The study seems small. Really small. 125ish nights worth of data?. The results came back very comparable from all devices.

It's almost like when someone falls asleep it's pretty obvious.

I wish this study did a few things, like get more into depth on the sleep cycle. I own an oura 2. I perused the study, but didn't read it word for word start to finish, so I missed whether it was an oura 1, 2 or 3.

How accurate can these devices tell what stage of sleep the body is in? That's a more relevant question for 2023