Author Topic: Pulse oximeter in your wearable  (Read 795 times)

Pulse oximeter in your wearable
« on: January 22, 2021, 05:56:10 am »
My Garmin bought last year has a built in pulse oximeter.  From what I have read and experienced using it the readings were worryingly low (often well below 95) and they fluctuated massively between high eighties and high nineties   Yes, that is quite a range and with the now widespread advice re covid I see that below 95 is of concern.

So, I bought a "medically approved" finger jobbie.  Thankfully my readings range between 98 and 99.

I also discovered that using the pulse oximeter full time was sucking half of my Garmin's battery life.

My opinion of the Garmin pulse oximeter is that it provides erratic and/or unreliable reading and causes excessive power consumption and as such is a less than useful feature built into the watch.  I note that the Garmin app seems to see 90 and above as OK which is perhaps their "adjusting" to the relative inaccuracy (my opinion) of the device but given current medical opinion this is not helpful in my opinion.

I'd be very interested in the experiences of other wearable users which have built in pulse oximeters.

PaulF

  • "World's Scariest Barman"
  • It's only impossible if you stop to think about it
Re: Pulse oximeter in your wearable
« Reply #1 on: January 22, 2021, 06:17:43 am »
Usually when a wearable device gives erroneous readings it suggests that’s it’s not being worn correctly.

As for the battery life I think I read that Garmin actually warn you that it can use the battery if used continuously so no surprise there. I think that blood oxygen is one of those statistics that has no real value in being continuously monitored unless you have a medical condition that requires it. If that were the case then I think you’d be better off using an approved device rather than a sports watch.

ElyDave

  • Royal and Ancient Polar Bear Society member 263583
Re: Pulse oximeter in your wearable
« Reply #2 on: January 22, 2021, 06:58:56 am »
I don't use the Garmin one for all of those reasons you say. It routinely gives me <95 vs 99+ for the finger job, which was bought a few years ago during a bout of chest infection in our son.
“Procrastination is the thief of time, collar him.” –Charles Dickens

Re: Pulse oximeter in your wearable
« Reply #3 on: January 22, 2021, 07:09:42 am »
My research also shows that the wrist is a less reliable place to take the reading than the fingertip.  Also, it is necessary to keep still whilst taking the wrist reading.  Further, the band does not have an infinite adjustment, rather a stepped one dictated by the holes in the strap.  Therefore it is not possible for somebody to properly set the sensor for measurement without being painstakingly fastidious.  These factors for me having worked it out in hindsight make the device less than sensible.  And you are right, reading are best taken occasionally and deliberately.

Garmin's warning about battery life is very non-specific and not really well presented.  Something that can suck half of battery lifenis quite significant imo.

I have just taken my reading using the finger device:  SpO2 99, pulse 46.

Hot Flatus

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Re: Pulse oximeter in your wearable
« Reply #4 on: January 22, 2021, 07:12:05 am »
Yes, same experience as you.

Re: Pulse oximeter in your wearable
« Reply #5 on: January 22, 2021, 07:54:46 am »
Impressively low heart rate there PB!

Last time I measured my blood oxygen sat was when I visited the hospital with youngest with an asthma attack. I tried the monitor whilst she was between measurements. I had considered swapping out the 935 to get the pulse ox, but reports of inaccuracy have put me off, plus it seems the 945/Fenix 6 actually have lower go’s accuracy too - all Internet anecdote of course.

Mike

Re: Pulse oximeter in your wearable
« Reply #6 on: January 22, 2021, 08:25:52 am »
I think watch pulse oximetry is about 10 years behind simple pulse measurement.  Reflectance pulse oximetry is very difficult which is why it is not commonly practised. https://www.sciencedirect.com/science/article/pii/S2405959516301205 is a reasonable summary.

in hospitals and ones for the fingertip work on transmission rather than reflectance which apparently is easier.  You also need an extra LED for the extra wavelength which eats up the battery.

