94-97 on Fenix 5x+ at Sea Level

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https://www.strava.com/...tes/zachary_mckinney

Strange. Do I need to worry about this?

The challenge with PulseOx is that it's constantly reading, even when you're moving. So those numbers tend to hose it up.

In reality, in a medical setting where pulse oximetery is used, the subject is still/at rest. Interestingly, if you read how the FDA certifies pulse oximeters, the variance allowed is still quite high, and the subject is seated at a desk with their arm on a table.

There's aspects in sleep where it's more interesting (because of lack of movement), but accuracy seems to depend on exact fit, and in some cases just dumb luck.

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My tiny little slice of the internets: dcrainmaker.com

Thank you. I feel fine but it’s sort of worrisome

What are your sleep numbers vs. your awake numbers?

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Trent Nix
Owned and operated Tri Shop
F.I.S.T. Advanced Certified Fitter | Retul Master Certified Fitter (back when those were things)

Don’t trust sleep necessarily. I was getting not horrible but lower numbers when I slept. But I sleep on that arm a lot and if you do it can cause it to read weird.

These are not medical devices. If you have any concerns about the outputs then go seek medical opinion or testing with certified devices.

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Trust me I’m a doctor!
Well, I have a PhD :-)

80 to 89 sleeping

80-89 sounds like coronavirus or high altitude acclimation

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https://www.strava.com/...tes/zachary_mckinney

I am a doctor and those values are not normal.
Now, the issue is whether it is the garmin which is the issue or you.
I would personally not rely on the garmin, you could easily compare with a pulse oximeter from your GP etc when you are reading low, but those overnight values are concerning and could point to obstructive sleep apnoea, which can occur in slim people as well as over weight people.
Have a quick google for the STOPBANG criteria as a simple screening tool and it will give you an idea as to whether you may suffer from OSA.

Thanks. As it happens I had to see my GP anyway today and I had it read there and it was 96. So I guess I need to 5 pts to the Garmin reading

Get a sleep study done.

Sure, your 945 isn't a 'medical device' (whatever that actually means - nothing becomes magical because a physician uses it) but they are gathering useful data nonetheless. And your 945 is telling you that you may not have sufficient blood oxygen saturation while you sleep. A closer look with better, specialized equipment is warranted.

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Trent Nix
Owned and operated Tri Shop
F.I.S.T. Advanced Certified Fitter | Retul Master Certified Fitter (back when those were things)

I just checked mine and I'm never above about 75, should I go to the doc?

I would almost certainly think your reading is faulty. Co sister readings under 75 would result in significant health issues that I would think would have already gotten you to the doctor.

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Trent Nix
Owned and operated Tri Shop
F.I.S.T. Advanced Certified Fitter | Retul Master Certified Fitter (back when those were things)

Wait...I thought the magic of medical devices is a demonstrated ability to produce a high level of accuracy and repeatability in whatever that medical device measures?

Like...my polar H10 HRM is pretty awesome at measuring HRV but it does not replace an EKG...that kind of magic...am I wrong?

I’m just pointing out that simply because the data was gathered on a consumer device doesn’t necessarily mean the data is to be ignored or assumed to be incorrect. Physicians and their equipment are granted more deference than is deserved.

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Trent Nix
Owned and operated Tri Shop
F.I.S.T. Advanced Certified Fitter | Retul Master Certified Fitter (back when those were things)

I both agree and disagree with you Trent. When a device like this Garmin 945 shows readings which, for someone who as part of their day to day job, takes both healthy and unhealthy people, induces unconsciousness, paralyses them, ventilates them, monitors them extensively (including requiring a detailed knowledge of how each monitor is deriving its values, which wavelength of light it is using, how it is calibrated and what the potential inaccuracies and problems are), including both invasive and non invasive measures of oxygenation and other aspects of respirations, and then that Garmin 945 shows sustained readings which would mean that the person should be in an Intensive Care Unit or maybe at the Summit of Mount Everest, then the device is likely to be wrong and not trusted.

In terms of what I agree with you about Trent, firstly, you are an amazing bike fitter (thanks for all that you do in that regard on here!), secondly, the medical profession does itself no favours at times when it comes to junk therapies, both under and over servicing when it comes to many aspects of care and I could probably go on and on and on.

In this instance though, the Garmin is clearly producing junk data. If there is something else going on to suggest major sleep issues then a sleep study may well be warranted. Obstructive sleep apnoea is seriously underdiagnosed even in fit normal BMI patients. It was a good recommendation as something that should be considered should the OP have other issues that may point to something going on.

Thanks for the nice words. Definitely hope you didn’t take offense at my words about “medical” devices. It really wasn’t a dig at medicine or physicians, just think we would all benefit from some healthy skepticism of the experts. And no doubt, your skepticism of the Garmin’s readings is warranted. I think we agree that any numbers that low would have other, actionable symptoms.

I just want to point out the actual readings aren’t really what spurred my recommendation to consider a sleep study - the difference between the waking numbers and sleeping numbers are what made me think an investigation is warranted. Maybe it’s nothing, but as you pointed out, sleep apnea is underdiagnosed.

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Trent Nix
Owned and operated Tri Shop
F.I.S.T. Advanced Certified Fitter | Retul Master Certified Fitter (back when those were things)