep stages based on motion and heart rate changes. Advanced models like Fitbit Sense come closer to clinical sleep study accuracy through additional sensors.

Can trackers detect sleep disorders like apnea?

Wearable consumer trackers alone cannot diagnose sleep disorders. But they can spot sleep disturbance patterns and duration for further professional evaluation.

What sleep metrics can trackers monitor? 

Most fitness bands detect total sleep duration, periods of Light/REM/Deep sleep, and sleep adequacy. Advanced models add blood oxygen levels, breathing disturbances, and heart health data.

How does sleep data from a tracker help users?

Seeing sleep trends helps users prioritize proper rest. Insights also allow modifying habits that impair sleep and help determine if a clinical sleep assessment is warranted.