N3 (deep or slow-wave sleep). REM sleep is distinct from non- REM sleep in three main ways: the namesake rapid eye movements, changes in respiration pattern...
https://www.apple.com/jp/healthcare/docs/site/Estimating_Sleep_Stages_from_Apple_Watch_Sept_2023.pdf
and processes because of the challenges related to compiling a comprehensive catalog of PFAS use, identifying and developing non-PFAS alternatives that can ...
https://www.apple.com/jp/environment/pdf/Apple_PFAS_Commitment_November-2022.pdf