Re: Pulse oximeter in your wearable
« Reply #7 on: January 22, 2021, 08:36:44 am »
My resting hr has remained fairly static in the 22 months that I have been recording it.  What has changed is how long that I can maintain high hr's without feeling any adverse affects.  I also seem to be able to go much higher than my age would suggest for threshold and max hr without any obvious side effects.  I recently started using a chest strap which seems more consistent but the range has not noticeably been affected.

Having finally worked out what features of the Fenix 6 work for me and what do not I am relatively content.  There are many things that I don't really like about it though and I am much wiser in respect of what I need from a wearable than I was before I bought this one.  This was an emergency purchase though as my 735XT developed a critical fault outside of warranty and I really felt that I needed uninterrupted data at that time: I was two months into C25K and keen to keep proper track of progress.

T42

  • *** fool in a hurry
Re: Pulse oximeter in your wearable
« Reply #8 on: January 22, 2021, 08:45:14 am »
Last time at doc's his finger jobbie gave me 98%, which matches the score on my wrist jobbie. OTOH my own finger jobbie usually gives me 92%. Moral: not all finger jobbies are created equal.
I've dusted all those old bottles and set them up straight.

Re: Pulse oximeter in your wearable
« Reply #9 on: January 22, 2021, 09:02:44 am »
My Garmin has been remarkably consistent (no idea on accuracy of course but I assume on the low side), at 95.  I don't find having to stay still to measure it for <1 minute a chore as I choose when to do it (often in Teams meetings!). Strap tension isn't IMO really an issue either as long as it's not slipping about.
We are making a New World (Paul Nash, 1918)

Re: Pulse oximeter in your wearable
« Reply #10 on: January 22, 2021, 09:04:56 am »
Watching this thread with interest as we’ve just bought a Beurer PO40 and I’m about to invest in a Garmin for Mrs DF. Sounds like I shouldn’t be too hung up on the presence of this feature in whatever Garmin we eventually go for.

A

Re: Pulse oximeter in your wearable
« Reply #11 on: January 22, 2021, 09:08:28 am »
Indeed, I never knew that mine would have one before I bought it, it ceratinly wasn't a "must have" and I'd not miss it at all.
We are making a New World (Paul Nash, 1918)

ElyDave

  • Royal and Ancient Polar Bear Society member 263583
Re: Pulse oximeter in your wearable
« Reply #12 on: January 22, 2021, 09:43:42 am »
Impressively low heart rate there PB!

Last time I measured my blood oxygen sat was when I visited the hospital with youngest with an asthma attack. I tried the monitor whilst she was between measurements. I had considered swapping out the 935 to get the pulse ox, but reports of inaccuracy have put me off, plus it seems the 945/Fenix 6 actually have lower go’s accuracy too - all Internet anecdote of course.

Mike

Having had, in the past various Garmins including 310XT, another XT, Fenix 2, now Fenix 6 "Pro" and a couple of bike-specific, I can't say I've noticed any lower accuracy in the Fenix 6 vs Fenix 2.  I swapped there because of the declining battery life on the 2, and the temperamental attitude to saving and uploading stuff.

I've yet to use the "jumpmaster" feature on either of them.
“Procrastination is the thief of time, collar him.” –Charles Dickens

Re: Pulse oximeter in your wearable
« Reply #13 on: January 22, 2021, 06:13:18 pm »
Impressively low heart rate there PB!

Last time I measured my blood oxygen sat was when I visited the hospital with youngest with an asthma attack. I tried the monitor whilst she was between measurements. I had considered swapping out the 935 to get the pulse ox, but reports of inaccuracy have put me off, plus it seems the 945/Fenix 6 actually have lower go’s accuracy too - all Internet anecdote of course.

Mike



Having had, in the past various Garmins including 310XT, another XT, Fenix 2, now Fenix 6 "Pro" and a couple of bike-specific, I can't say I've noticed any lower accuracy in the Fenix 6 vs Fenix 2.  I swapped there because of the declining battery life on the 2, and the temperamental attitude to saving and uploading stuff.

I've yet to use the "jumpmaster" feature on either of them.

I thought, at first, that jumpmaster must be a mountain bike thing😯