[HN Gopher] Study uses wearables to show that physical activity ...
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       Study uses wearables to show that physical activity lengthens REM
       latency
        
       Author : gmays
       Score  : 87 points
       Date   : 2024-04-02 17:58 UTC (5 hours ago)
        
 (HTM) web link (news.utexas.edu)
 (TXT) w3m dump (news.utexas.edu)
        
       | jeffbee wrote:
       | I tried wearing my Garmin to bed for a while, but the information
       | just wasn't that interesting. I can see where science gets value
       | out of a population study but for the N=1 population consisting
       | of yourself, I just wasn't seeing the point.
        
         | creaghpatr wrote:
         | I enjoyed getting the metrics (not sure how accurate they were)
         | but my garmin is so clunky it's impossible to sleep in. Great
         | for everything else.
        
           | jeffbee wrote:
           | I wear the women's model of the smallest one they make for
           | this exact reason. Most of the watches Garmin is making are
           | just ridiculously big.
        
         | phildenhoff wrote:
         | On the contrary, I've been wearing my Apple Watch nearly 24
         | hours a day for a few years and find the sleep info extremely
         | useful.
         | 
         | Really, the primary benefit I get is twofold:
         | 
         | 1. I know approximately how long I slept for and remind myself
         | of that all day via a widget. A short sleep is common for me,
         | but I end up feeling foggy. Being reminded that it's OK, I had
         | a poor sleep, helps ease my mind.
         | 
         | 2. I see approximately when I fell asleep and when I woke up. I
         | end up having to add extra time if I sleep past my alarm, but
         | seeing that I didn't really fall asleep until late into the
         | night helps me manage the pattern of late nights.
         | 
         | Both of those are easily covered by even semi-diligently
         | tracking your sleep on paper, but having my watch do it for me
         | is what I like!
        
           | ScoobleDoodle wrote:
           | > I end up having to add extra time if I sleep past my alarm
           | 
           | I find this one a painful design decision on the Apple team's
           | part. The end time of the normal desired sleep schedule does
           | not mean the literal end of sleep every day. I wish they
           | wouldn't clip the data at the end of the sleep schedule.
           | Maybe it's because they're using heuristics and so all the
           | data is guesstimates?
        
             | ra7 wrote:
             | I find the Autosleep app to be much more accurate than the
             | Watch's native sleep tracking.
        
           | wiredfool wrote:
           | Mine was absolute crap at sleep detection. Typically it would
           | report that I fell asleep before I went to bed, or I was
           | asleep longer than I was in bed.
           | 
           | Heart rate detection and so on was generally fine through the
           | night, as was Hrv. I sort of wonder if the actual sleep
           | detection is done on the phone, and if the phone is not
           | nearby, it just fails. (My phone doesn't go to the bedroom.
           | Makes it far easier to actually sleep)
           | 
           | (Also, Watch is dead now, and didn't replace it, so I might
           | be misremembering the exact bits, but the results were
           | generally paradoxical)
        
         | _qua wrote:
         | I used to be someone who might have a single beer with dinner a
         | few nights per week. When I got a Garmin and saw what it did to
         | my stress levels and sleep, I essentially stopped drinking at
         | all except for rare social situations.
         | 
         | In addition to improving the numbers, I noticed a qualitative
         | improvement in my sleep, energy levels, and exercise recovery.
        
           | esel2k wrote:
           | What are measurements for stress levels? Are they accurate
           | enough?
        
             | p_j_w wrote:
             | I may be wrong, but I think it's just heart rate and heart
             | rate variability.
        
             | occz wrote:
             | I find that I can pretty consistently see an increase in
             | resting heart rate by several beats per minute the day
             | after drinking, an elevated skin temperature and a
             | reduction in Deep- and REM-sleep. Particularly heavy
             | drinking will manifest itself as a large drop in heart rate
             | variability.
        
             | nradov wrote:
             | Garmin wearable devices display a proprietary stress metric
             | from their Firstbeat Analytics subsidiary. This is
             | basically just heart rate variability (HRV) normalized to
             | the user's baseline.
             | 
             | https://www.firstbeatanalytics.com/en/features/all-day-
             | stres...
             | 
             | As for accuracy, compared to what? Any definition of
             | "stress" is inherently somewhat arbitrary and subjective.
             | There seems to be a decent correlation to how I'm feeling.
             | But the metric isn't really actionable for most people.
        
             | jurassicfoxy wrote:
             | Whether the measurements are accurate enough is not clear,
             | but they are certainly precise enough. I (and all my
             | friends) can easily see huge differences in HRV on nights
             | of drinking, it's pretty amazing.
        
