This is fascinating: smart watches can predict if you have COVID a week before you're symptomatic!

[thewayne]

It has to be a smart watch of fitness tracer that has a pulse monitor that also tracks heart rate variability (HRV), such as the Apple Watch 4-6. Some Fitbits and Garmins do this.

Here's the deal. You like to think your heart beats very regularly, the old phrase "his heart beat like a Swiss watch." It doesn't. The pause between each heart beat is slightly variable, hense HRV. HRV is measured in milliseconds and it varies throughout your day. At night it falls into a circadian pattern.

Now for the weird stuff. If you catch COVID, your HRV becomes LESS VARIABLE. Up to something like eight days before you become symptomatic, this is detectable!

They ran a small research program at Mount Sinai Hospital and several other hospitals, the Mount Sinai's program enrolled some 260 people who worked there who had an iPhone 6 or better, and an Apple Watch 4 or better. They loaded a program made in-house called Warrior, the people wore their watches for at least 8 hours a day, and tried to take daily surveys for how they felt. If they started feeling sick, they got a nasal swab PCR test, and if that was positive, they pulled the heart rate data for them and analyzed it. And started finding the data that I mentioned in the previous paragraph!

Now, the Apple Watch, and I assume the others, measure your pulse through shining an LED through your skin and it bounces through and is picked up by a photo diode that measures the result. That's how the pulse oxymeters that they slip on your finger in the doctor's office work. My watch will alert me if my pulse gets too high and stays there for an extended period. As far as I know, Apple isn't doing anything to notify you if your HRV becomes less variable, but the potential is there. They could be waiting for the papers to be peer reviewed or for the FDA to give approval or something. It's just like the fact that my Apple Watch 5 can do a three-lead ECG, it can't detect if I'm having a heart attack.

I don't know about how smart watch tracking works on non-Apple devices since I don't know them, but I can look at my HRV and see how it changes over a week or month. If you look at a year's worth of data, the averages smooth out too far to see any appreciable deviation.

Still, pretty nifty and another way to detect COVID!

There's a link in the CBS article to the Mount Sinai Warrior Watch study. It's not difficult to follow if you skip the more dense paragraphs.

https://www.cbsnews.com/news/covid-symptoms-smart-watch/

Comments

[graydon]

This is in one way really, really cool, and in another way really, really horrifying, because it implies that COVID-19 ALWAYS affects your heart.

[thewayne]

Actually, I think it's affecting the brain, not the heart.  There was another article that I came across a week or two ago about a study of brains of dead COVID patients.  I didn't read it, just saw links.  The doctors were expecting to see signs of oxygen deprivation because of COVID being a pneumonia-like presentation, and that's not what they found.  People are reporting dementia-like symptoms in some people who have recovered from the virus.  I was talking to my boss, the library director, yesterday, and she reported exactly this.  She has a younger sister (boss didn't mention her age) who recovered from COVID, was talking on the phone with her recently and sister looped back and repeated the exact same thing three times in the conversation, she'd never done this before in conversations.  When asked about this later, sister vehemently denied doing this.

[graydon]

Oh, it's pretty clear that any organ system can be affected. Brains definitely not excepted; the stroke anecdata about brains is horrifying. Up until at least recentish there was some hope it wasn't general with respect to cardiac function, but if they've got a diagnostic heart rate effect that would rule that out; it's certainly general with respect to cardiac function.

Which implies it might be general with respect to everything else, which in turn implies that it's not "what gets infected?" but "every organ system must roll a saving throw" which is ... less than good.

[thewayne]

Yeah, pretty much cup both hands with d20s...  My immunologist has a theory that every organ that they think doesn't have any particular function actually has to do with immunology, and he seems to be being proven right.  Tonsils, adenoids, etc.  They're all in there for a reason! So far in my immediate and extended family, it's had a 100% death rate: a cousin's husband infected and died.  In my circle friends, 0%: two friends infected, neither died.   At work, co-worker's grandfather infected and died, but was 75ish?  So overall, 50% fatal in my immediate and slightly extended circles.

[graydon]

Eek on the death rate. May no further ill things arise!

Hereabouts, we're two cases (me, probably, and my sister); I seem to have had about as mild a case as symptomatic cases get, while my sister's was rather worse. (She's recovered/recovering.)

Keeping all the appendages crossed!

[draconis]

Very cool! Thanks for sharing!

[thewayne]

You are welcome.  I found it quite fascinating.  I was interested in getting a newer watch that had the SpO2 sensor in case perhaps a declining level could be taken as an early indicator of COVID, but this seems to be a much better indicator and my watch already does it!

[silveradept]

That's interesting. Of course, that sort of detection is available to people who have bought those kinds of smart watches. Would be nice if that kind of detection were available for people who want smart watches, but don't necessarily want their fitness data being mined.

[thewayne]

Yeah, that is most certainly an issue.  Lower-end fitness devices in the Fitbit line can do this, but that info is still probably going to be mined, just at a lower out of pocket price point.  And, of course, the question of whether or not this sort of detection is going to be implemented and an alert available to the user.  I can look at my health data and see if my HRV seems to be getting less variable and go get myself tested because I don't that Apple has an alert watching for this.

[silveradept]

The thing that's really missing from all of this, I guess, is the app that doesn't actually mine any data and has the ability to talk to whatever watch you want to pair it with. It would be a really good, well-received application and I would really enjoy having such a thing.

[thewayne]

I have resigned myself to the fact that there's a huge amount of data about me that I have absolutely zero control over out there.  I would like to move to Europe so that I'd have at least a little.  We're never going to get something like the GDPR over here, there's too many monied interests.