
How Much Sleep Do Fitbit Users Really Get? - OrwellianChild
https://blog.fitbit.com/sleep-study/
======
SimonPStevens
I'd take all of this with a giant pinch of salt. If the data is anything like
the sleep data generated by my Garmin vivosmart HR+ it's not much better than
garbage.

It frequently counts me as sleeping when I sit down to watch TV in the
evening, or read a book in bed. Sometimes I stay up until 1am reading and it
always tracks me as deep sleep from 10pm when I got into bed. I usually take
it off for my morning shower (It is waterproof, it just annoys me when
washing) and it nearly always counts the walking from bed to shower as a few
minutes of restless sleep and the shower itself as deep sleep.

I'm not sure how it makes an assesment of my sleep level. I don't know if it's
just based on movement or if it takes heart rate data into account but it does
have a heart rate sensor. It seems to usually be wrong.

In theroy it would be possible to know about these limitations and adjust your
use of it to make it more accurate, but unless the participents of the study
are aware of that and have been manually correcting the data then that won't
be the case.

(Not a general critisim on the device, I like it for everything else, but it's
sleep data is clearly rather inaccurate)

~~~
OrwellianChild
These are all worthy considerations for these trackers... I can only speak for
the Fitbits, specifically the Charge 2 (which has a HR monitor too).

Fitbits have 2 measurement modes for sleep - normal and sensitive. Normal
pretty much tracks me as sleeping like the dead for 8 hours each night
(however long I'm immobile in bed). Sensitive, on the other hand, tracks much
more detail and can tell when I'm restless, sleeping deeply, and even when I
get up in the night and move around. _I highly recommend the sensitive sleep
setting for Fitbit users - it gives you more data to play with!_

Fitbit recently re-worked the way they track sleep in its HR-monitor-equipped
devices (Charge 2, Aria HR, etc.). It introduced more details (it was just
tracking restless/deep before) and this upgrade greatly improved the sleep
tracking for me. Before Sleep Stages, it would track only 3-4 hours of my
sleep each night. Now, it catches the full 6-9 hours.

Now, all of this is to be taken with a grain of salt in terms of accuracy, but
to compare _among Fitbit users_ and _to yourself over time_ , this information
is incredibly useful!

The strongest example of the usefulness of this for me so far has been the
effect of moderate alcohol consumption on the quality of my sleep. I am far
more restless and get much poorer sleep after drinking just 1-2 beers on a
full stomach. This has led me to cut back almost completely on alcohol and the
quality of my rest has dramatically improved!

~~~
iClaudiusX
How do you know if it's "catching" anything other than noise? Have you done
any kind of comparison against a gold standard method like a sleep study?

From what I can tell, none of these accelerometer-based methods work at all
and the companies pushing these as sleep trackers are making false claims.

~~~
OrwellianChild
Like I said, accuracy isn't so much the goal... The readouts I get show pretty
_consistent_ measurements over time, which gives me enough confidence to
compare them to other Fitbit users among my friends/family as well as to
myself over time (see the alcohol anecdote above).

Setting the sensitivity to "normal" just raises the noise floor in their
filter so high that it obscures the data.On sensitive, I've never had issues
with it identifying "sitting" as "sleeping", yet it still effectively tracks
my sleep (including periods of wakefulness immediately pre- and post- slumber
in bed as well as mid-night disruptions that wake me up). This suggests that
I'm getting pretty good data (though not equivalent to a sleep study with
ECG/EKG equipment). In this case, "good" is good enough for my uses.

------
johnchristopher
FWIW I have been using a flex 2 for two weeks now and I couldn 't believe how
I messed up my sleep. I was a trainwreck and going for no more than 5 hours
per night while misevaluating my sleep time to 7-8h. I decided to break the
cycle and I have been sleeping much more for one week and already can see the
difference. I think I should have bought an alta or a charge to get the
benefits of the HR monitor. Still, I am glad I bought one. It was a reality
check. And I bought it because I really wanted an vibrating wrist alarm.

