article_snippet.sent: Apple Watch uses green LED lights paired with light‑sensitive photodiodes to detect the amount of blood flowing through your wrist at any given moment. '
article_snippet.sent: By flashing it LED lights hundreds of times per second, Apple Watch can calculate the number of times the heart beats each minute - your heart rate.'
article_snippet.sent: Apple Watch uses green LED lights paired with light‑sensitive photodiodes to detect the amount of blood flowing through your wrist at any given moment. '
article_snippet.sent: By flashing it LED lights hundreds of times per second, Apple Watch can calculate the number of times the heart beats each minute - your heart rate.