Smart watches and sleep apnea ?

[babydinosnoreless]

Does anyone use these smart watches for the blood oxygen and ecg and are they worth the cost ?

[lazarus]

For the record, I don't have any extreme views at all on "health toys" :

viewtopic.php?f=1&t=187391&p=1448025#p1447874

But if a company tells you outright in its disclaimers that its products aren't good enough to give actual medical-grade info, I say believe it.

And here is a somewhat scholarly overview from 2023 (good specifics are in the studies that the overview article lists in its source sheet at the end):

"Trustworthiness of smartwatches is a subject of concern due to the opaqueness surrounding the algorithms used for detecting and analyzing users' health information. These algorithms are kept from the general public, which introduces a level of uncertainty regarding their accuracy and reliability. Furthermore, research studies have pointed out that different brands of smartwatches yield varying results when diagnosing clinical symptoms, sometimes even diverging from those provided by traditional medical devices. Recent studies have examined the accuracy and precision of various smartwatch models compared to medical-grade pulse oximeters. . . .These findings suggest that while some smartwatches showcase favorable alignment with medical-grade pulse oximeters regarding accuracy assessments, occasional outliers as well as discrepancies remain present due to variations among different models and contexts considered during evaluations."-- (2023) "Smartwatches in healthcare medicine: assistance and monitoring; a scoping review."
Mohsen Masoumian Hosseini, et al. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10625201/

But, in general, I think toys are great. I have a few myself. Although I do know the difference between playing the game Operation and actually performing one.

[Janknitz]

I have an Apple Watch with a blood oxygen monitor, and I don't think I can count on it for accuracy. Trending, perhaps, but I question even that. It did seem to tell a story when I experienced some altitude sickness while visiting Sant Fe, NM, but I'm not positive the readings were particularly accurate thought I suspect my blood oxygen was low, as it indicated.

First, paying attention to the way it measures blood oxygen, you can either initiate the measurement, or it will take the measurement randomly, particularly during the night. Secondly, the range of normal for blood oxygen is very narrow 92% - 100%. Even if it is a few percentage points up or down, that's actually a lot on the narrow range of "normal".

If I initiate the blood oxygen monitor, the reading fails more than 50% of the time. I'm white skinned (because it's a light sensor, it doesn't work well over darker skin or tattoos), know how to hold still, and I can follow basic directions about how to position the watch and make sure the band is neither too loose nor too tight. And it STILL fails more than 50% of the time.

It takes 15 seconds of optimal conditions to get a single reading. I assume that it is taking measurements and averaging them to get the reading. Meanwhile a pulse oximeter can read second by second without difficulty on your finger.

I particularly don't trust the night time readings. They seem random (not at predictable intervals) and when mine was reading particularly low I used a recording pulse oximeter that told a different story. None of my readings with the recording pulse oximeter was low, I was using my CPAP which I generally expect to keep a good blood oxygen level at night (and it is). How could the measurements be taken so easily without intention, when they rarely work WITH intention???

Apple makes NO claims of accuracy and warns Apple Watch wearers NOT to rely on the readings. And I think that is correct. So if you want to buy an Apple Watch for blood oxygen readings alone, it's not worth the money, IMHO. The Apple Watch has many more attributes that make it worth the investment, but Blood Oxygen is the least of them.

I have no experience with FitBit or other brands, so I will not speculate on them.

[chunkyfrog]

The primary benefit of any of these consumer devices is to
focus the user's interest on healthy activity.
If you can maintain motivation without a gimmick, you win.
If not, THEY win.

[galeforcewinds]

In my opinion, if you want to measure blood oxygen reasonably accurately overnight, you'd best buy an oximeter for that purpose. I have an oximeter (a LOOKEE) and a Fitbit. The Fitbit reads consistently a little low. And although it claims to measure oxygen variation, the resulting chart doesn't always match with the readings from the oximeter very well.

[babydinosnoreless]

Thanks for the thoughts. I was asking because of a conversation I had with a co-worker about the patent dispute with apple. I am not planning to go get one. Not at their current price anyway.

[lazarus]

I consider Apple products some of the best in the market segment, and I consider the company one of the best for a good consumer experience. Yes, they are expensive, so you pay through the nose for it. And no, the health aspects/apps aren't as good as that of cheaper overnight recording oximeters, in my opinion. It is more the other features of the watch that are high-quality and dependable and convenient.

[Tec5]

I was asking because of a conversation I had with a co-worker about the patent dispute with apple.

Masimo is a principle manufacturer of medical components and systems, and in particular oximetry. The lawsuit, going back to 2020, is not just a simple patent dispute, rather Apple is accused of theft of intellectual property and reverse engineering components used for Apple watches. For that reason, Apple voluntarily decided to pull Series 9 watches from the market, and so their newest watch was unavailable for sale for this Christmas.

If this accusation is true (trial court was hung a couple of years ago), it would suggest that Apple's oximetry function is as capable as Masimo's.

BTW, the FDA criteria for approval of a "medical device labeled" oximeter is that the device manufacturer has to show that the device's output is within 2% units of a lab-acquired arterial blood gas determination. So a reference value (blood gas determination), of 92 needs to be matched to an oximeter's output value of 94 to 90 in order to satisfy FDA's requirements.

