Quality sleep is a vital component of overall health and well-being, with research showing that getting enough quality sleep is essential for physical and mental health. In scientific terms, core sleep refers to the deep, restorative sleep that occurs during the first half of the night when the body enters into its most restful sleep stages, such as slow-wave sleep and REM sleep.

Science vs Pop Culture

On the other hand, when it comes to the Apple Watch, core sleep is a feature that tracks your sleep patterns and provides insights into your overall sleep quality. The Apple Watch uses a combination of sensors and algorithms to monitor your movement during sleep, helping to determine the amount of time spent in deep sleep, light sleep, and REM sleep.

While core sleep in scientific terms refers to the most important and restorative stages of sleep, the Apple Watch’s interpretation does necessarily align perfectly with this definition. The Apple Watch provides a more general overview of your sleep patterns and may not be as precise in identifying specific sleep stages. In fact, Apple’s core sleep refers to “light” sleep — the first two stages of sleep — but were worried that this would sound like an unimportant stage of sleep, so they rebranded it “core sleep.” 

Sleep Tracker Limitations 

Overall, while the Apple Watch (and other sleep trackers) can provide valuable insights into your sleep patterns and help you track your overall sleep quality, it is important to remember that core sleep, as defined by science, represents the deep, restorative sleep that is crucial for physical and mental health. By incorporating both scientific knowledge of sleep and the data provided by the Apple Watch, you can gain a more comprehensive understanding of your sleep habits and make informed decisions to improve your overall well-being.