How accurate are wrist-based HR monitors?


On the bike I use a Tickr HR strap and wear a Garmin Vivoactive 3 ‘watch’.

Today on the trainer doing thesthold work the strap said 176 while the Garmin optical said 88, and never rose above 116. :rofl: The optical HR figures for me on the bike are just nonsense, and so I make no use of them whatsoever.

When running, the Garmin optical has been better, but only up to a point, frequently under-reading, sometimes dramatically. Sat around, the figures from the Garmin optical seem correct.

But for my partner, the same Garmin optical wrist-based seems to work fine for her when running, every time.


My Vivoactive 3 tracks my HR with less obvious errors than a Wahoo Tickr chest strap, even up to a HR of 201. But, my skin color is quite light, I have low body fat, little hair and visible veins. Overall, I prefer VA3 over Wahoo Tickr.


My WHOOP band tracks perfectly with my chest strap both on and off the bike. I’ve been very happy with the performance, thus far! As an alternative, they also have a bicep band for their sensor. Totally worth checking out - for multiple reasons!


That’s funny, because your physical characteristics describes me to a tee!

Yet totally opposite results :laughing:


My experience with Garman FR235 bulleted for easy consumption… I am somewhat fair skinned with not much arm hair, low body fat:

  • Not accurate enough for consistent Hr based zone training in running or cycling. I would use a strap (love my Wahoo Tickr) for this.
  • Pretty good for resting HR.
  • Accurate enough for monitoring HR as a secondary metric when running. I use pace or power as primary effort metrics when running. I don’t wear it when cycling very much anymore.
  • Accurate enough for some pacing when running once you’re dialed in to RPE with pace or power. I didn’t wear my HR strap for my recent 70.3 A race (who does)? The run featured about 6 miles of sand running where Stryd power wasn’t useable and pace wasn’t a consistent metric due to the inconsistent pack of the sand. Therefore, HR and RPE were my best bets. I had the 235 on my wrist fairly snug, and it did a good enough job tracking my HR to give me a good idea of my pacing effort for those sand sections.

Bottom line: my 235 is accurate enough for occasional HR use, HR tracking for info, or as a backup, and probably accurate enough for most people’s exercise tracking, but I would recommend a HR strap to any serious racer who wants to use HR as a primary training metric or training zone basis.