           | Aromasin wrote:
           | I had the same experience. It puts things into circumspect
           | when you can physically see how erratic things like heart
           | rate and sleep stage times differ with just a single drink.
           | The difference for my was so stark you'd think it were a bug
           | if it weren't for the fact I could spot the pattern and test
           | to see the truth of things.
        
             | jeffbee wrote:
             | OK but once you've learned this fact (that I think you
             | could have learned from numerous sources without any
             | technology), what is the ongoing value of the sleep
             | tracker? I feel it is in the category of things that you
             | learn from but then stop needing, including a cadence meter
             | on a bicycle, bathroom scales, and similar devices.
        
         | DefineOutside wrote:
         | I find my Apple Watch information useful. I don't remember when
         | I fell asleep but my apple watch does. This keeps me honest
         | about going to be too late.
         | 
         | Additionally, when I first got it, I found that I was only
         | getting 40 minutes of deep sleep which is why I was always
         | somewhat tired. After adding magnesium to my diet I am getting
         | around 70 minutes of deep sleep. I wouldn't have been able to
         | pinpoint this without the data. The apple watch is the best
         | sleep tracker [1] so your data might be too noisy to find
         | results.
         | 
         | [1] https://youtu.be/LPqtfC70QTU?si=6tTayfNCkcJwDayW&t=12m30s
        
           | greymalik wrote:
           | Does Watch accurately capture when you fell asleep, as
           | opposed to when you lay down and stopped moving?
        
             | DefineOutside wrote:
             | Not that well. You have to extrapolate from when the first
             | first deep sleep occurs in comparison to other nights.
        
         | aaronrobinson wrote:
         | It is interesting but I find Garmin data completely unreliable.
         | For example, it claims I'm awake for 2-3 times each night for
         | 30 minutes or more, it claims I'm asleep when I know I was on
         | Tik Tok because I couldn't sleep.
        
         | pedalpete wrote:
         | I had the same experience when I first started sleep tracking
         | before beginning our start-up https://affectablesleep.com.
         | 
         | My oura would tell me I didn't get enough deep sleep, or REM
         | sleep, and I was like - so what? What do I do with that
         | information?
         | 
         | We're using auditory stimulation to increase the efficiency of
         | deep sleep during the night. The data after a night of sleep is
         | less valuable than the real-time intervention.
        
       | dsalzman wrote:
       | This is one of the great "no shit" type studies. Good to validate
       | basic and ancient wisdom I guess.
        
         | phildenhoff wrote:
         | First you validate the no shit, and then you can ask why!
        
           | hattmall wrote:
           | lol, the why is also no shit too though in this case....
           | because you are tired.
        
         | abdullahkhalids wrote:
         | Some sequence of studies are not meant to validate that an
         | effect exists, but to quantify the size of the effect. And the
         | size of the effect under varying circumstances.
        
         | shawnz wrote:
         | What? Exercise decreasing the proportion of sleep spent in the
         | REM phase is "basic and ancient wisdom"?
         | 
         | Exercise improving sleep quality, sure, but this study is
         | saying something much more specific than that
        
           | 0xcde4c3db wrote:
           | From this study I don't think it's even clear why or under
           | what conditions higher REM latency is better, or that
           | increasing it in an individual can necessarily be considered
           | an improvement.
           | 
           | (I also don't think that's what the study was for; I think
           | they were mostly trying to validate the methods against
           | established results.)
        
       | kingrazor wrote:
       | This doesn't surprise me. A personal anecdote: a couple of years
       | ago I traveled to Japan for the first time. During my time there,
       | I walked much, much more than I usually do. As a result, I was
       | physically exhausted at the end of each day, and had some of the
       | best sleep I've had in years.
        
         | fkkffdddd wrote:
         | If you're missing that now - perhaps a great opportunity.
        
       | busymom0 wrote:
       | Personal anecdote: when strength training, I find that I have the
       | best sleeps on the night and second night after I do a session of
       | heavy farmer walks/carries. They are one of the most exhausting
       | exercises for me and great sleep is a good reward.
        
       | alwayslikethis wrote:
       | Wrist watches can't really detect sleep stages. That requires at
       | least an EEG to do reliably. The best they can do is maybe
       | distinguish between sleeping vs awake. The only consumer device
       | with an EEG is the Zeo, unfortunately they went bankrupt and
       | people are unable to distinguish the flukes from the real ones.
       | 
       | https://pubmed.ncbi.nlm.nih.gov/25991187/
        
         | cassianoleal wrote:
         | There was the Dreem 2 as well but they have also ended
         | production.
        
         | magicalhippo wrote:
         | Heh my SO just showed me her Garmin-something tracker log the
         | other day, and it showed her having an hour of deep sleep when
         | she'd been lying on the couch watching TV.
         | 
         | It's also showing various sleep stages whens he knows she's
         | been awake, trying to sleep.
        
