This is me quickly mowing the lawn, out of breath. The watch thinks my heart rate is between 90-110. For the last 10 minutes, I have started a Cardio activity and this shows that my real heart rate is 140. I wonder why the heart rate is shown at all when moving if it is so inaccurate... It could just show '---' like the stress level.
I would rather charge my watch every two days but get accurate information.
