3 ms·

So it watches your bloodpressure or something? I figured it was the jerking-around. Maybe it looked to the watch like she had fallen down.

• BjoernKW 7y ago
  It watches the heartbeat, probably arrhythmias specifically. You can't monitor blood pressure with just a watch. You need a blood pressure cuff for that.
  • swayvil 7y ago
    Does it watch heartbeat via the gyroscope? If so then that's a darn sensitive gyroscope.
    • defap 7y ago
      Via an optical sensor that can perform photoplethysmography.
  • Symmetry 7y ago
    The Apple watch can look at blood oxygen levels too which might have been what triggered the alert.