[HN Gopher] Apple Watch Identifies SARS-CoV2 Infection and Predi...
       ___________________________________________________________________
        
       Apple Watch Identifies SARS-CoV2 Infection and Predicts Diagnosis
        
       Author : giuliomagnifico
       Score  : 170 points
       Date   : 2021-02-10 14:11 UTC (8 hours ago)
        
 (HTM) web link (preprints.jmir.org)
 (TXT) w3m dump (preprints.jmir.org)
        
       | vrc wrote:
       | This is basically how the WHOOP band works. Anyone with an Apple
       | Watch curious to see can find your tracked HRV in the Health App
       | on your iPhone.
       | 
       | However, looking at heart-rate (HR) itself will be misleading.
       | Big swings in HR or high HR in general usually misinterpreted as
       | having high HRV, when it's often the exact opposite. HRV is a
       | measure of the variability of 1/(inter-beat time). So it's
       | measuring the time-average of really small variations from a set
       | point.
       | 
       | And counterintuitively, HRV is usually highest when the
       | sympathetic (flight or fight) nervous tone and HR is lower. In
       | those situations, the parasympathetic control dominates, and
       | small wiggles caused by "noise on the wire" conducted directly to
       | the heart's pacemaker via the vagus nerve increases HRV. Often
       | times this is when HR is lower, and because higher HR or spikes
       | in HR are often caused by increased sympathetic tone, this leads
       | to a blunting of this "parasympathetic noise".
       | 
       | Source:
       | https://journals.physiology.org/doi/full/10.1152/physiol.000...
        
         | grok22 wrote:
         | Is there something else like the WHOOP band, but sold as a
         | standalone device (the WHOOP band is given free with a fitness
         | subscription service!)?
        
           | pmw wrote:
           | I've never had the WHOOP, but I use Apple Watch combined with
           | iPhone apps to track heart metrics. I recently discovered
           | AutoSleep and HeartWatch, which both track HRV along with
           | other metrics.
        
           | vrc wrote:
           | I track mine on my Apple Watch which records it in the Health
           | App. It's basic graph and I can download it if I want, but
           | I've found tracking day-over-day/week-over-week is a good
           | enough signal. For example, I did dry January this year and
           | practiced meditation every day since and I've seen a step-
           | jump up corresponding to that.
           | 
           | Still have to keep another record of external factors to
           | correlate with it, though. I've heard people finding success
           | with a 3p monitor and the Elite HRV app as well [0].
           | 
           | [0] https://elitehrv.com/
        
       | _nickwhite wrote:
       | _" Longitudinally collected HRV metrics from a commonly worn
       | commercial wearable device (Apple Watch) can identify the
       | diagnosis of COVID-19 and COVID-19 related symptoms."_
       | 
       | Having first-hand experience, I can confirm that my heart rate
       | was WAY up, and my pulse-ox was WAY down when the virus was at
       | its worst. I used the pulse ox value to make sure I was getting
       | in good breaths (and yes, I know there is a hefty margin of error
       | on these consumer devices.) I use a Garmin, but the sensors are
       | pretty much the same on Apple Watch.
       | 
       | It would be pretty easy for the device to tell I was _sick_ but
       | probably impossible to tell I had COVID-19 instead of the Flu or
       | a bad infection or maybe pneumonia.
        
         | mandis wrote:
         | umm speaking from personal experience (comparing garmin reading
         | with hospital oximeter), garmin is waaaay inaccurate sometimes!
         | Maybe it is because I always shower with it, or maybe it just
         | loses accuracy over time. Didnt give it a second thought and
         | just disabled the sensor.
        
         | joseph_grobbles wrote:
         | HRV is neither pulse rate or blood oxygen. It is variations
         | between heart rates, and the reason this is fascinating is
         | because HRV is a significant _leading_ indicator, long before
         | the other indicators which are lagging.
         | 
         | HRV is increasingly becoming a very important metric. When your
         | body is under stress (mental or physical) the heart because
         | tightly sequenced. Under normal, healthy conditions it has
         | slight lags and leads based upon breathing and other
         | conditions.
         | 
         | This post will be dead given that dang is a pathetic bitch and
         | a *horrid* moderator, but for those enlightened enough to use
         | showdead.
        
         | miskin wrote:
         | In my case HRV went down almost 30% before I started to have
         | symptoms with 50% of average on the worst day. Resting heart
         | rate went up 35% on the worst day and respiratory rate went up
         | 18%. But only HRV was obviously changed before I started to
         | feel symptoms and became infectious.
        
