Suunto 9 Peak HR is SUPER Inaccurate

Grayson Bangay

Good morning folks,

First time posting, and unfortunately out of frustration. Switched from garmin to suunto about 3 months ago. Bought the Suunto 9 Peak for Fenix after lots of deliberation, and wasn’t really disappointed until i started ‘tracking’ workouts that weren’t running or seemingly steady in pace.

The HR, of course is where this was most noted. Weightlifting, circuit training, sprints, etc, seemed to pull the oddest and most erratic of HR’s. I’m talking, 10 minutes into a core circuit and it’s reading 60 BPM. Weight lifting at 80 BPM’s solid for an hour. (Actual HR was mid 120’s) This happens constantly! I have trouble shot, everything I can. Position of the watch, hard restarts, firmware updates, you name it, I’ve done it.

An odd thing that does happen, the minute I take the watch off and place it on a table, it reads the HR it should. For example, It’s reading 68 BPM on my wrist - I then take it off, and it climbs over the next minute to 120. What my HR is actually at, since I have a garmin on my other wrist (And it’s reading correctly)

Haven’t seen anything else online, besides my small inaccuracies people have experienced. Yes, I could just buy a HR chest strap. But, that’s the frustration I shouldn’t have to, if another watch could do this without fail.

I appreciate anything I may not have thought of, or out of the box ideas!

Thank you for your time Sunnto community, Grayson

DMytro

@grayson-bangay I think what the watch reads while lying on a table is a coincidence - it can’t measure HR without having a direct contact with your arm (maybe via software update someday XD).
As for the accuracy while weight lifting or doing a circuit training - I thought it was a common shortcoming of wrist based OHR sensors, you could maybe try to place your watch higher on the arm or on the inside of your wrist, but other than that I fear it’s not much you can do.

sartoric

as a general reference there this old but gold post:
https://www.suunto.com/Content-pages/what-should-you-know-about-wrist-heart-rate2/

That said, I would expect some inconsistencies for weight lifting but not for running or similar.
Check that you haven’t tighten it too much.

I would suggest to search the forum too for the HR topic. There are plenty of discussions about it.

Grayson Bangay

Perfect. Thank you guys.

Again coming from Garmin, the accuracy and speed of change in HR never seemed to have a problem, or I possibly wasn’t noticing that I care more about these things Ha

Haha @DMytro Yes, correct! It’s always funny though, that instead of erroring or having dashes come up, it matches without fail, every time, what my HR is currently sitting at. Never above or below! Confirmed again while wearing another watch. As if there’s a 10 second delay…

cs2nd

@dmytro I believe (and in my experience too) is that there is a delay. I believe the sensor is reading on the second, but the display refresh is delayed. I’d love to be proven wrong though.

DMytro

@cs2nd that too is a peculiarity of all optical HT sensors, that’s why HR strap is usually better for interval training.

cs2nd

@dmytro you are 100% right. I personally religiously use my Polar H10. The issue still remains though, there seems to be a lag/delay with what the SP9 displays. Otherwise, yes, I trust my Polar H10 readings.

DMytro

@cs2nd how bit of a delay are you experiencing? And how do you know that it’s a lag in the first place?
For example, if I climb a hill, my HR doesn’t elevate for the first few seconds either, but I am quite confident that it’s due to physiological reasons and not just a signal delay.

Brad_Olwin

@grayson-bangay I don’t care which one you have, Garmin, Suunto, Polar, Coros, TomTom, Apple, etc. The optical HR is just not that good. If you want accuracy use a belt.

https://pubmed.ncbi.nlm.nih.gov/28538708/

Simon

Optical heart rate sensors always have a lag of about 4-5 sec. Not sure, but I believe this is currently a general technical limit for all manufacturers.

As for accuracy: You can place the watch much higher up, where your arm is thicker. Or you can use an OHR arm sensor like the Wahoo Tickr Fit. It’s almost/comparable accurate to a chest band sensor, but less annoying. But it also has the 4-5 sec lag. It’s what I’m using and I’m really happy with it.

Cheers

jR0n6

@brad_olwin the link is 2017 which in tech world is like 10 years

If u looking for HR accuracy on wrist Apple Watch 6+ is very close to a chest strap… in my testing overall for a 2 Hour activity my difference to a Polar H9 was 2-3 beats (vs measures min / max)… the only issue is a lag up to 2 seconds…

This depends of course on your fit, skin etc…in case u require a scientific test u can refer to:
https://youtu.be/0Ub7qmZz9ec

P.S. Peak 9 is btw not bad at all for HR (for activities where the watch is not moving a lot…)

P.S.2.0 the best alternative if u don’t want to wear a chest strap… Polar Verity Sense, Polar OH1, or the mentioned Wahoo in that order…

Brad_Olwin

@jr0n6 I’ve tested all of the Suunto OHR models as well as Apple Watch 5 and 6. They are about equal for what I do. The Suunto 7 and Apple watches are a tie for me. And IMHO the best belt is the Suunto Smartsensor as missed HR and HR during swimming is synced bac to the watch. The belt can be worn 2-3h without the watch and sync back HR for exercises where one does not want to wear the watch.

jR0n6

@brad_olwin swimming is the only thing I did not try yet … for me the sensor of the Apple Watch is better but that 1,5 day battery life a no go… and was looking a long time for a watch that I like and the HR sensor is acceptable. S9P at least for me delivers this…

Simon

@jr0n6 Tried the Polar Verity Sense. It’s awesome Indeed better accuracy and more reliable than the Wahoo. Although the Wahoo is not bad by any means! And it has a longer lasting battery (20 h vs 30 h). Still, for the improved accuracy, I’ve switched to the Polar Verity Sense. Thanks for the hint!

Today first run with my new S9P (all black) via OHR.
I had the idea to test it with my old S9B with my smart sensor.
Holy shit is S9P accurate. I had nearly always nearly same values.
The average HR was exactly the same.
No drops or unplausible high values on S9P…
Amazing! Great job Suunto!!!

It was a steady run. Of course I would expect some difference in generell with every OHR device in compare to HR belt with fast sprints, unsteady sports…

I liked also the avg km pace of S9P.
Didn’t have so much jumps in the beginning of each km.

S9P all the way…

Dimitrios Kanellopoulos

@mountainchris keep in mind that during cold days of winter ohr has flaws due to its nature.

Summer is super accurate

@dimitrios-kanellopoulos it was 5 degrees. super good! in cold winter I will still use smart sensor. One indicator for me to use OHR is never have cold hands…

surfboomerang

As @Dimitrios-Kanellopoulos says…
Below a certain temperature OHR can become very unreliable but in warmer weather it works perfectly. Just use a strap in the winter for best results.

Warm weather

Cold weather