How does Apple Watch track sleep?

[PeaceLoveAndPizza]

This is a topic that has been discussed quite often with questions on the accuracy of Apple Watch tracking sleep stages and how it compares to medical grade equipment. 

There is a lad on YouTube known as “The Quantified Scientist” (aka Rob ter Horst, PhD) who does scientific studies into sleep. He has released a video explaining how the Apple Watch tracks sleep and sleep stages, plus a comparison to the Oura ring and medical grade sleep tracking equipment.

I will not give away the punchline, so if this is a topic you find interesting watch the video here.

https://youtu.be/niLuR68YleI?si=vwt3e_yyfBRjfSYl

If this does not interest you, here is a video of Keanu Reeves playing with puppies whilst answering fan questions.

https://youtu.be/rOqUiXhECos?si=2BRS-zvVLUK9AzIu

Happy Caturday!

[joeblough]

that is a great video, thank you for that. in fact he alluded to a couple of devices - the dreem 2 and the zmax. i think the dreem is no longer available but the zmax could be very interesting as an in-home EEG-based PSG. of course, it's not at all cheap. in my case i really would like to see an EEG-based PSG while wearing the CPAP as i suspect i have some other issue besides SDB.

i happened to run into one of the guys who did a lot of the work on the newer apple watch sleep tracking, but at the time i didn't know who he was. one question for him would be if they intend to try to help people with sleep disorders get better ideas of their sleep staging. i know apple published a white paper, and looking at it now they did include people with PLM and OSA in their study, so it seems like the AW might be able to stage someone with OSA at least.

i wonder where the guy in the video got the data for tracker accuracy for people with sleep disorders. i do know that how i feel in the morning never seems to have any correlation with what my apple watch 8 says about the amount of deep sleep i had or how many awakenings it detected.