       | germinalphrase wrote:
       | I wish I could buy a watch that continuously monitored my
       | hydration levels. So many health concerns are directly impacted
       | by hydration.
       | 
       | Edit: My comment meant to recognize that while this tech doesn't
       | yet exist, it would be helpful as people end up in the hospital
       | all the time for medical problems that are exacerbated by
       | dehydration. Simply saying "drink water when you're thirsty" is
       | beside the point.
        
         | uncledave wrote:
         | Use the Apple Watch. It reminds you to stand up every hour. Go
         | pee then. If it's not clear then drink a glass of water. Works
         | for me.
        
           | germinalphrase wrote:
           | I don't really have a desk job, so a timed reminder wouldn't
           | be as useful to me as actual data.
        
             | uncledave wrote:
             | You've got sensors in your head and data when it comes out
             | of you. I do a hell of a lot of hiking and that's all you
             | need to monitor hydration.
        
               | Jtsummers wrote:
               | A lot of people have conditioned themselves to ignore the
               | signs of thirst or misinterpret them as hunger. Our,
               | largely, idle/still lives probably doesn't help here, as
               | staying at a survivable level (even if not a truly
               | healthy level) of hydration isn't hard if you're not
               | working up a sweat or in environmental conditions that
               | cause you to become dehydrated faster.
        
         | nradov wrote:
         | If you're thirsty then drink some water. We have no reliable
         | clinical evidence that drinking extra water when you're not
         | thirsty causes improved health.
         | 
         | So far no one has succeeded in building a reliable, wearable,
         | non-invasive hydration sensor.
         | 
         | https://www.dcrainmaker.com/2019/11/lvls-hydration-sensor-ri...
        
       | 2wrist wrote:
       | There have been a few cyclists who use whoop and it picked up on
       | HRV and they could see that something was not right.
       | 
       | Hopefully HRV gets added to the AWatch soon, if it isn't already.
       | (C'mon Apple, deliver my device!)
       | 
       | It is pretty cool that we can take these measurements and
       | hopfully make data driven decisions. Hopefully in time we can use
       | these measures to be prescritive and be guided to make better
       | decisions.
        
         | jjevanoorschot wrote:
         | Heart Rate Variability is already measured throughout the day
         | if you wear an Apple Watch. You can find the data in the Health
         | app.
        
           | ben1040 wrote:
           | Yep. It takes a sample every few hours, but you can also get
           | a HRV measurement on demand by running a session in the
           | Breathe app on the watch.
           | 
           | It doesn't tell you anything about HRV in the Breathe app or
           | that it took a new sample for you, but you'll find a new
           | entry in the Health app if you go look right afterward.
        
           | 2wrist wrote:
           | thanks for that! I wasn't sure.
        
       | victor106 wrote:
       | Slightly OT:-
       | 
       | I really hope Apple Watch SPO2 is more accurate.
       | 
       | The current version is not accurate enough to use as a
       | replacement for a pulse oximeter
       | 
       | https://www.medpagetoday.com/blogs/skeptical-cardiologist/88...
        
         | whoisburbansky wrote:
         | Agreed, but the article is about using HRV, not spO2
        
           | victor106 wrote:
           | Agreed, This is tangential to that article.
        
             | whoisburbansky wrote:
             | Follow up that for most diagnostic purposes, you don't
             | really care about the specific spO2 precentage beyond "is
             | it below 90" or not, for which the Apple Watch is perfectly
             | satisfactory: https://tidbits.com/2020/10/22/the-
             | paramedics-guide-to-blood...
        
       | screamingninja wrote:
       | Title is misleading IMO. The study has nothing specific to do
       | with Apple Watch. They mentioned that they used "a commonly worn
       | commercial wearable device (Apple Watch)" for testing. Any device
       | with continuous heart rate monitoring will do.
        
         | Abishek_Muthian wrote:
         | Considering the proliferation of fake pulse-oximeters due the
         | pandemic, it might be easy to go for Apple Watch if one can
         | afford it and have access to it.
         | 
         | I got a FDI approved pulse-oximeter accidentally from
         | Amazon(US)[1] after realizing almost every pulse-oximeters sold
         | online where I live were making false claims[1].
         | 
         | [1] https://abishekmuthian.com/testing-fda-approved-pulse-
         | oximet...
        
