Apple Watch: Accurate Deep Sleep Tracking?

The Apple Watch is a popular device for tracking sleep, with wearers able to monitor their sleep data through the Health app on their iPhone. The watch uses signals from its built-in accelerometer and heart rate sensor to detect movement and keep a check on sleep stages. While it is considered one of the most accurate wearable devices for sleep tracking, there are questions over its ability to accurately detect deep sleep.

So, how does it work?

Apple Watch deep sleep tracking accuracy

The Apple Watch uses signals from the built-in accelerometer and heart rate sensor to detect movement and keep a check on sleep stages. It can track the time spent in different sleep stages: REM (dreaming), Core (light sleep), and Deep Sleep (a restorative phase). The watch also needs to be unlocked to get sleep tracking, and it is recommended to be worn tightly on the wrist for accurate tracking.

Apple Watch users have reported that the device has some of the best sleep-tracking capabilities for any wearable, likely due to Apple's extensive research and large-scale sleep studies. However, it is not perfect, especially for deep sleep tracking, which is difficult to accurately detect. Users have reported inconsistencies in deep sleep tracking between the Apple Watch and other devices and apps.

To get the most accurate results when wearing your Apple Watch to track sleep, it is recommended to enable Charging Reminders and ensure the watch is charged to at least 30% before bed. Additionally, the watch should be worn for at least one hour each night, and it should fit comfortably and securely on the wrist.

The Sleep app on the Apple Watch provides detailed sleep data, including the time spent in each sleep stage, heart rate, and respiratory rate. The Health app on the iPhone can also be used to view sleep history and set sleep goals and schedules.

Third-party sleep tracking apps

While the Apple Watch does provide some sleep tracking features, third-party sleep tracking apps offer more detailed data and insights. These apps can integrate with the Apple Health app, providing a comprehensive overview of your sleep data.

One of the most popular third-party sleep tracking apps for Apple Watch is AutoSleep. AutoSleep offers extensive data and analysis, allowing users to gain valuable insights into their sleep patterns and make informed decisions about their sleep health. The app automatically tracks your sleep, with no buttons to press, and even the Watch app is optional. It also respects user privacy, with no user analytics tracking, advertising plugins, or data uploads. AutoSleep integrates with the Sleep Stages from the Apple Sleep app, allowing users to view their sleep data in both AutoSleep and the Apple Sleep app.

Another highly-regarded third-party sleep tracking app is Sleep Cycle. Some users have found that Sleep Cycle provides a more accurate representation of their sleep patterns, particularly in terms of deep sleep, compared to the Apple Watch's native sleep tracking.

Other notable third-party sleep tracking apps for Apple Watch include Pillow, which offers a smart alarm feature to wake you up during your lightest sleep phase, and SleepWatch, which provides detailed sleep analysis and personalized sleep improvement tips.

It's important to note that while these third-party apps offer more data and insights, they may not always provide perfectly accurate results, especially when it comes to deep sleep detection. Additionally, some apps may require a subscription or in-app purchases.

Setting up sleep tracking

Step 1: Charge your Apple Watch

Before you go to bed, ensure your Apple Watch is charged to at least 30%. This is important because if the battery dies while you're sleeping, the sleep tracking will stop. You can set up charging reminders to avoid this issue.

Step 2: Wear your Apple Watch to bed

To track your sleep, you need to wear your Apple Watch to bed. Make sure it fits comfortably on your wrist. A loose fit may result in the accelerometer registering too much movement during your natural sleep, affecting the accuracy of the tracking.

Step 3: Open the Sleep app

When you wake up, open the Sleep app on your Apple Watch or iPhone. You can also ask Siri, "How much did I sleep last night?" on supported models.

Step 4: View your sleep data

In the Sleep app, you can see the amount of sleep you got, the time spent in each sleep stage (REM, Core, and Deep), and your sleep average over the last 14 days. You can also access this information through the Health app on your iPhone.

