A close friend of mine recently asked me why we did not add optical based heart rate sensors to The Socialite Collection - www.wisewear.com. Given that both our CTO and I both have PhDs in Biomedical Optics, we explored this avenue. The truth is that after conducting extensive research tests, we found it is incredibly difficult to use optical sensors for accurate heart rate measurements from the wrist. Wrist worn wearables can provide accurate measurements of resting heart rate; however, the good old EKG-based chest strap is the only way to go for intense workouts. For those of you interested in staying in the orange zone during HIIT-like workouts, I recommend you stick with the EKG-based chest strap.
The Good news is that wrist worn wearables can provide an accurate measure of resting heart rate.
Several other recent studies also support these findings.