           | yoz-y wrote:
           | Note though that the study does not use (or even mention) the
           | oximeter. They use heart rate variability.
           | 
           | Edit: They probably also used the older model as the study
           | was submitted in November and the Apple Watch with oximeter
           | came out in September, and was seriously supply constrained.
        
         | zepto wrote:
         | They know the Apple Watch works.
         | 
         | They haven't tested _any_ other devices.
         | 
         | This _is_ about the Apple Watch.
         | 
         | Your comment is supposition. Likely correct, but not
         | guaranteed.
        
           | screamingninja wrote:
           | > Your comment is supposition. Likely correct, but not
           | guaranteed.
           | 
           | No, the paper was very clear that Apple Watch was used to
           | measure Heart Rate Variability (HRV). There is absolutely no
           | mention of any unique advantages that Apple Watch provided in
           | the given scenario. The study is about using the HRV data
           | from a wearable device to identify indicators of COVID-19; it
           | is not an endorsement or an advertisement for Apple.
        
             | zepto wrote:
             | It doesn't matter.
             | 
             | Have you compared the HRV data from different devices? Have
             | you compared the Apple HRV data and the data from other
             | devices to a reference instrument, or confirmed that it
             | meets some standard?
             | 
             | The Apple Watch _is_ the reference instrument for this
             | paper. It would be a scientific _error_ to conceal that
             | fact.
             | 
             | This isn't about product endorsements, it's about saying
             | what laboratory equipment was used so that other scientists
             | don't have hidden confounds when they attempt to replicate.
        
               | screamingninja wrote:
               | > The Apple Watch is the reference instrument for this
               | paper.
               | 
               | Exactly. It is an instrument used to gather metrics. The
               | study is about analyzing the metrics and not so much
               | about the tools used to gather those metrics. Read the
               | paper's title.
        
               | zepto wrote:
               | The Apple Watch is mentioned 27 times in the paper.
               | 
               | No other HRV instrument is mentioned.
               | 
               | Also, I recommend looking into how the scientific method
               | works.
               | 
               | Generally if you don't have a standardized instrument,
               | you must say what instrument you used.
               | 
               | If they said "HRV sensors can _in general_ detect covid",
               | they would be making a claim _not supported by their
               | results_.
               | 
               | You seem desperate to not have Apple's name associated
               | with this paper, but it would be unscientific not to name
               | it.
               | 
               | Good scientists are careful not to make generalizations
               | they can't support with evidence or references.
        
               | screamingninja wrote:
               | > It would be a scientific error to conceal that fact.
               | 
               | Who said anything about concealing any facts?
        
               | zepto wrote:
               | > Title is misleading IMO. The study has nothing specific
               | to do with Apple Watch. They mentioned that they used "a
               | commonly worn commercial wearable device (Apple Watch)"
               | for testing.
               | 
               | The title is factual and not misleading. It seems like
               | you want it changed to remove a fact.
               | 
               | > Any device with continuous heart rate monitoring will
               | do.
               | 
               | This is something you assert, is definitely not a
               | conclusion of the study, and _is misleading_.
        
       | aorth wrote:
       | Offtopic: what is up with this website? I just clicked the link
       | and noticed that Firefox downloaded the paper's PDF 55 times
       | automatically before I closed the window!
        
         | kristjansson wrote:
         | It gets points for being a novel form of broken!
        
       | sebmellen wrote:
       | This reminds me of a great interview with two ER doctors on
       | Amanpour (PBS) two weeks ago. Pulse oximeters can be used to help
       | detect which patients need hospitalization _before they
       | themselves notice_ , with astounding results.
       | 
       | I really recommend the episode:
       | https://www.pbs.org/wnet/amanpour-and-company/video/how-earl...
       | 
       | Here's another article on a hospital implementing the early
       | monitoring program
       | https://www.nny360.com/news/publicservicenews/samaritan-util....
       | 
       | > _With the oximeter, Samaritan is asking patients to keep track
       | of its measurements twice a day and to write the readings down.
       | Then Home Health follows up with telehealth visits, either over
       | the phone or via Zoom on days two and four, as well as days seven
       | and 10._
        
         | vvram wrote:
         | This has been standard practice in India for a while now
         | https://mumbai.apollohospitals.com/covid-19-update/stay-i-at...
         | Package includes oximeter, test sample collection, PPE supplies
         | and optional food drop off. Includes a zoom cal with
         | nurse/doctor at regular touchpoint intervals to facilitate
         | hospitalisation
        
         | pkaye wrote:
         | I would say thought that if your hands are cold, warm them up
         | before you take a pulse oximeter reading.
        
