Wrist HR worse accuracy?

[surfboomerang]

@efejota I have seen some inaccurate readings the last couple of weeks. My readings were more consistant in the summer. I blamed the cold weather for the worse readings. Especially in the beginning of an excercise.

The one thing I couldn’t explain was a sudden longer drop of 20-30 bpm for a longer period (± 1 min) after a long period (30 min+) of stable measurements. I’ve seen this behavior a couple of times during my runs in the previous weeks.

[isazi]

@efejota I have not noticed anything strange, and I always run with two watches (one of them paired to a chest strap).

[surfboomerang]

Coincidence or not but a soft reset gave me a very consistent reading on this afternoon run.

@Efejota It’s worth a try…

[Brad_Olwin]

@efejota Mine is worse because of winter. I use a belt when the temperatures drop.

[Dimitrios Kanellopoulos]

Worse here due to cold weather. Use gloves and also make sure arms are warm

[Efejota]

@dimitrios-kanellopoulos and @Brad_Olwin, thanks for your info. Might be it. I will try a different approach (like having the watch inside a glove even if I cannot read it to see if it makes a difference.

@surfboomerang I will try the soft reset and check it afterwards.

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

J

[regger]

@efejota
Yes, it got worse in the last time…Very bad accuracy…I tried to clean the watch, to use another position on my hand…

[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.