Wrist HR worse accuracy?

[Egika]

@efejota said in Wrist HR worse accuracy?:

Maybe this is a stupid question, but, why cold may affect readings, considering that HR is measured using light?

The measurement is not affected - your body is
In cold temperature the outer blood vessels contract when it gets cold so there is less blood flow to be seen by the optical sensors.

[thanasis]

@regger I tried the following (which kind of validates @Dimitrios-Kanellopoulos findings)

while running against the wind (with quite a cold stream), I immediately noticed a significant increase in the BPMs which did not reflect the actual status

[Efejota]

@thanasis I guess is similar to my case. I will check it. And it seems to be consistent with the “cold” explanation.

Thanks for your explanation, @Egika

J

[Dimitrios Kanellopoulos]

My advice is:

Warm up indoors your hands and wear gloves. Some flexing helps. Nothing big.

I get bad results if I exit home and be like: ok let’s get started not warmed up , shaking from cold.

Also the more thin you are the worse I think it is.

[Efejota]

@dimitrios-kanellopoulos I am like the second choice. About the thinner, the better, I can then get rid of the scale and trust my watch…

[thanasis]

@dimitrios-kanellopoulos the advice is simple: eat more

[Dimitrios Kanellopoulos]

@thanasis trying

[suzzlo]

Wrist HR has improved a lot in last year’s (no matter which brand are you using) but chest band is always similar or better.
My recommendation is to use the band when good accuracy is required

BR

[ChrisA]

@suzzlo besides accuracy I also prefer a HR-belt in winter, because you can wear your Suunto over your clothing then, making it much easier to glance at it than working through layers of gloves, Shirts and Jackets

[Efejota]

@chrisa You are right, I didn’t think of that.

[suzzlo]

@chrisa totally agree. Wearing globes is sometimes a must! or think when you are swimming with a long suitwear…

[Efejota]

Dear all. After struggling with very bad readings using OHR, I decided to make a test. I recorded a run today and used the belt and the Suunto App in the phone to compare. This is the result (OHR is blue)

Things I noticed.
(1) There are a lot of 0 reading. You can see them in the blue lines. In comparison, the belt almost had no failure.
(2) There is a HUGE difference of accuracy when I decided to put the watch AND MY HAND into my sleeve. It seems that the problem is having cold hands, and not cold arm.
Even then, there are some peaks. You can see when I decided to put it into my shirt: the graphic is very similar since after the first part. I put it out again and notice almost no difference until the last part, where you can see a peak. The watch was outside the shirt since some time before and the performance seems not to be affected.

Seeing this I must say that weather makes a big difference, even if it is not very cold (around 11º today), at least in my case. I have no explanation to the big difference at the end. Environment and watch position did not change.

Finally. At the end, I tried with both the basic OHR and the app, and noticed that it takes about 1 min for the watch to stibilize. Since then readings are more or less consistent, although big arm movement (watch position unaffected) raised the numbers, that were stable according to the belt.

I hope that this info is useful. I will keep trying to reach a definite conclusion with more runs and different weather.

[aroo7]

@efejota stop kidding yourself wrist-based heart rate measurement during an activity doesn’t make much sense. The wrist is a poor place to measure your heart rate. It flexes, gets cold quickly and, moreover, has few blood vessels. Wirts OHR in S9P is really good and does its job but outside of training when you rest and recover.

[Dimitrios Kanellopoulos]

@efejota said in Wrist HR worse accuracy?:

There are a lot of 0 reading. You can see them in the blue lines. In comparison, the belt almost had no failure

Those are not 0\s your app is converting them

[Efejota]

@dimitrios-kanellopoulos I simply downloaded the GPX from QS, in fact, and extracted as CSV to be used in Excel (after struggling in finding a free alternative to compare two .fit or .GPX files, any advice?). Are they not zero readings?

J

[Efejota]

@aroo7 I do not fully agree. My experience when I started using S9P in August was impressive. It was really accurate. Of course I do not pretend it to be as precise as a belt or an ECR, but those differences are substantial. If I have to believe those readings, I should visit the doctor. That is why I am trying to understand why, because it is obviously more comfortable to wear the watch, without the belt.

I have an additional question. Is it possible that readings can be affected by movement? Even with the watch properly attached to my wrist, in slow exercises (hiking, for instance), numbers are very precise (I assume that readings are poor if the watch moves constantly around my wrist, I refer to watch remaining at the same place and affected only by arm movement).

J

[isazi]

@efejota said in Wrist HR worse accuracy?:

I have an additional question. Is it possible that readings can be affected by movement? Even with the watch properly attached to my wrist, in slow exercises (hiking, for instance), numbers are very precise (I assume that readings are poor if the watch moves constantly around my wrist, I refer to watch remaining at the same place and affected only by arm movement).

Measurements are affected by movement, and by what you do with your hands (together with temperature). Movement may add noise to the readings, what you do with your hands and temperature may affect blood flow.

[Egika]

@isazi and using poles almost ruins everything…

[sartoric]

yep, as you’re flexing muscles repeatedly

e.g. weight lifting is one of the most challenging sport to monitor with WHR