           | chimeracoder wrote:
           | > It's also showing various sleep stages whens he knows she's
           | been awake, trying to sleep.
           | 
           | To be fair, people actually aren't that great at detecting
           | when they (or others) are really sleeping. Especially for
           | one's self, it's common to believe that you spent more of the
           | night tossing and turning than you really did, when in
           | reality you actually got some light sleep sprinkled in those
           | periods.
           | 
           | That said, consumer-grade wearable devices are demonstrably
           | not great at this either.
        
           | drewg123 wrote:
           | I love Garmin watches for many reasons, but their sleep
           | tracking is horrible. Even my ancient MS Band did a better
           | job than my Garmin Fenix 6
        
             | jurassicfoxy wrote:
             | It's pretty awful. Though they seem to be capable of
             | detecting terrible sleep, at least. Gotta love a 40 sleep
             | score night.
        
               | drewg123 wrote:
               | Agreed. But it can't tell if I'm jet-lagged and I wake up
               | 3 hours into my sleep at 2:30 am and lay there still, yet
               | unable to get back to sleep. That is sometimes an 80
               | sleep score night, when really it should be a 40.
        
         | KennyBlanken wrote:
         | That study is nearly ten years old and almost certainly not
         | relevant anymore.
         | 
         | The Basis Peak did a good job at tracking sleep but they got
         | bought up and killed off by Intel for god knows what reason.
         | The Peak also did automatic activity detection and it was quite
         | good at it.
         | 
         | Basis also had hands-down the best visualization of activity
         | and sleep trends, and was the only watch at the time to do full
         | time HRM.
         | 
         | They claimed the Peak watches were a fire risk and recalled
         | them, probably to have a reason to get rid of all the back end
         | infrastructure.
         | 
         | Garmin still can't reliably autodetect biking and its sleep
         | tracking is pretty terrible, too.
        
         | jeremiemyhren wrote:
         | I miss the Zeo. The app would still work locally long after
         | they shut the backend down, until there just was no more
         | aftermarket / eBay supply of their unique silver coated contact
         | padded headbands that actually did the brainwave monitoring. I
         | do find the Apple Watch Ultra seems to be close to at least
         | being in the ballpark in terms of stage and duration accuracy
         | as its output is comparable to what I last got with Zeo, albeit
         | 10 years ago.
        
         | verticalscaler wrote:
         | This review channel begs to differ:
         | https://www.youtube.com/@TheQuantifiedScientist/videos
         | 
         | He very throughly compares countless models with a Polar H10
         | strap. Some come close enough.
        
         | CharlesW wrote:
         | > _Wrist watches can 't really detect sleep stages._
         | 
         | As someone else noted, the paper you linked to is from 2015.
         | Apple Watch couldn't do it until watchOS 9 (2022, 7 years
         | later), but can now do this pretty reliably.
         | 
         | You might find the "Algorithm Development and Validation"
         | section of this whitepaper interesting:
         | https://www.apple.com/healthcare/docs/site/Estimating_Sleep_...
        
           | pkoird wrote:
           | Thanks for linking this. I always did wonder how they did it.
           | From a cursory read, it looks like the basic approach is to
           | collect accelerometer data and train it to predict ground
           | truth labels generated via a consumer EEG device. Not sure if
           | each epochs (30s) were considered iids. I'd assume that the
           | overall sequence of activity would be much more informative
           | than a single 30s activity considered independently.
        
             | cj wrote:
             | Sometimes at work I'm concentrating so hard my Apple Watch
             | logs a sleep session...
             | 
             | Definitely not 100% accurate but as someone who checks
             | their sleep log (and time in each stage using the Pillow
             | app) daily, it seems pretty accurate and I can correlate
             | how I feel on a given day back to that day's sleep report
             | with pretty good correlation.
             | 
             | Definitely not perfect but better than nothing.
             | 
             | If you've ever been on medication that suppresses REM
             | sleep, Apple Watch detects REM rebound very clearly.
        
         | pedalpete wrote:
         | The data quality of wearables to detect sleep stages is in the
         | 90%+ accuracy range now. Which is near what polysomnographers
         | score at - nobody completely agrees on what stage is what,
         | there is always deviation. Wearables are definitely good enough
         | at this stage.
         | 
         | Zeo is not the only consumer EEG either, though all the current
         | headbands (including what we are building at
         | https://affectablesleep.com) have some sort of sleep
         | stimulation at it's core.
         | 
         | Frenzband I believe is shipping, I haven't tried one, and don't
         | know anyone who has. We have a Somnee at the office, and it is
         | unbearably painful to wear. I'm highly skeptical of the
         | "science" of either of these devices as well.
        
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