While holding the watch in the air, the heart rate glance provides a heart rate that jumps around.
How is this possible? The sensor on the back is pressed up against nothing.
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While holding the watch in the air, the heart rate glance provides a heart rate that jumps around.
How is this possible? The sensor on the back is pressed up against nothing.
Best Answer
The heart rate sensor on the Apple Watch works by processing signal from two photodiodes. It is designed to have two green LED reflect from the wrist, but readings are likely due to picking up light reflected off another surface.
From Apple: