Apple's Sleep Tracker: A Feature To Dream About

Apple Watch offers a wide range of functions, including sleep tracking. The Sleep app is designed to help users meet their sleep goals, including getting enough sleep, getting to bed on time, and creating a pre-bedtime routine. The app includes bedtime reminders, wake-up alarms, sleep tracking, Sleep Focus, Wind Down, and a view of sleep trends over time. However, it is important to note that the Apple Watch has shorter battery life than most sleep trackers, which may impact its ability to track sleep. Additionally, the accuracy of sleep staging data may be lower compared to laboratory sleep studies.

The Sleep app

To use the Sleep app, you need to set up a sleep schedule on your iPhone or Apple Watch. You can set a sleep goal (how many hours of sleep you want to get) and a sleep schedule to help you meet your sleep goals and get to bed on time. You can also set up general settings, such as whether to turn on Sleep Focus, which limits distractions before you go to bed and protects your sleep after you're in bed.

When Sleep Tracking is turned on, your Apple Watch tracks your sleep and adds sleep data to the Health app on your iPhone. It uses data from the accelerometer and heart rate sensor to determine what stage of sleep you are in. It can estimate the time spent in each sleep stage—REM, Core, and Deep—as well as when you might have woken up.

Sleep tracking accuracy

The Apple Watch has a built-in Sleep app that can track your sleep. The watch uses data from the accelerometer and heart rate sensor to determine what stage of sleep you are in. The Sleep app can also help you meet your sleep goals by creating sleep schedules, limiting distractions before bedtime, and protecting your sleep after you're in bed.

To use the Sleep app, your Apple Watch must be running watchOS 7 or later on a Series 3 or newer, SE, or Ultra. You'll also need an iPhone 6s or later running iOS 14 or higher. Before it can track your sleep, your Apple Watch must be set up accordingly. In the Watch app on your phone, open My Watch and select Sleep. Tap "Use this Watch for Sleep" to enable the feature. Make sure the switches next to Track Sleep with Apple Watch and Charging Reminders have been turned on.

Third-party apps can also be used to track your sleep. These apps can be downloaded directly onto your Apple Watch through the App Store. Examples of third-party sleep-tracking apps include AutoSleep Track Sleep, SleepBot, and SleepRoutine.

While sleep trackers can provide a lot of information about your sleep habits, it's important to note that they don't directly measure sleep. Instead, they often measure inactivity as a surrogate for estimating sleep. Most sleep-tracking devices make some guesstimates as to how much you're actually sleeping. For exact data about your sleep habits, you would need to undergo a medical sleep study that monitors brain waves to analyze the stages of sleep.

However, studies have shown that consumer sleep-tracking devices perform as well as, or even better than, actigraphy. Actigraphy is a sleep test based on data collected from a wrist-worn device that is only available from a medical professional or through a lab-based study. The accuracy of consumer sleep trackers compared to actigraphy means that wearers can expect data that is on par with some research-grade sleep-tracking devices.

Sleep tracking with third-party apps

Apple does have a sleep-tracking app and a built-in sleep tracker for its Apple Watch. However, if you want to explore other options, there are numerous third-party sleep-tracking apps available. These apps can be easily downloaded from the App Store directly on your Apple Watch, as long as it is running watchOS 6 or higher.

To download a third-party sleep-tracking app, open the Watch app on your iPhone and tap 'Discover'. Then, select 'Explore Watch Apps' and tap the search icon. You can then type a phrase such as "sleep trackers" or search for a specific app by name. Once you find the app you want, you can tap 'Get' to install any free apps or select the price button to purchase it.

Some third-party sleep-tracking apps include SleepScore, SleepCycle, and Pillow. SleepScore stores user information in controlled facilities, rather than third-party servers or databases, and is transparent about its science. SleepCycle, on the other hand, uses sound-sensing technology and your phone's microphone to detect the sounds you make when moving to assess your sleep. This means that you do not need to place your phone directly under your mattress, and it can be placed on a nightstand instead. Pillow was one of the apps tested in a 2023 joint study with Stanford and Seoul National University Bundang Hospital, which compared 11 sleep trackers against PSG.

Other sleep apps, such as Calm, are designed to help you relax and decrease stress and anxiety, a common cause of sleep disturbances. The app features soundscapes, music playlists, and celebrity sleep stories to help you fall asleep. While some apps focus on helping you fall asleep, others track the duration and quality of your sleep, providing valuable data. These apps use inputs such as sound, heart rate, bedtime, and wake time to give you a snapshot of your sleep duration and quality. They can also provide you with a "sleep score" and create graphs that show changes over time.

Battery life

The Apple Watch is a powerful sleep tracker. However, it has one significant shortcoming: its battery life. Most Apple Watches deliver around 18 hours of battery life on a single charge. This means that if you wear it all day, you will likely need to charge it around the time you want to start tracking your sleep. If the battery dies while you are asleep, the sleep tracking will stop. Therefore, if you want to use your watch as a sleep tracker, you will need to set aside some time during the day to charge it.

Apple has made some improvements in recent versions of the watch with sleep tracking in mind. These include a low-power conservation mode, charging reminders, and an upgraded cable that improves charging speed (but not overall battery life) on watches from the Series 7 onwards. The Apple Watch Ultra has a longer battery life of 36 hours, which can be useful for sleep tracking.

To set up a charging reminder, go to the Apple Watch app on your iPhone, tap the Sleep tab, then toggle the slider under Charging Reminders. With this turned on, your watch will send you a notification if your watch's battery is less than 30% charged an hour before your scheduled bedtime.

If you feel that the built-in Sleep app is not robust or flexible enough, you can use a third-party app to track your sleep. To add a third-party app, open the Watch app on your phone, tap Discover, select Explore Watch Apps, and tap the search icon. Type a phrase such as "sleep trackers" or enter the name of a specific app. Once you find one, tap Get on any free app to install it or select the price button to buy it.

Sleep tracking data

Another way to collect sleep tracking data is through dedicated sleep sensors or smart mattresses, which can track movement, heart rate, and respiratory rate. This data can be used to determine how long it takes the user to fall asleep and how much time they spend in each sleep cycle. Smart mattresses can also include heating and cooling modes and other premium features. One benefit of dedicated sleep trackers is accuracy, as they don't have to be worn on the body and don't need to be charged.

Additionally, some smartwatches, like the Apple Watch, offer built-in sleep tracking capabilities. The watch uses data from its accelerometer and heart rate sensor to determine what stage of sleep the user is in. The watch can also track the user's breathing rate during sleep, providing insights into their overall health. To enable sleep tracking on the Apple Watch, users need to ensure their device is running watchOS 7 or later and set up the feature in the Watch app.

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