Everything is wrong with my 935

Phil is curmudgeonly sure and doesn't always take the time to explain things (and in this case I agree with for not doing so), but it's been said ad-nauseam and analyzed over and over here and in professional tests.

That's 'cos I'm old :-)

But there are many of us that have no problem with the wrist HR and get perfectly sensible readings (max HR, VO2max, etc etc). On the contrary, i always had serious problems with the chest strap. It wasn't until i moved to the optical that i finally got consistently stable numbers that i could rely on.

Just saying don't be so absolute with your statements.

There are a few, who don't experience problems with wrist HR (in comparison to the many, many more, who do have problems). This is across all devices and all manufacturers. Optical measuring of HR from a wrist worn device during 'active' activities is not a reliable method to accurately measure heart rate. Period. If it works for any individual, that's great.

And yes, there are some people who do have problems with chest straps for whatever reason, but those are definitely in the minority.

I suspect that happened because a max HR was detected in error. To avoid that happening in future, you might be best placed to turn off automatic detection of max HR.

Yeah look not meaning to start a HR war here about the two different methods. There are pros and cons to both. My comment was about statements of absolutes and certainty.

DC Rainmaker perhaps provides a good baseline, and a much better guide than the valencell tests in that 2017 article (e.g. every one of his reviews have multiple tests, using real life running conditions, and we can see the actual data not just the % relative to a strap which itself may not be accurate). One of his gold standards for many years has been the Scosche OHR, which does a great job at pretty much every type of run, almost always equivalent to any chest strap and often more stable (without the issues many people have with straps at the start).

Elevate certainly struggles when your HR changes rapidly, like with intervals. The numbers usually aren't garbage (any more than that you can get spikes and low readings from a chest strap on any given day). Just the equivalent of really low resolution from my own experience and seeing a lot of other people's. Garmin does need to do better at this.

People tend to come to the forums when they have problems with their HR readings. You can't gauge the majority experience from this. And the forum isn't flooded with such posts, for example.

The difference between strap and OHR, in terms of accuracy and reliability, has narrowed considerably over the past few years and are probably now within the variance of each other.

I agree with both Philip and Darren. Yes, the majority of the time the HR strap is superior to the oHRM. It definitely is in my case. But it's not a definitive across the board. My wife has tested a HR strap against her oHRM and the difference is between 2-3 bpm. The oHRM just works great for her and that's with running or fast tempo/movement cardio.

DC Rainmaker perhaps provides a good baseline, and a much better guide than the valencell tests in that 2017 article

Ray, while a trusted name for opinion, is a blogger 1st and foremost. His reviews are not lab tested and is using either: reviewer devices or market ready products. He has a proprietary program to test the devices on, but he is using (1) person (himself) for (1) exercise (himself) in a quasi-controlled environment. There are no control subjects, no variants, nothing. I don't think he's misleading or incorrect; but he also cannot do more than give his opinion--skilled and informed as it is. Lab tests done in a controlled environment are going to be far more informative. I like Ray, but I take everything with a grain of salt from him.

One of his gold standards for many years has been the Scosche OHR

This is a Valencell OHRM (and now replaced this year). Also if you read my first point--Wristbased OHRM are the point here for inaccuracies. The Rhythm + is a forearm/bicep OHRM.

almost always equivalent to any chest strap and often more stable (without the issues many people have with straps at the start)

Conjecture and opinion. I had and used one and found it either slow to report, the signal cut out all the time and found wearing it on my bicep while uncomfortable, being the most stable place to get a reading and not have the signal drop off. Almost and precise are night and day. Lab tests find OHRM 80-97% to a chest strap...which is 97-99% to EKG readings. That's a big window for fluctuation. I recently owned the aforementioned Tickr fit and found it 10-20 BPM below what the chest strap was giving me (TICKR connected to the watch, the strap to a phone app). This meant work done put me in a completely different HR zone (HIIT training routine with Z4/Z5 peaks all the time), affected all my Training effects, calories were incorrect etc. Even in cases of 3-5 bpm differences it meant a different outcome. Is this going to be the same outcome for everyone? No, but my point is person to person is not a good measurement or standard to base the point on in the first place.

