The new watchOS 9 brings new Sleep stages tracking on compatible Apple Watches. Before the public release of the update, YouTuber @The Quantified Scientist took advantage of watchOS 9 beta to test how accurately the Apple Watch tracks Sleep stages and found that the results were very close, nearly identical to an EEG device.
18 nights of sleep data from Apple Watch delivered, almost, the same results as an EEG device
An electroencephalogram or EEG device is exclusively designed to measure the electrical activity in the brain. As brain cells communicate through electrical impulses and remain active even during sleep, the small, metal discs or electrodes of an EEG device are attached to the scalp to record brain activity.
On watchOS 9, an Apple Watch uses machine learning and a new algorithm to take data from users’ heart rate and movement to track how much time users spent in REM, Core, and Deep Sleep stages of sleep, along with the time they might have woken up. Integrated with the iOS Health app, users can also track their sleep over time with heart rate and respiratory rate metrics.
For the test, YouTuber tracked sleep stages on Apple Watch Series 7 on watchOS 9 beta and an EEG device for 18 nights and found that the results were mostly the same on both devices proving that Apple Watch is a reliable sleep-tracking device when most smartwatches are not.
Sleep stages tracking allows users to determine the quality of their sleep. They can analyze the periods of time when they are sleeping less deeply and made changes to improve it. A good night’s sleep is very beneficial for a person’s level of attention and concentration, memory, health, heart condition, immune system, and others. aspects.