         | danesparza wrote:
         | This is happening now in hospitals with Covid-19. I know,
         | because I'm married to a nurse. Nurses call them "happy
         | hypoxics" because they have no idea their SPO2 levels are
         | dangerously low -- but a pulse oximeter clearly indicates they
         | need additional oxygen.
        
           | treeman79 wrote:
           | I had a pulmonary embolism's was white as a ghost struggling
           | to breathe and that dang meter said everything was fine. Even
           | the bloodwork at the hospital said everything was fine. Lost
           | some lung over that and took a year to recover.
        
             | graeme wrote:
             | Different use case: here you can have someone with covid
             | with no perceptible symptoms but low blood o2 tells doctors
             | it is an emergency.
             | 
             | Whereas presumably you had some symptoms that were ignored?
        
               | lostlogin wrote:
               | A negative D-dimer in someone with a PE sounds rare - the
               | test has a negative predictive value of 95.7%.
               | 
               | I'm guessing that OP managed to complain enough or be
               | sick enough (but with normal O2 sats?) to get a CT.
               | 
               | https://www.sciencedirect.com/science/article/abs/pii/S07
               | 364...
        
               | treeman79 wrote:
               | D timer was normal. I was told it was muscle strain. They
               | ran an X-ray to be safe. Just after they rushed me to get
               | a CT. I was admitted.
               | 
               | Fun times.
               | 
               | Turns out I have factor 5 Leiden, I clot like crazy
        
             | nradov wrote:
             | You might have been going into shock. A pulmonary embolism
             | can block blood flow to part of a lung and kill that tissue
             | but it won't necessarily cause SpO2 to drop much. Patients
             | who are otherwise healthy have extra lung capacity to
             | spare.
        
               | treeman79 wrote:
               | Sounds reasonable. It was only one lung that had a clot.
               | Heart was racing for months Afterwards
               | 
               | Walk 30 feet. 170bpm for ten minutes.
        
         | atc wrote:
         | My brother had fairly severe COVID-19 symptoms -- fatigue,
         | feaver, very bad chest -- and he was sent home from hospital
         | due to there not being any beds (and him not being serious
         | enough a case I suspect) with the instruction to monitor his
         | blood oxygen through an Oximeter as you suggestion: e.g. "95
         | for > 30 mins and you should come back."
        
         | linuxftw wrote:
         | More than 2 doctors have reported positive effects with certain
         | drugs to treat the infection, but those people are lambasted.
         | What makes this anecdotal evidence any different? Shouldn't we
         | report this as misinformation since it didn't come from an
         | approved source such as the CDC or WHO?
        
           | sebmellen wrote:
           | I think it's definitely more than anecdotal! Take a look at
           | the video -- they're running large trials at a number of
           | hospitals already.
           | 
           | And I think the two doctors share your same gripe, expressing
           | frustration at the CDC not taking action to recommend these
           | steps earlier.
        
         | nradov wrote:
         | The current clinical recommendation for ambulatory COVID-19
         | patients at home is to go to the hospital if the pulse oximeter
         | reading drops below 94%. Accurate pulse oximeters are cheap now
         | so it's a good item to keep in your home first aid kit.
         | 
         | https://covid19criticalcare.com/i-mask-prophylaxis-treatment...
        
           | [deleted]
        
           | thebean11 wrote:
           | Mine frequently drops to the low 90s (or even 80s) based on
           | the Apple watch, despite normally being 98-100. I'm certainly
           | not in good shape, but still, should I be worried?
        
             | sp332 wrote:
             | Well I don't think it sounds like Covid-19 specifically,
             | but it wouldn't hurt to get that checked out. It's not
             | something that happens to most people, if that's what
             | you're asking.
        
             | nradov wrote:
             | Wrist devices are generally not very accurate. I mean they
             | can be accurate under ideal conditions, but if you're
             | moving around a lot or sweating or the band is loose or you
             | have dark or hairy skin then you might get a low reading.
             | Better to use a real pulse oximeter that clips onto your
             | finger. They're cheaper than an Apple Watch.
        
               | bobthepanda wrote:
               | Wasn't there also a thing with the finger oximeters as
               | well?
               | https://www.nytimes.com/2020/12/22/health/oximeters-
               | covid-bl...
        
