If you read this blog you know I do not like optical HR monitors (see: Wrist/optical HR monitors are worth +10 BMP). However, it was time to update my aging watch and the Garmin Forerunner 935 was the obvious choice. Check out DC Rainmakers full review here: Garmin Forerunner 935 In-Depth Review. It’s essentially the best Garmin ever made. But I’m not here to tell you about the watch, I’m here to tell you about it’s optical HR monitor. The best way to do this is to check out the graphs below. You can immediately see the flaws in the Garmin Forerunner 935’s optical HR monitor when comparing it to a chest strap.
Wrist/optical HR monitor (Garmin Forerunner 935):
Chest strap HR monitor (Garmin Premium):
Granted, the workout I did with the 935 is a different workout than I did with the chest strap, but that’s not the point. A HR monitor should track smoothly with pace assuming you are in top physical condition and on flat ground (yes I know environmental factors and level of fatigue can alter HR). The 935 does a much better job of this, but it’s still not where it needs to be.
- A million times better than the 235
- All day HR is also much improved and is now measured every 1 to 2 seconds
- Doesn’t adapt quickly enough during intervals
- Still not as accurate as a chest strap
- None of Garmin’s advanced metrics or the LT test work with the optical HR monitor
No, I wasn’t wrong. But optional HR monitors are improving quickly. I’m looking forward to the day I can ditch my chest strap for good. For now I’ll use the 935 HR monitor for casual runs and the chest strap for hard workouts.