This discussion has been locked.

You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Wrist-based HR reading inaccurate. Any tips or ideas?

I just got a new Forerunner 45S and did my first run yesterday. I found that the wrist-based HR reading seemed suspiciously low. (My RPE felt quite a bit higher than the HR showed.) So I ran back home and got my chest strap, connected it to my phone and took off running again. Sure enough, the HR reading from my watch was about 20-25 beats lower than what my phone was showing.

Are there ways to ensure a more accurate HR reading from wrist, i.e. tips on wearing the watch? Or is this just a nuance of wrist-based HR measurement and chest-based is always going to be more precise? I was hesitant to get this watch for this very reason, but liked the idea of not having to wear a chest strap.

I'm sure that I'm not the first one to have this question, so please let me know if there are other resources that better explain this. I've read the user manual and Garmin's statement on wrist-based HR measurement, and both are somewhat vague. But based on my experience so far, I don't see this as a reliable method for measuring HR.

0 lytleric over 5 years ago

So a little bit of Google research and I mostly answered my question: Wrist-based heart rate should not be assumed to be accurate, especially during intense physical activity. During rest, it can be accurate. But if I want accuracy, I should stick to a chest strap during physical exercise.

https://trailrunnermag.com/training/why-you-should-be-skeptical-about-your-wrist-based-heart-rate.html

Disappointing, but not surprising, I suppose.

0 JacekThomann over 5 years ago

Hi, I am doing right now a review of the unit and I've noticed that if you move the watch higher thru direction of the elbow you might get better reading. I've attached some gprahs which shows the accuracy of the unit.

I think it's quite accurate.

0 lytleric over 5 years ago in reply to JacekThomann

Yes, I've also done further research since posting my question and found that position and tightness on the wrist are both critical to getting an accurate heart rate reading, i.e. it needs to be further up the wrist (away from the hand) and it needs to be quite tight against the skin. Unfortunately, both of those are uncomfortable for me while running! I like to wear the watch closer to my hand, which keeps it from getting covered by my sleeve (if wearing long sleeves or a jacket), and I don't like it to be super-snug either, just tight enough that it doesn't move around.

So I guess I am better off sticking with the chest strap for now.

0 4221014 over 5 years ago

Interesting reading!

@JacekThomann, do you mind sharing your review? :)

0 JacekThomann over 5 years ago in reply to 4221014

Hi, well 45 isn't ready yet it will be at the end of the week but you can find some comparison of the new optical sensor in the 945 review.
You can see it here, http://www.goultra.pl/recenzja-garmin-945/

I know it's in Polish, but you can see some graph out there.

0 4221014 over 5 years ago in reply to JacekThomann

Thanks! What I like the most about your reviews is that they are written with a more mature version of the firmwares. I always wonder if this would change some conclusions made by early reviews that were written with an initial firmware version -- sometimes even before the product has reached the market! More than that: can we see reviews comparing the initial firmware release with the current one (months after the product reaches the market)?

0 JacekThomann over 5 years ago in reply to 4221014

Unfortunately not, because I only get a watch for review for 3-4 weeks and has to send it back. I'm not a beta tester so if I will not buy the watch it's rather impossible.
Glad you like the review.

I will copy the review of 45 when it's done.

0 4221014 over 5 years ago in reply to JacekThomann

I see.

I'm looking forward to see your review of the Forerunner 45 :)

0 JacekThomann over 5 years ago in reply to 4221014

Here you go: www.goultra.pl/recenzja-garmin-45/

0 4221014 over 5 years ago in reply to JacekThomann

Thanks! I'm still reading it, but it seems there's a small error on the text just above the heart rate graphs. It's written Garmin 945, instead of Garmin 45. In the graphs, however, we can read Garmin 45, which is right :)