How to track your sleep stages with Apple Watch

apple sleep stages release

Apple finally released the function we’ve all been asking for, a better sleep tracking system! In the new watchOS 9 and iOS 16 updates, Apple Watch users can now track sleep stages with Apple Watch. 

So if you used SleepCycle or another third-party sleep tracking app, consider trying out Apple’s native Sleep app in watchOS 9+ and see if it suits your needs.

Apple’s new sleep tracking feature now logs your sleep into different stages like REM, core, and deep sleep, and your Apple Watch gets data using the accelerometer and heart rate monitor.

Sleep stages are available on Apple Watch Ultra, SE, and Series 4+. This feature is unavailable on Series 3 Apple Watches since it requires watchOS 9+ and iOS 16+.

So how exactly can you track your sleep stages with Apple Watch? Keep reading to learn more.

Suggested reading:

What are the sleep stages?

Sleep association person sleeping

If you’re not familiar with what sleep stages are, have no fear, let’s break it down. Sleep occurs in cycles. According to most sleep experts, there are four sleep cycles, which are also known as stages. 

The four stages are awake, light, deep, and REM. Now, your Apple device doesn’t use these exact terms when tracking your sleep. Instead, they focus on core sleep, deep sleep, and REM. You can also see your time awake as well.

Core sleep is the equivalent of light sleep and takes place in the first few hours of your sleep. It is the most essential sleep stage. 

Deep sleep is exactly what it sounds like. It is the phase of the sleep cycle where it is harder to wake someone up.

Deep sleep is the most important sleep stage because it lets your body release growth hormone and works to build and repair muscles, bones, and tissue. Plus, it helps keep your immune system functioning.

REM stands for rapid eye movement and occurs at intervals during the late part of the night. It is considered to be optional sleep that is less crucial.

How to track sleep stages with Apple Watch Sleep stages on Apple Watch in Sleep app

So how does your Apple Watch track these three different sleep stages? Well, your smartwatch uses signals from the accelerometer and heart rate sensor, which detects when you are in the core, REM, or deep sleep cycle. 

Now, if you don’t own an Apple Watch, you can still track time in bed with your iPhone, but you won’t be able to track your sleep stages! Your phone gathers information on your sleep based on whether or not you pick up and use your iPhone during the night.

Your device can also keep track of the times you might have woken up in the night. You view your sleep comparison charts in the Health app on your iPhone and the Sleep app on your Apple Watch. 

How to set up Sleep Stage Tracking on Apple Watch

To track your sleep stages, wear your Apple Watch to bed and make sure the Sleep Focus is turned on (either manually or by establishing a sleep schedule.)

You don’t need to set up a sleep schedule to track your sleep stages, but you do need to turn on your Sleep Focus!

  1. Update your watch and iPhone so they run the latest watchOS and iOS versions (at a minimum, you must run watchOS 9 and iOS 16.)
  2. Open the Sleep app on your Apple Watch and follow the onscreen guide to set it up if it’s the first time. Or open the Health app on iPhone, tap Browse, tap Sleep, then tap Get Started (under Set Up Sleep). 
  3. Create a Bedtime and Wake Up schedule OR turn manually on the Sleep Focus (in Control Center) each night before you go to bed. To track sleep stages, the Sleep Focus must be on!
    1. When you create a schedule, your watch automatically turns on the Sleep Focus
    2. When your Sleep Focus is active, the bed icon appears at the top of the watch face, next to the time in apps and Control Center. Apple Watch Sleep Focus in Control Center
  4. Make sure your watch tracks sleep by going to Settings > Sleep and toggling on Sleep Tracking. Sleep tracking settings on Apple Watch
    1. This feature must be on so your Apple Watch can track your sleep and sleep stages.

Now all you need to do is hit the sack if you turned on a sleep schedule. Your watch automatically turns your sleep focus on and off according to your schedule.

If you didn’t set a sleep schedule, swipe up Control Center before you go to bed, hit the Focus button (DND), and tap Sleep! Just remember to turn Sleep off when you wake up.