       | hobom wrote:
       | I am kind of jaded, but despite the interesting approach, I
       | predict that this research will not end up being deployed in time
       | to make any difference. The real world pipeline just takes too
       | long.
        
       | 14 wrote:
       | This does not surprise me one bit. I have a child and every time
       | he gets sick his heart rate rises. The last time I noticed the
       | heart rate first and called his mom telling her I think he is
       | getting sick. The next day he had a fever.
        
       | pintxo wrote:
       | Now, will Apple add this as a feature?
        
         | soco wrote:
         | For a healthy price premium.
        
           | Jtsummers wrote:
           | I get that it's cool to ridicule Apple, but maybe pick
           | something they've actually demonstrated a tendency to do in
           | the past? In the case of health features on their Watch
           | they've been pretty consistent about just making it available
           | if the Watch has the right sensors (so older watches don't
           | get all the new features because they lack some of the
           | necessary sensors).
        
       | freitasm wrote:
       | Apple Watch and any other HR monitoring watch...
        
       | sschueller wrote:
       | https://news.ycombinator.com/item?id=26079918
        
       | joshdick wrote:
       | It's crazy to think that a tech company like Apple might have the
       | clearest picture of the pandemic
        
         | james_pm wrote:
         | Amongst rich people with Apple Watches, maybe.
        
           | benbristow wrote:
           | Hardly need to be rich to have an Apple Watch, they're not
           | that expensive for a tech product really.
        
         | bilekas wrote:
         | I don't think it's specific for apple, they did mention that
         | the participants just had the apple watch, but from the sounds
         | of it, any GPS hear rate monitor would help..
         | 
         | I think Maybe a collective app simular to Strava might be a
         | better place to get a collection of data maybe..
        
           | eli wrote:
           | The Oura "smart ring" maker claims it can detect early Covid
           | from variations in temperature
           | https://www.fiercebiotech.com/medtech/oura-study-shows-
           | its-s...
        
             | miskin wrote:
             | Oura was quite good with warning me that something is not
             | ok and I should take it easy on the morning of the day when
             | I started to have symptoms. I was tested positive later
             | that day. Interestingly, nobody I met days before I was
             | warned was infected, so in my case warning came in right
             | moment.
        
             | Jtsummers wrote:
             | I was going to mention them. Some members of the US
             | military were given them as part of a study on COVID
             | detection. Basically any wearable sensors covering the
             | right metrics can be used for this. The question, really,
             | was less about "Can wearable health monitoring equipment
             | detect early signs of <disease>?" than "What are the early
             | signs which wearables can detect and use for prediction
             | once we know them?"
        
       | stuartbman wrote:
       | So some big limitations, speaking as a doctor. Firstly, I'm
       | surprised that they allowed watches on the ward. They're a huge
       | infection risk and most places are bare below the elbows (NHS),
       | moreso for covid. Secondly, they only looked at symptomatic covid
       | cases (1 day before symptoms started was their prediction as far
       | as i can tell. This is completely useless as the 24hrs before
       | symptoms start the patient is likely to already be highly
       | infectious, and misses the asymptomatic carriers which have an
       | indeterminate effect on spread as well. Far better to use the
       | semi-proven (but equally controversial) lateral flow tests and
       | avoid these risks. In the UK, hundreds of healthcare staff have
       | been identified as covid+ >48hrs before symptoms in this way.
        
         | nradov wrote:
         | For reducing infection risk one option is to keep the watch in
         | a pocket while working on the ward and wear a separate wireless
         | heart rate monitor on the chest or upper arm. I don't think
         | they did that in this study, just pointing it out as an option
         | for healthcare workers who want to track their HRV on the job.
        
         | tinus_hn wrote:
         | You state:
         | 
         | > they only looked at symptomatic covid cases
         | 
         | Which means the study cannot be used to prove or disprove this
         | claim:
         | 
         | > and misses the asymptomatic carriers
         | 
         | Why is there such a need to hastily dismiss any potential
         | improvement?
        
         | ggm wrote:
         | it is not unheard of for something at level x to be developed
         | to level 2x so if it can do 24h now, with higher sample rate
         | and better maths, what if it got to 48h in tractable time?
         | 
         | to the watch-in-a-ward point: valid. But, if this technique did
         | get to 48h+ predictive quality, and was available to wearers of
         | smart watches _outside of wards_ would you still have hesitancy
         | to consider it useful?
        
