@SimonRJ wrote:
Sorry, but to suggest that moisture will improve the accuracy is just wrong. A quick review of several articles regarding optically based sensors, including one from the MIT weekly technical journal, suggests that sweat actually inhibits the accuracy of these sensors. None of them equate the presence of sweat or water to improved accuracy. The first few minutes of inaccuracies subside due to body temperature increases, not sweat or moisture.
What the articles do say that seem concurrent to observations made here is that the accuracy improves as temperature increases, especially during exercise, due to blood vessels moving closer to the skin surface to aid in body cooling - hence the sensor being able to get a better reading.
This seems to make the most sense, based on what I've experienced. At first the HR reading was wildly high for everything except resting. I then tightened the band, and this seemed to take care of the inaccuracies while walking or cycling. However, the HR reading still immediately spikes to around 180 when I start running. Wetting my wrist makes no difference. However, about 4-5 miles into a run the HR reading will suddenly drop to what I would expect it to be, and remain that way for the remainder of the run.