~~~
Swizec
Similar story here. I always thought I slept like the dead and nothing short
of a force of nature could wake me.

Fitbit rolled out their new sleep types tracking and I find out I'm actually a
super light sleeper. Most nights I don't get anywhere near the low-end
benchmark for Deep Sleep and I overshoot the high-end benchmark for Light
Sleep by many points.

It's weird because my subjective experience and the data that Fitbit shows are
so out of whack. I could swear that I sleep well, but nope.

~~~
just4themoney
I hate to be so pessimistic but since Fitbit doesn't measure brain waves
(among many other things) any "sleep" data generated by the Fitbit is
somewhere between those novelty love tester machines and random bits in
accuracy. Don't trust it over your subjective experience.

------
Sir_Substance
I know that fitbit thinks this is really cool, but this is really creepy.

Everyone who owns a fitbit has doubtless signed off on being part of these
kinds of studies if you dig all the way into fitbits EULA, but I bet none of
them actually got an email saying "click here to opt in/out". For a lot of
fitbit users, they will never see this study and it will never cross their
mind that they're being studied.

This is why I searched high and low for a fitness tracker that doesn't have an
online component. I eventually settled on a garman fitness watch plugged into
turtle sport:
[http://turtlesport.sourceforge.net/EN/home.html](http://turtlesport.sourceforge.net/EN/home.html)

~~~
throwanem
I don't really worry about this kind of data being in The Cloud(tm). All the
GPS integration is disabled, and I've explicitly forbidden the app any access
to location services, so it's not tattling to the world about _where_ I am,
and the level of exertion I'm hitting at the present moment, or the extent of
time during which I'm asleep, isn't something in which I see any significant
potential for exploitation.

------
Skunkleton
These types of articles often have a correlation vs causation problem. For
example, the article says that if you want better deep sleep, then move your
bed time to between 9 and 10 PM. Ok, sure the data shows that people who go to
bed at this time have more deep sleep, but why? Maybe it is a longer window to
sleep in without light/noise? Maybe people with fewer sleep problems go to bed
earlier? Is it because going to bed at 9:30 is magic?

What am I supposed to take away from this?

~~~
posterboy
> Is it because going to bed at 9:30 is magic?

I guess, the inner clock is adjusted to that time because that's when the sun
goes down in summer, and when melanin increases, because of changing light
levels, we become sleepy.

just , a shot in the dark so to speak ;)

------
wimagguc
It's interesting insight into how much sleep people actually get, but the
article mixes up actual statistics with some random data pulled from
elsewhere. What's missing is, for example, the data on how the amount of deep
sleep impacts the individual's short-term memory, activity and "feeling
refreshed" (sic).

We don't actually know where those stats come from, so this conclusion is a
bit far-fetched: "these findings further support the general recommendation
that most adults need to consistently sleep 7 to 9 hours per night".

------
tejaswiy
Since noone's asked this question yet, how accurate is using movement / heart-
rate as a proxy for EEG when estimating sleep patterns?

~~~
ared38
Mine didn't have HR monitoring, but I found the movement (aka actigraphy) to
be pretty much useless. Fitbit was counting all the time I was laying still
trying to fall asleep as "deep sleep", and looking at the chart I couldn't
differentiate movement at 12:00 when I knew I was awake from movement at 6:00
when a noise woke me up but I fell right back asleep.

The movement data is probably enough to tell when I've slept better or worse,
but I wouldn't trust the absolute "number of hours of sleep" they report.

~~~
brlewis
Fitbit does not attempt to track sleep stages w/o HR monitoring; it's just
Awake, Restless or Asleep. Yes with nothing but accelerometer data stillness
can be mistaken for Asleep, but I think you're misremembering when you say
"deep sleep".

------
pcunite
I try to run or bike several times per week. Will be adding tennis soon if I
can. What seems to affect my sleep is occasional restless leg. I have to get
up and do stretches or use something like the TigerTail to be able to stop the
nerves from firing off. I'll toss and turn if I don't address it.