         | rgbrenner wrote:
         | Speaking as a non-doctor, I don't have any lateral flow test
         | supplies or equipment. Do they sell that on Amazon?
         | 
         | But seriously, a test I don't have easy access to is not an
         | alternative. A lateral flow test has no predictive value to me
         | because I'm never going to get one before I'm actually sick.
        
           | sveme wrote:
           | Lateral flow tests are rapid test kits to my understanding,
           | so they should be available on Amazon if accepted by your
           | local medical devices authority.
        
           | yread wrote:
           | On the other hand Apple Watch costs like 400$ and UK just
           | bought 400M lateral flow tests for 1.3Bn pounds
           | 
           | https://www.bmj.com/content/372/bmj.n287
           | 
           | Or you can buy it online for 250$/10 tests (if you can
           | swallow that you're being fleeced this much)
        
           | zamfi wrote:
           | > But seriously, a test I don't have easy access to is not an
           | alternative.
           | 
           | Do you have access to the custom Apple Watch app they used
           | here? I don't either.
           | 
           | Health authorities could make either of these available to
           | the general public -- the parent poster is making a comment
           | about which is more valuable under the assumption of access.
           | 
           | You're not wrong, a test you don't have access to obviously
           | has no predictive value for you, but right now we (the
           | public) have access to neither, so this isn't a
           | distinguishing factor.
           | 
           | Now, if you're making the argument that the Apple Watch app
           | would be _easier_ to distribute, then you can read the parent
           | 's criticism as "sure, but only knowing _after_ you 've
           | potentially spread it is not very useful."
        
             | kelnos wrote:
             | > _Do you have access to the custom Apple Watch app they
             | used here? I don 't either._
             | 
             | That's pretty immaterial when discussing theoretical
             | effectiveness. Obviously, getting wide use depends upon it
             | getting packaged up into an app listed on the app store,
             | and some sort of awareness push.
             | 
             | That needs to be done once, by the app's authors. For
             | lateral flow tests, to have similar effectiveness, that
             | means that literally every Apple watch wearer (just to
             | assume a similar population size) needs to get themselves a
             | supply of tests (and keep getting new tests when they run
             | out), and remember to perform the test every day. That is a
             | _much_ higher hurdle to jump than getting this app onto
             | people 's watches (assuming their study is correct and can
             | be independently verified!). I also expect the supply of
             | test kits is not robust enough to handle that kind of
             | demand.
             | 
             | > _Now, if you 're making the argument that the Apple Watch
             | app would be easier to distribute, then you can read the
             | parent's criticism as "sure, but only knowing after you've
             | potentially spread it is not very useful."_
             | 
             | Reducing spread potential by 24 hours when you've perhaps
             | been spreading it for a week already isn't exactly a game
             | changer, but it's still useful, especially if the only
             | thing people have to do is install an app on their watch.
             | Expecting everyone to obtain rapid test kits and test
             | themselves daily is in general a non-starter.
        
             | nostromo wrote:
             | The data is all readily available in the default Apple
             | health app.
             | 
             | Yes, to make these same predictions you'd have to do some
             | statistics as described in the paper, but no special app is
             | required.
             | 
             | (And that's why this finding is interesting: they have the
             | data available from patients before they were sick, because
             | every new Apple Watch records this data out of the box.)
        
               | zamfi wrote:
               | Yes, the finding is definitely interesting because it
               | suggests that we could make this available very broadly
               | (i.e., anyone with an appropriate Apple Watch) without
               | needing to ship a bunch of hardware.
               | 
               | But the limitations are worth noting: you may already
               | have infected people by the time this detects your
               | illness. That isn't true for lateral flow tests, making
               | the latter more useful as a preventative testing tool
               | (again, in the absence of access differences).
               | 
               | However, I don't understand what you're trying to say
               | with this claim:
               | 
               | > Yes, to make these same predictions you'd have to do
               | some statistics as described in the paper, but no special
               | app is required.
               | 
               | "Do some statistics" is approximately as impossible as
               | "order lateral flow test reagents" to the general public
               | -- a consumable version of either the process described
               | in this paper, or the lateral flow kits mentioned
               | earlier, needs to be produced by someone skilled here, in
               | order for this to be useful to the general public.
        
