article_snippet.sent: This is because the heart sensor reads a pulse by measuring light absorption though the skin - a process called photoplethysmography. '
article_snippet.sent: This technology, while difficult to pronounce, is based on a very simple fact: Blood is red because This technology reflects red light and absorbs green light, Apple wrote on Applesupport page. '
article_snippet.sent: When your heart beats, the blood flow in your wrist - and the green light absorption - is greater.
article_snippet.sent: This is because the heart sensor reads a pulse by measuring light absorption though the skin - a process called photoplethysmography. '
article_snippet.sent: This technology, while difficult to pronounce, is based on a very simple fact: Blood is red because This technology reflects red light and absorbs green light, Apple writes on Apple support page. '
article_snippet.sent: When your heart beats, the blood flow in your wrist - and the green light absorption - is greater.
highlights_snippet.sent: Sensor takes readings by measuring light absorption though the skin .
  