From another website, my experience comparing HR monitors.
People have wondered what to use for a heart rate monitor/activity tracker, so I decided to see. I have the Apple Watch, series one, and bought a Garmin vivoSmart HR+, and obviously the Peloton HR system.
So yesterday, they were both within 1 or 2 beats of each other. Really. The Apple Watch takes a couple of seconds to get a reading, but after the wait, the numbers were the same. It did that all through the ride (
Steven T. Little Friday endurance ride), and it was good.
So today's ride, Everything starts out womped. The Garmin is showing faster, then slower, then really slow. The two showed 119, and the Garmin showed 79, and then 70. Interesting.
After the ride, while I was cooling down, I checked the Garmin. It was at 150. Then 160, then 170, then 180. Trying not to panic, I checked my heart rate manually, and it was within what the other two said. Finally the Garmin came down but it was still higher than the other two. Even now the Garmin is 4 to 6 beats above the Apple Watch. I don't know what happened between yesterday and today, but the Garmin isn't very accurate, so far. I'm disappointed.
I had the Garmin, and the Apple Watch in the same position on the same wrist. Odd that it was so much worse today. But that has been my experience, so far. I'll give it a few more days to see how it goes, but the Apple Watch, which I've ripped before, isn't that far off. Just slow to catch up...