Over 50 brands worldwide offer products that are compatible with HomeKit and your Apple devices — with more and more on the way.
such as the American Academy of Sleep Medicine (AASM),1 the Centers for Disease Control and Prevention (CDC),2 and the American Heart Association (AHA)3 all...
https://www.apple.com/healthcare/docs/site/Estimating_Sleep_Stages_from_Apple_Watch_Sept_2023.pdf