WatchOS 7 has added a "sleep tracking function", which is a long-rumored function, but after trying it out, maybe I will understand why Apple Watch introduced this function so late.
1. When will I charge my Apple Watch while sleeping?
Nowadays, most people also charge their Apple Watch while they are sleeping. Basically, Apple Watch can be used for one day. However, if you sleep for 8 hours, it is estimated that the power of Apple Watch will drop by at least 2% per hour. Even if your Apple Watch is 100% power before going to bed, there will only be about 80% of the power left after you wake up.
2. Is it not comfortable to wear a watch during sleep?
Do you wear a watch to sleep on weekdays? Before Smart Watch, I believe you would not? It is still acceptable to use some lightweight strap styles, but it is not suitable to use steel straps.
3. Sleep data is not detailed enough
In terms of sleep data, watchOS only provides heartbeat changes and sleep time data. I want to know whether I have entered deep sleep or shallow sleep.
Summary: You can count sleep time without Apple Watch
Why must I use Apple Watch to count sleep time? Unless you want to know how your heartbeat changes when you sleep. Otherwise, if you only need to know how many minutes you have slept, it is better to use the AutoSleep App to calculate your sleep time based on the iPhone usage.