How accurate is apple watch sleep tracker?

I just bought an Apple Watch and am trying to use the sleep tracker, but it seems a bit complicated. Is it really accurate in detecting when we wake up in the middle of the night, or does it just guess based on arm movement?

In my experience, the Apple Watch is highly accurate for sleep duration and wake-up times. However, I noticed it sometimes registers me as sleeping when I am just lying in bed reading a book quietly.

It is a nice modern tool to monitor your rest, but do not let its numbers worry your mind. True rest comes from a peaceful heart and meditation before bed. Take care of your inner peace, and sleep will naturally improve.

Honestly, it's pretty spot on for tracking when I sleep and wake up. I compared it with other trackers and the Apple Watch easily handles the sleep stages best. It's great for daily tracking, just charge it before bed.

At my age, my back tells me how I slept much better than any Apple Watch ever can! But yes, the watch is decent for keeping track of your sleep hours, even if it constantly reminds me of how little rest I actually get.