~~~
mantas
I've similar issues once in a while. Taking a month's course of magnesium
usually helps. Your reasons and results may vary though, I'm not a doctor.

------
cmiles74
I was doubting the effectiveness of my CPAP machine and decided to take the
night off. I usually sleep close to eight hours with 3 to 4 hours of deep
sleep; without the machine I sleep about the same time but log only 30 minutes
to an hour of deep sleep.

~~~
Mahn
> _I usually sleep close to eight hours with 3 to 4 hours of deep sleep_

Sounds like you are getting better sleep than most healthy people. I always
wondered if one could benefit from a CPAP machine even without suffering from
sleep apnea.

~~~
cmiles74
My partner sleeps poorly and I have wondered the same.

You are right, I should be grateful for the machine. But the mask is a hassle
and I find myself getting cranky about it. Still, I wear it every night. It
was definitely reassuring to see what a difference it makes.

I should try and talk my partner into trying it. ;-)

------
Anand_S
Data from Fitbit can help you see patterns which otherwise you won't notice. I
used to stay near a Railway Station, and my sleep used to get disturbed every
30 mins. I did not realize this until I saw the data from Sleep tracking. I
was getting less than 50 mins of deep sleep and I could easily see that the
deep sleep was disturbed at exactly the train timings daily. With this
knowledge, I moved to a new place with less disturbance during night. Now my
Deep Sleep is increased by 50% after this move.

------
OrwellianChild
I am almost exactly typical in hours of sleep and mix of sleep type to the
aggregate. What's hidden is all the volatility in my sleep... In my last week,
there is a range from 5.5 to 8.3 hours of sleep in a given night. The longest
sleep nights don't necessarily follow the short sleep nights either, so it
doesn't appear to be catch-up sleep. Weird body is weird.

Other interesting notes:

1\. Women need an extra half hour?

2\. People sleep less as they age?

3\. "Generation Z" is what we're calling kids these days?

~~~
pcunite
_2\. People sleep less as they age?_

In my experience a lot of older people seem to say this. Note sure why it's
true.

~~~
swift
In the case of my own family members, this seems to stem from physical
maladies that are correlated with age - back injuries, for example, or weight
increases aggravating sleep apnea. I'm not sure how things look for old people
who are extremely healthy, though.

~~~
Someone
[http://www.sciencedirect.com/science/article/pii/00319384879...](http://www.sciencedirect.com/science/article/pii/0031938487903210):

 _" The mean sleep duration (from PAM) equaled 7.29±0.8 (S.D.) hr compared to
7.84±0.62 hr as estimated from the daily diaries. Neither parameter was
correlated significantly with age (p>0.05)"_

(N=43, 9 days, age range 21-83)

------
notheguyouthink
According to my Fitbit _(which I wear constantly)_, I get on average ~3h45m of
"sleep". It apparently doesn't count restless as valid sleep, so it heavily
eats into my sleep. Most of the ~8h chunk I'm asleep it marks as restless..
probably not a good sign lol.

Though, I don't think I'm using their new sleep phase metrics, as my Fitbit
app doesn't seem to have it.