         | kelnos wrote:
         | Getting a warning 24 hours "early" that you might be infected
         | is still useful. Perhaps in that 24 hours you were going to
         | make a grocery trip and potentially infect a bunch of people,
         | but now you won't because you got that early warning.
         | 
         | Claiming that something is useless because it doesn't cover
         | _all_ cases seems a little weird to me. It 's a tool in the
         | toolbox that can reduce the possibility of spread in a limited
         | set of cases.
         | 
         | Using lateral flow tests requires everyone to purchase a big
         | supply of them and use one every day. This watch-based warning
         | just requires you to have an Apple watch and run a new app on
         | it (which I hope they'll make publicly available), and it'll
         | just let you know without any extra action taken. Your average
         | Apple watch user is probably pretty likely to take the simple
         | step of installing a new app; they're not going to buy a supply
         | of lateral flow tests (which they probably don't even know much
         | about or haven't even heard of) and test themselves every day.
        
           | rimliu wrote:
           | Yup. I was lucky the person whom I contracted COVID from
           | informed me the moment they got the test result. I was on my
           | way to work, just about to leave the car. Turned around and
           | went back home. Developed symptoms the same evening. It was a
           | lucky coincidence that was Monday so I've stayed home the
           | whole weekend and had no contacts for a couple of days I was
           | likely already infectious. (The person I got it from only
           | developed symptoms two days after our contact). People who do
           | contact tracking only on Wednesday. So my contact informing
           | me saved three days worth of my potential contacts from
           | getting COVID from me.
        
         | Closi wrote:
         | > This is completely useless as the 24hrs before symptoms start
         | the patient is likely to already be highly infectious, and
         | misses the asymptomatic carriers which have an indeterminate
         | effect on spread as well.
         | 
         | Nothing is a one-shot-solve-all solution to Covid. If Apple
         | watches can detect it and prompt people to go get a full test,
         | that's great. I've got an ongoing theory that a lot of the
         | spread is by people who ignore their symptoms because 'they
         | have a cough but it's not a _covid_ cough' or 'they haven't
         | lost their smell so it _can't be covid_ ' so the more things
         | that can prompt you to get a test and isolate the better.
        
         | diebeforei485 wrote:
         | Why are watches an infection risk?
        
           | BitwiseFool wrote:
           | I assume it's because they accumulate crud and bacteria. You
           | can wash your hands but you never really wash your watch. I
           | also assume that because it's on your wrist every time you
           | scratch your body or touch your face the bacteria covered
           | watch deposits something icky on contact.
        
       | eightysixfour wrote:
       | Oura Ring also ran a study on this (which I was a part of). It is
       | interesting because in 2019 I had a severe cold and the Oura Ring
       | gave me a very low "Readingess" score in the 2 days leading up to
       | it, despite me feeling fine and getting good sleep. I had never
       | had readiness scores so low prior to that or since, so I don't
       | believe it was any sort of confirmation bias.
       | 
       | Quantified health is going to bring about some amazing QOL
       | improvements that we're still only beginning to understand and it
       | is one of the areas I am most bullish about for sure.
        
       | bilekas wrote:
       | This sounds great, I am going through the PDF, there's a LOT
       | there..
       | 
       | But I'm not sure how reliable that it would be just to track the
       | position (possible infection radius to known area) And the heart
       | rate variability.. Its interesting though! Certainly every little
       | helps..
        
       | auslegung wrote:
       | Is there anything actionable for us, today, in the study? I'm not
       | skilled in reading these, I read the first few paragraphs and
       | knew I was over my head.
        
       | blakesterz wrote:
       | Ineresting. So... Prior to the diagnosis of COVID-19 by nasal
       | PCR, significant changes in heart rate variability (HRV), were
       | observed demonstrating its predictive ability to identify
       | COVID-19 infection.
       | 
       | So in theory watching your heart rate closely you should be able
       | to see it coming?
       | 
       | (I tried to figure out exactly what to watch for and how to
       | measure it, but couldn't figure it out, hopefully someone else
       | can explain if anyone with a watch could do this)
        
         | whoisburbansky wrote:
         | The measure they're talking about, HRV, is measuring variance
         | of the peak to peak and trough to trough between successive
         | heartbeats. Individual heartbeats are on the order of one or
         | two a second, but are remarkably consistent, so this
         | measurement of variance is usually on the order of
         | milliseconds.
         | 
         | Healthy ranges are, vaguely speaking, above 80ms, with
         | unhealthy ranges being much lower, the idea being that when
         | you're sick or stressed, your heart rate control falls back to
         | the nervous system since your brain has other things to deal
         | with, making your heartbeat more consistent, which means lower
         | variability. This is generally not great because you want to be
         | able to switch up the spacing between beats on the fly for
         | better efficiency, kind of like switching gears on a car.
         | 
         | All of this is to say that the measurement they're talking
         | about is pretty tiny and you're unlikely to be able to measure
         | it accurately manually.
        
