How Do Smartwatches Monitor Sleep?

Smartwatches and wearables are becoming more and more popular, but just how do they help you sleep at night?

Summary: Smartwatches and Sleep

● Sleep coaching: Personalised 4-to-5-week programme is designed to help improve your overall sleep quality.

● Bedtime Guidance: Gives personalised guidance on when to head to bed to make sure you’re getting good quality sleep.

● Sleep Score: Samsung Galaxy Watches provide a Sleep Score ranging from 1 to 100 to measure the quality of your sleep to gauge whether you’ve had sufficient R&R to tackle your next workout or weekend run.

What Smartwatch Sensors Help with Sleep Tracking?

Your Samsung Galaxy smartwatch is able to track the quality of your sleep taking into account factors like hear rate variability, skin temperature, SPO2 and more. These all build a picture to provide a holistic view of your sleeping habits and how best to improve them.

Galaxy Watch Ultra2 is always monitoring your vitals so that it’s able to detect any irregularities within your sleeping data.

Accelerometer

The built-in accelerometer on your Galaxy Smartwatch is able to detect your movement while you sleep in the same way it tracks your exercise. The deeper asleep you are, the less you move. If you are tossing and turning trying to fall asleep, or in a lighter sleep stage, your accelerometer will be able to detect this.

Heart Rate Sensor

Detectable by the heart rate sensor on your Galaxy Smartwatch, heart rate is factored into your Sleep Score and Sleep Stage data. Heart Health Score is on hand to give you suggestions based on your sleep, daily activity and BMI, so you can gauge if you’ve had sufficient R&R to tackle your next workout or weekend run.

Infrared Sensor

The latest Galaxy Smartwatches are built with infrared sensors at their core. These track fluctuations in your skin’s temperature and also your blood oxygen levels. These help to provide information around your sleep quality and environment, which contribute to how restored you feel when you wake up.

Samsung Galaxy Watch Ultra2

Samsung Galaxy Watch9

Samsung Galaxy Ring

Samsung Galaxy Fold8

How Does a Smartwatch Interpret Sleep Stages?

The Samsung Health app is able to combine the data it and your wearable collects while you sleep to create a picture of how deeply you are sleeping. On your wrist and in the app on your Galaxy Smartphone, your sleep is graded by:

● Light Sleep: You’re just drifting off, still moving around but not yet in the most effective stages of recovery. It’s easy to wake up from light sleep.
● REM (Rapid Eye Movement): This is the stage where brain activity surges, the most mentally restorative phrase, and where people dream. Your body typically remains still during this stage while your brain is consolidating memories and processing your day’s activities.
● Deep Sleep: Deep sleep is the hardest to wake up from, and is essential for physical restoration.

What Does a Sleep Tracker Actually Show You in the Morning?

While you sleep, your Galaxy Smartwatch or Galaxy Ring is hard at work collecting data about how you’re recovering. Sleep coaching lets you track your heart rate variability (HRV), SpO2 and respiratory rate through the night1. When you wake up in the morning, your energy and sleep scores let you know how you got on, taking into account the following metrics.

Sleep Time

How many hours and minutes you were asleep for. You can compare this to the previous day, week, month, depending on how long you have been wearing your Galaxy device. Sleep Time can be measured by your Samsung Galaxy smartphone, but more detailed health metrics can be unlocked by pairing it with your Galaxy wearable.

Sleep Score

Samsung Health will provide you with a Sleep Score on a scale from 1-100 ranging through Excellent, Good, Fair, and Needs attention. This will take into account the length and quality of your sleep to create a rating of how restorative your sleep was.

Sleep Stages

The sensors at the Galaxy smartwatch’s core will work to paint a picture of how long you were in each sleep stage. This helps to explain how deeply you were asleep to predict how mentally and physically restored you will feel for tomorrow’s big workout or next long run in your current half marathon training block.

Blood Oxygen During Sleep

More advanced Galaxy Smartwatches are able to measure SpO2, which is an estimation of how much oxygen is in your blood. This is not only to ensure you are recovering well after adventurous days out on the trails, but also for early signs of any abnormalities that could be caused by underlying factors.

Snore Detection

The microphone on your Galaxy smartwatch can also detect any snoring while you are asleep if you allow it. This can pair with the Sleep Apnea detection feature within Samsung Health Monitor to deliver early detection, or help to explain why your sleep might feel so disrupted, even after a day full of activity.

Sleep Apnea Risk Detection

The Sleep Apnea feature2 on the new Galaxy Watch9 uses your Samsung Galaxy watch and smartphone to detect signs of moderate to severe obstructive sleep apnea (OSA) over a two-night monitoring period.

Sleep Skin Temperature

Your Smartwatch’s infrared sensor can detect your body’s skin temperature from your previous night’s sleep. This is a great way to track monthly menstrual cycles, monitor recovery from training as your base temperature returns to normal, and gauge workout strain as you spend days out climbing mountains or navigating commuter runs.

Sleep Consistency

Samsung Health will compare your sleep quality to what your goal should be, which can be changeable depending on your fitness goals. For example, your sleep goals might be higher if you are in active recovery rather than if you are on a rest week. You can note patterns, such as sleeping better after longer runs or worse sleep quality after a few beers, so that you can plan better recovery around more difficult workouts.

