I'm late to the party. I recently bought a Marvel Vivoactive 4s watch. I've had a Vivoactive 4 watch for a few years now and I feel like the heart rate tracks reasonably well. The new Marvel watch seems to be hugely off when tracking heart rate during activity.
For instance, I can take my pulse during an activity and my hr will be around 100bpm, the watch is tracking 50bpm. With no variation for increased cardiac load (read "sprinting uphill" or "increased paddling speed while kayaking").
How can I calibrate the watch to pick up on a more accurate hr?