           | t-writescode wrote:
           | > Healthy ranges are, vaguely speaking, above 80ms
           | 
           | I'm not sure what's being said here is safe or appropriate.
           | If you're doing nothing, your heart rate variance won't
           | likely change. There's also very little that matters about
           | it, just normals, for you.
           | 
           | Every Google Search I've ever done on HRV has turned up that
           | fact: HRV is incredibly personal and personal trends matter
           | the most.
           | 
           | From my own experience, my HRV is low when I'm not doing
           | anything - and why wouldn't it be? I'm not _doing_ anything.
           | I have no need for sudden changes when I'm typing on a
           | keyboard.
           | 
           | Further, you can be as healthy as a marathon runner and have
           | very low HRVs.
        
             | andor wrote:
             | " _From my own experience, my HRV is low when I 'm not
             | doing anything - and why wouldn't it be? I'm not _doing_
             | anything. I have no need for sudden changes when I'm typing
             | on a keyboard._"
             | 
             | It's not about whether you "have a need for sudden changes"
             | or not, but whether the sympathetic or the parasympathetic
             | nervous system has the upper hand. There are many reasons
             | for why it could be one or the other, but they are usually
             | roughly summarized as "physical or mental stress".
             | 
             | For instance, when you sit at your keyboard and respond to
             | someone who is wrong on the Internet, that is likely to
             | cause negative emotions and mental stress. This would
             | increase sympathetic nervous system activity and as a
             | result lower your HRV.
             | 
             | " _Further, you can be as healthy as a marathon runner and
             | have very low HRVs._ "
             | 
             | Marathon runners are not always equally healthy. They also
             | get sick or stressed sometimes, and quite often they are
             | under physical stress due to training a lot. That's why
             | some of them observe HRV to get an indication of their
             | readiness for high intensity training or competitions (e.g.
             | Whoop, Garmin Recovery Advisor).
             | 
             | That means, just sitting at their keyboard their HRV could
             | be high or low, depending e.g. on how well they recovered
             | from a hard training run.
        
         | ryanmarsh wrote:
         | Increased heart rate with decreased SpO2 commonly precedes
         | diagnosis of respiratory infection. Increased heart rate alone
         | is often seen as a warning to run pathology labs before
         | beginning chemotherapy which can destroy neutrophils. Something
         | you don't want to do if the patient is in the beginning stages
         | of an infection.
         | 
         | I'm not a doctor I've just been around this stuff more than I
         | wish to. Frankly I wish the Apple watch was more aggressive in
         | reporting anomalies to the user. Something as simple as "we
         | noticed your heart rate always increases at this place and
         | time" can make the user aware that something is wrong in their
         | life... assuming it's not a gym.
        
         | bilekas wrote:
         | That would make me nervous, which would mess up my heart rate..
         | :)
        
       | secretsatan wrote:
       | Surely more than 1 condition can cause heart rate changes? Is
       | there a pattern they can match, or is it the most likely cause?
        
         | pwinnski wrote:
         | From my reading, many respiratory illnesses can cause these
         | symptoms, but right now if you have a respiratory illness at
         | all, odd are it's COVID-19, so it's worth at least getting a
         | PCR test. And if it's not that, you have a very serious flu or
         | something which probably requires treatment as well.
        
           | miskin wrote:
           | You are right, I had similar data and same warning as I got
           | for COVID-19 from Oura cca year ago with regular flu. It is
           | now more important because of COVID-19, but it is also very
           | helpful for any similar illness that one may spread.
        
         | l33tman wrote:
         | There are lots, as what you really are measuring are subtle
         | variations in the sympathetic and parasympathetic drives of the
         | heart by the autonomous nerve system. This can get affected by
         | lots of things, a quick googling provided dozens of completely
         | different papers looking it stuff like heart disease itself,
         | but also clinical depression etc.
        
       | IgorPartola wrote:
       | Whatever happened with the MIT cough analyzer? That seemed like
       | really promising tech that just kind of fell off the news feeds
       | and was never mentioned again. I thought they were trying to
       | apply for an FDA approval. Latest info is 47 days old:
       | https://www.bbc.com/news/technology-54780460?fbclid=IwAR1bGR...
        
       ___________________________________________________________________
       (page generated 2021-02-10 23:02 UTC)