How Accurate is Smartwatch Sleep Monitoring?

The overall sleep duration and timing tracking on Samsung Galaxy devices offer great accuracy. The ultimate goal of Sleep Tracking on Samsung Health is to monitor your overall wellness, including trends in long term sleep data, to help you better your habits when it comes to sleep. With Advanced Sleep Tracking3, the Galaxy Watch Ultra2 allows you to prioritise rest and recovery and get more out of bedtime.

When it comes to the Samsung Galaxy Watch’s sleep apnea risk detection2, it’s a CE marked medical feature. In detecting signs of moderate-to-severe OSA, the feature achieves 82.7% sensitivity and 87.7% specificity.

Tips for getting the Best Sleep Data

Consistent Wear

In order for the Samsung Health App to provide accurate sleep coaching data, it’s key that you wear your Galaxy Watch for at least 7 days. After this, the collected data can begin to benchmark your sleep quality and provide tips for your nightly recovery. For the most useful trend data, it’s also important to continue wearing your fitness tracker consistently.

The Galaxy Watch Ultra2 is built for all-day comfort, with a soft, cushioned strap for continuous wear, all day, all night, and all week.

Proper Placement

It’s not just important for you to wear your Galaxy Watch consistently, but also consistently correctly. It should be worn snugly, though not too tightly as to become uncomfortable, on your non-dominant wrist. This allows the optical heart rate sensors to become and continue to be enabled for accurate data readings.

The new Galaxy Watch Ultra2 features a cushioned soft-tough band, comfortable to wear all night, so nothing distracts you from getting your full eight hours.

Charged Fully

It’s also important that you keep an eye on your Smartwatch battery to ensure that it won’t run out of charge while you sleep. Sleep Mode ensures that less battery is used during the night so you and your watch are ready to go first thing. Being able to capture data all night and over at least a few days is important to build an accurate picture of your sleeping habits.

Get more out of every run, swim and sleep with Galaxy Watch9, thanks to a massive battery4 and super-accurate health tracking.

Our Best Fitness & Sleep Trackers

The Galaxy Watch9 is the easiest way to manage your health, with in-depth health tracking and advanced 24/7 monitoring. Its range of smart sensors is capable of tracking workouts and monitoring heart health as well as reporting on your sleep quality each night. From night to day, its massive battery and advanced processor means that everything keeps running smoothly in order to deliver super-accurate health tracking. Maintaining a healthy lifestyle starts with a happy heart and good night’s sleep. With so many data points specific to you, Galaxy Watch9 can guide you towards both – so you can make a start on tomorrow, tonight.

If you are striving to fine-tune your fitness and keep a close eye on advanced health tracking data, the Galaxy Watch Ultra2 is built to push you further than ever. Track vitals while you test your limits, so that adventurers, hikers and trail runners can keep on top of everything you need to know, including energy levels and sleep data. Built with sleep apnea risk detection2 and severity level monitoring, you can start working towards achieving better rest.

Discover the latest in fitness and sleep tracking technology in our Galaxy wearables and shop now.

Samsung Galaxy Watch Ultra2

Samsung Galaxy Watch9

Samsung Galaxy Ring

Samsung Galaxy Fold8

Frequently Asked Questions

  • What is the best smartwatch for tracking sleep?

    The best smartwatch for sleep tracking is the Galaxy Watch Ultra2, as it goes beyond simply telling you how long you slept. It's important to look for a watch that monitors sleep stages, heart rate and blood oxygen, and also presents all the data in a way that's easy to digest when you wake up. You also want to have a strap comfortable enough to wear all night without getting in the way of your 8 hours.

  • In terms of accuracy, smartwatches have come a long way since they were first developed. Galaxy smartwatches are genuinely useful to spotting patterns, trends, and monitoring your sleep within the wider health insight picture. The key is consistency, so wearing your watch every night will provide a much clearer picture of your sleep and heart health than a single night's reading.

  • Galaxy Watch9 is able to detect early signs of sleep apnea2, giving you a severity scale. This helps you take action when needed and start working towards achieving better rest.

  • Sleep tracking should work automatically once you have worn your Galaxy wearable for at least 3 night's sleep. Some smartwatches have a dedicated sleep mode that you can switch on manually, but setup is usually minimal before you can start learning from your sleep insights.

1. Intended for general wellness and fitness purposes only. Not intended for use in detection, diagnosis, treatment of any medical condition or sleep disorder. Bedtime guidance is based on three days of sleep analysis of users’ circadian rhythm and sleep pressure.

2. Requires a Galaxy smartphone running Android 12 or above. Do not use feature if you are pregnant or have previously been diagnosed with sleep apnea. 22 years+ only. Intended to detect signs of moderate to severe obstructive sleep apnea over a two-night period. Feature will not detect central sleep apnea. Does not replace diagnosis or treatment by a healthcare professional.

3. Requires smartphone operating on Android 11 or above with Google Mobile Services and the latest version of the Samsung Health app. Samsung account login and Galaxy smartphone is required for certain AI features.

4. 20% larger compared to previous Galaxy Watch8 40mm for 40mm size.