Step 5: Adjust settings and create a sleep schedule

You can adjust various settings and create a personalised sleep schedule. Here are some options:

• Set a sleep goal: Decide on the number of hours of sleep you want to aim for each night.
• Turn on Sleep Focus: This feature limits distractions before bedtime and protects your sleep after you're in bed.
• Set a wind-down time: Determine when you want to start winding down before bed. This can trigger Sleep Focus and bedtime reminders.
• Set your wake-up time and alarm preferences: Customise your alarm sound and choose whether you want your Apple Watch to wake you up in the morning.
• Create multiple sleep schedules: You can create different schedules for weekdays and weekends, for example.

Step 6: Explore third-party sleep tracking apps

While the built-in Apple Watch sleep tracker is a good option, you may want to explore third-party sleep tracking apps for more advanced features. These apps can offer additional insights and a more comprehensive understanding of your sleep patterns.

Remember, tracking your sleep is a great way to gain insights into your sleep habits and make improvements for better overall health.

Sleep tracking with other devices

Sleep tracking is available on watchOS 8 or later. To receive sleep data, you must wear your Apple Watch for at least 1 hour every night. If you don't wear your Apple Watch to sleep, your graph might not show any data. The Apple Watch can help track your breathing rate as you sleep, which can give you greater insight into your overall health.

If you're looking for other devices to track your sleep, there are many options available. Firstly, the Ultrahuman Ring Air has been praised for its accuracy and the valuable advice provided in the accompanying app. The ring has a medical-grade temperature sensor, a PPG (photoplethysmography) sensor, and a motion-sensing IMU (inertial measurement unit). Another option is the Whoop band, which provides sleep data through the Whoop smartphone app. The app includes written explanations to clarify the data presented and allows you to analyze your daily, weekly, and monthly sleep patterns.

Garmin's fitness trackers also offer sleep tracking to some extent, with watches like the Epix Pro offering advanced sleep monitoring features, including the ability to track sleep stages, blood oxygen saturation, respiration, and restlessness. Additionally, Fitbit devices have been found to detect sleep onset with high accuracy and satisfactorily track sleep cycles.

Other popular sleep tracking devices include the Pixel Watch, Galaxy Watch 5, Amazon Halo Rise, Oura Ring, and Withings Sleep Mat. These devices offer varying levels of accuracy in measuring sleep stages, sleep efficiency, and sleep latency. It's important to note that while these devices can provide valuable insights, they don't directly measure sleep, and exact data would require a medical sleep study.

Sleep tracking limitations

Sleep tracking on the Apple Watch has certain limitations. Firstly, it is important to note that the watch does not automatically monitor sleep; users must manually enable sleep tracking and set a schedule. Additionally, the watch must be worn for at least one hour each night to receive sleep data, and the battery must be charged to at least 30% before bed. If the watch battery dies or is not worn, it will not track sleep data. The accuracy of the data also depends on the fit of the watch; if it is too loose, the accelerometer may register too much movement during sleep, affecting the data.

While the Apple Watch can provide insights into sleep patterns and durations, it may not accurately detect specific sleep stages, particularly REM and deep sleep. The watch relies on heart rate, movement, and other measurements to infer sleep stages, which may not always be reliable. The accuracy of sleep data can vary between individuals, and other factors such as wrist size and natural sleep movement can also impact the tracking.

Furthermore, the Apple Watch is not a medical device, and its respiratory rate measurements are not intended for medical use. Although it can detect parameters like heart rate, blood oxygen levels, and respiratory rate, it cannot completely detect or diagnose sleep disorders such as sleep apnea.

To ensure the most accurate results, users should follow the setup instructions, including enabling sleep tracking, setting a schedule, and ensuring a comfortable fit. It is also important to note that sleep tracking data should be used as a reference, and if individuals have concerns about their sleep or suspect a sleep disorder, they should consult a healthcare professional.

Frequently asked questions