To learn more about setting up sleep tracking on Apple Watch, see this article How to turn on Sleep Mode on your Apple Watch using watchOS8+.

How to interpret Apple’s sleep datatrack sleep stages apple watch

Apple breaks down your sleep data into the four sleep stages: Awake, REM, Core, and Deep.

The chart in the Health iPhone app or Sleep Apple Watch app shows these four stages and how long you were in each phase.

Once your Sleep and Health apps gather enough data, you’ll be able to see your sleep cycle trends over time in the daily, weekly, monthly, and 6-month charts. new sleep stages data apple

Each stage has a different color assigned to it.

  1. Awake has red.
  2. REM has a teal blue shade.
  3. Core has a bright cobalt blue.
  4. Deep has a purple shade.

Next to each stage, you see how much time you spent in each sleep phase. Scroll further down, and Apple gives you the time amount and even the percentage below it. iPhone Apple Health app sleep stage percentage

Tap the tabs (Stages, Amount, Comparisons) in the middle for other metrics, including your sleep goal, time in bed, time asleep, sleeping heart rate, respiratory rate, and for some Apple Watch models (Series 8+ and Ultra), your wrist temperature while sleeping. iPhone Apple Health app sleep comparison data

What’s different about the Sleep app?

Apple’s previous method of collecting sleep data in watchOS 8 and below did not offer a lot of information, but with watchOS 9+ and iOS 16+, you now see a breakdown of your sleep cycle in sleep stages.

In watchOS 8, you see the average time slept and awake. In watchOS 9, the Sleep app calculates time slept and awake along with a breakdown of time slept into three stages (REM, Deep, and Core.)

Here’s how the Sleep app is different for me–it only tracked time asleep and time awake before the watchOS 9/iOS 16 updates. But after the update, it now tracks all my sleep stages. So I see more variation in the sleep data chart below.

apple sleep trends

Apple Watch and Health app not showing sleep stages?

If you aren’t seeing any sleep tracking information, likely, you did not turn on the Sleep Focus.

You can manually turn this on each night before bed via your watch’s Control Center’s Focus settings (formerly Do Not Disturb) and tapping the Sleep option. Apple Watch control center sleep mode on as the Focus and Do Not Disturb mode

If you use a schedule, check your iPhone’s Health app

  1. Open the Health app and choose Browse > Sleep.
  2. Scroll down and select Full Schedule & Options. Full Sleep Schedule in iPhone Health app
  3. Toggle on Use Schedule for Sleep Focus and Sleep Schedule. iPhone Health app Sleep schedule option to use sleep focus
  4. Some folks found they needed to delete their current Sleep Focus and create a new one to get sleep tracking to work correctly.
    1. Open the Settings app on your Apple Watch, tap Focus, then tap Sleep Focus. Tap a schedule, scroll down, then tap Delete.
    2. If you cannot delete your sleep focus on your watch, open your iPhone Settings app > Focus > Sleep Focus. Scroll down and tap Delete Focus.

It’s also possible that Sleep Tracking is off on your watch. To check, open the Settings app > Sleep and toggle on Sleep Tracking. Sleep app settings for sleep tracking Apple Watch

Final thoughts

Before Apple introduced their new sleep stages feature, sleep tracking on your iPhone and Apple Watch was rather lackluster. Many users sought third-party apps like AutoSleep, Pillow, and more to track their sleep.

Now, Apple has FINALLY stepped up their game, and they are giving us what we’ve wanted for so long. Update your iOS and watchOS now to access this new and exciting feature!

Note: you will need an Apple Watch that can update watchOS 9 to access the new sleep cycle tracking. Apple Watches that are Series 4 and higher can take the latest update.

What do you think of Apple’s new sleep stage tracking feature? Let us know!

I'm a content writer with a passion for all things lifestyle having earned my Bachelor of Science in journalism from St. John's University. I was born and raised in Southern California. My Apple Watch never leaves my wrist, but I also adore Fitbit. I love all things health tech, including fitness and self-care apps. When I'm not writing, I enjoy traveling, reading, and drinking iced coffee!

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