As for at the start not being accurate, wet the electrodes either with water or electrode gel. That is human error not the strap.

Elevate certainly struggles when your HR changes rapidly, like with intervals.

Elevate is not alone here, ALL wristbased OHRM suffer here. Personal opinion: Z1/Z2 work with a Wristbased OHRM is closer in line to the reporting from a chest strap. Once you crest Z3, all bets are off, throw in weights (muscle flexion) and it's not coming close to being accurate.

The numbers usually aren't garbage (any more than that you can get spikes and low readings from a chest strap on any given day).

Again, I ask if you have done these measurements over a number of exercises? Because I have...for years, over a number of Garmin watches. I don't know what chest strap you have used where you get spikes/ low readings (other than a complete disconnect from the watch or a failing battery or it's just an old strap) but I personally haven't seen this and this is the first time i've ever read someone making that comment.

You can't gauge the majority experience from this

Absolutely, which is why I normally talk about it, but listen to the pro's and experts on the actually studies.

And the forum isn't flooded with such posts, for example.

Just by your user tag, you've been here since 2011, who are you trying to fool here? Type OHRM for example in search and see for yourself.

The difference between strap and OHR, in terms of accuracy and reliability, has narrowed considerably over the past few years and are probably now within the variance of each other.

This is your opinion, and a blanket opinion at that. In what way are they more accurate? Running? Cycling? Swimming? Skiing? How are they more reliable? Where are the reports showing this? The lab tests say otherwise. Even people like Ray when talking about Wrist Based OHRM say this more or less. Is there a chance they get better? Yes of course, I would love to see this myself, until then i'm going to continue to rely on my chest strap for giving me the closest readings you can get.

My chest hrm is OK with cycling. Running however was always a drama. My optic wrist hrm performs far better when I run.

What a comprehensive and well reasoned reply jstpassaro.
I bought the 935 on the promise of advancements over the 920xt and the new OHR/WHR feature.
I read Ray's (DCR) review and the 935 looked good.
I soon found out that the OHR data was inaccurate for running, walking and bike riding and ended up buying the tri and swim straps to get satisfactory HR readings.
I replaced the watch because even while hiking OHR readings surged and were often 20 to 30 bpm higher than measured (verified using the watch and feeling a pulse). I expected better performance for walking and thought there was a hardware problem.
The replacement watch was the same.
OHR readings while not moving were pretty good.
I see lots of statements like this in the forum:
"You cannot expect stable, accurate, or sensible readings from the wrist HR. You need a strap."


I wish that Garmin had made a similar statement in their 935 watch specification documents. ?

Thanks jstpassaro for your response, you clearly put a lot of thought into it. I don't disagree with a lot of what you say. Yeah i've run a lot of kms with HR (10s of thousands). Yep with a lot of devices (primarily Garmin), and both straps and optical (wrist and forearm). Yeah i know Scosche is Valencell. Yeah i know about statistics and studies and sample size and controls. Yeah i know you have to lick the strap or use gel before you run, which is always fun on a cold morning in the dark. Etc etc.

And yeah it sounds like you've had a really mixed experience with OHR. That sucks, because i think one thing we can both agree on is that a HRM built in to your watch is far nicer to have than to something you have to strap around your chest, **IF** accuracy can me maintained. Maybe you're right and i'm part of a rare and lucky group.

If there's one thing i've learnt in my time on these forums (since 2011! - thanks for reminding me), there are two things that are argued to death with almost religious zeal: GPS accuracy and HRM accuracy (more recently). And which often degenerate into people talking past each other, misunderstandings or selective reading, subtle and not so subtle personal attacks, etc. So i'll leave my comments at the above since i'll just be rehashing what i've already said otherwise (and especially not respond to things like "who are you trying to fool", which was unnecessary).

To end, something that might be helpful: my 735XT's band is long enough that i can wear it in the middle of my lower forearm on the inside (fleshy part). This might help some who are struggling to get a good reading from the more standard wrist locations. Though I also have "runner arms", so not everyone will be able to do this.

Well said.

lick the strap or use gel before you run

I soak mine in warm water before every run. No licking. No gel. And more comfortable to put on.