[dataq1]

I have a bit of a different take on the smart watch disclaimers.
The smart watch manufacturers are focused on the consumer market, that's where they will make money.
FDA approval for a medical device is loooong and very expensive, so why would the watch manufacturers even waste the time and effort to apply for FDA approval even if their oximeter systems were of equivalent accuracy? Apple is not likely to sell another thousand watches based on a FDA approval, so why bother.

As to the disclaimer itself, that's just basic legal protection to avoid lawsuits from a user who "thought" that it could be used in a strict medical setting. They "thought"
that because Apple didn't say otherwise. (reminds me of the "don't dry the cat in the microwave" disclaimer - not that it doesn't work, but there could be some unintended consequences).

[lazarus]

"The new Apple Watch says my lungs may be sick. Or perfect. It can’t decide. Both the Apple Watch Series 6 and Fitbit Sense have new blood-oxygen apps. They’re mostly useless."

Geoffrey A. Fowler. September 23, 2020.

"Over several days of comparing my second Apple Watch’s measurements to my FDA-approved finger oximeter, Apple’s readings most often differ by two or three percentage points — though they’ve also sometimes exactly matched, and sometimes have been as much as seven percentage points lower. . . . There could be consequences if consumers actually believe the hype about these devices. . . . 'It is a dangerous trend for technology companies to release medical devices that don’t meet FDA standards and claim that they are not medical devices,' said Brian Clark, a pulmonologist and professor at the Yale University School of Medicine. The most common negative consequence is likely to be people calling their doctors too often because of false low readings. 'But the more concerning and potentially dangerous scenario is when the devices provide false reassurance and people don’t seek health care when they really need it,' Clark said. . . . Researchers told me they were excited by the addition of blood-oxygen data — but there’s not enough information about its validity. 'We have toys, and we have things that are used for clinical purposes. And it really needs to be a clear distinction,' said Duke University’s Jessilyn Dunn, an assistant professor of biomedical engineering."--https://www.washingtonpost.com/technolo ... -oximeter/

[dataq1]

"The new Apple Watch says my lungs may be sick. Or perfect. It can’t decide. Both the Apple Watch Series 6 and Fitbit Sense have new blood-oxygen apps. They’re mostly useless."

To be fair, you should point out that "useless" is the conclusion of the Washington Post writer (not the rep from Duke)

On the other hand you have this from a more recent medical review:

Our review suggests that the Apple Watch Series 6 does not show a strong systematic bias compared to conventional, medical-grade pulse oximeters. However, outliers appear to occur fairly often even though we could not determine a definitive frequency and should not cause concern in otherwise healthy individuals. - Accuracy of the Apple Watch Oxygen Saturation Measurement in Adults: A Systematic Review, 2023 Feb; 15(2): e35355

https://www.ncbi.nlm.nih.gov/pmc/articl ... s%200.993.


Another interesting excerpt from the Post newspaper is this:

Heneghan still wouldn’t disclose the Fitbit’s exact error rate. But he said it beats the range set by an international standards organization. That’s not much to brag about: It would allow someone with a true SpO2 reading of 95 percent to be told they’re at 91 percent.

If I read that correctly, a (unnamed) international standards organization allows an error rate of plus/minus 4 units.

[Max46]

Talk about useless, here's a screen shoot of Fitbit's output for overnight oxygen. No actual data, no idea what the distinction is between high and low variation, "high variation @ sometime (have to guess) 5am and 6 am.

[lazarus]

“ 'If we were to make a claim, like we could detect sleep apnea, we would definitely go through the regulatory process and be very clear on our messaging and very clear on the limitations,' said [Conor] Heneghan [Fitbit’s director of research]."--Geoffrey A. Fowler/The Washington Post; from 2020 article linked above.

In other words, 'we will gladly sell you a car, but by making no claims that it is actually safe or drivable, we will then bypass all car regulations and expectations of transparency by any drivers who mistakenly thought that the toy we sold them actually works.'

What a "clever" marketing tactic!

[dataq1]

“ 'If we were to make a claim, like we could detect sleep apnea, we would definitely go through the regulatory process and be very clear on our messaging and very clear on the limitations,' said [Conor] Heneghan [Fitbit’s director of research]."--Geoffrey A. Fowler/The Washington Post; from 2020 article linked above.

In other words, 'we will gladly sell you a car, but by making no claims that it is actually safe or drivable, we will then bypass all car regulations and expectations of transparency by any drivers who mistakenly thought that the toy we sold them actually works.'

What a "clever" marketing tactic!

Interesting analogy that perhaps highlights a significant part of the problem'

In fact thousands of cars are sold every day with a speedometer that reads up to 140 mph. But the seller makes no claim that the vehicle is safe or drivable at such speeds. That it might or could be is in the mind of the buyer.

It may well be in the mind of the buyer that this or that watch can detect sleep apnea, and you and I know that clearly is foolish. But the issue is that it is a concept that could well be in the mind of the buyer/owner. Are manufacturers being "clever" if they fail to explicitly state that their device is incapable of detecting sleep apnea? (reminds me of the "don't dry the cat in the microwave" statements)

It's the purchaser that is ASSUMING facts/capabilities not in evidence.

[lazarus]

Today we are thrilled to announce that we have added an exciting new Cat-Dryer feature to our latest line of microwaves!*

*Please note our disclaimer hidden deep in the manual which states that our product should never be used for actually drying cats.