~~~
colonelxc
For me, the fitbit overestimates my sleep by a wide margin (and I stopped
using it for that purpose). It assumes if I am not moving that I am asleep.

~~~
waivej
I had to switch it to sensitive mode for the same reason. It's also more
useful as a relative metric than specific number.

------
sjclemmy
> People who sleep 5 hours or less a night deprive their body of the
> opportunity to get enough deep sleep, which occurs near the beginning of the
> night.

I'd like that explained to me. If it's something that happens near the
beginning of the night how does duration affect it?

------
petepete
At least it has chance to measure sleep. My Android Wear device (Huawei watch
V1) has no battery by evening and has to spend the night charging.

------
punjabisingh
The sleep tracking from my FitBit is my favorite feature. Even the cheapest
FitBit Flex provides good analysis of my sleep (restless, awake, duration,
etc). I use it more to make sure I get 7-8 hours to sleep than to count steps.

Disclosure: volunteer beta tester

------
huangc10
It'll be really interesting to see the sleep data compared against other
countries or continents. Sex and age is interesting but you can't tell much
from this data. Could comparing it with other countries correlate with a
country's economy, culture, general state of affairs? Also, if there is a year
to year trend cross reference with country.

If this data is accurate, it could be useful in determining a country's future
economics. Ie. perhaps a general population's 5 mins of average less sleep
means more stress which means more economic downturn/changes?

------
ComputerGuru
The only accurate sleep detection I've had from all the devices I've tried is,
surprisingly, my $20 MiBand (both the original and the MiBand 2). I don't
think it's a hardware issue, I'm pretty sure it's just stupid software.

The results I've gotten from the SleepCycle iPhone app - all the way back in
2009 - are more precise than any of those other fitness trackers. It used to
rely on the uber-sensitive iPhone accelerometer but they "recently" switched
to using the microphone for some reason.

------
Kluny
Average is such a useless measure, what if there is a bi- or tr-modal
distribution, or a huge number of outliers in one direction or the other? I
wish they would include modes and medians.

------
jkimkidding
I've tried sleeping with my Fitbit Charge HR 1 but often found that it
hindered my sleep. The green light that monitors activity would show ever so
slightly and ruin my sleepiness.

~~~
appleiigs
Fitbit Charge 2: if you move your arm while trying to fall asleep, the display
lights up right in my face. Apple's cinema mode for the watch sounds good.

~~~
latkin
This bothered me, as well. If you disable "quick view" then the display only
lights up when you tap it. That's a big improvement, IMO, though if my hands
are full it's harder to check the time.

~~~
zimpenfish
Disabling "quick view" also saves a chunk of battery life. Which is always
helpful.

------
peterjlee
TIL Gen Z is a thing. I feel old. Also, I'm guessing most Gen Z fitbit users
are in college because there's no way high school kids can wake up at 8:12AM
and go to school.

~~~
rb808
Interestingly what is the next generation after Z - are we back to A again?

~~~
kylec
AA probably. That's the column to the right of Z in Excel.

~~~
ghostly_s
Nothing post-gen-Z'ers relate with more than Excel.

------
uses
This info would look really nice as stacked bar charts. And the average sleep
/ wake times would look great as parallel timelines to show start / end times
of sleep.

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beeeebo
Looks like my pattern I wear a mii band it was 20 bucks baby

------
zurn
Is there a monitor like this that won't send your data to the cloud?

~~~
kqr
Well.... any device not connected to the internet will plainly not send your
data to the cloud. Then it's the matter of parsing the data on your own, which
at least for Garmin devices should be possible once you figure out the format.
(If someone hasn't already, was a while since I explored that.)

~~~
zimpenfish
The FIT file format is available online (might have to sign up to the ANT
Consortium or something, I forget.)

But...it was designed and implemented by embedded engineers who looked at TIFF
and thought it wasn't batshit enough.

[http://garmin.kiesewetter.nl/](http://garmin.kiesewetter.nl/) is useful for
converting them to CSV and extracting the data that way.

------
neves
Does it track snoring?

~~~
zimpenfish
I don't think any Fitbit has that functionality yet. SleepCycle for iOS has
"snore detection" if you use the microphone mode (I suspect other apps have
similar options by now.)

------
ram_rar
Unless there is some kind of sensor in the pillow, which can calibrate your
sleep. None of these fitness trackers can accurately measure your sleep.

~~~
eduren
What makes a "pillow sensor" more accurate? Is there anything like that on the
market?

~~~
ram_rar
Sony has patented in this area. [https://www.engadget.com/2013/02/08/sony-
patent-application-...](https://www.engadget.com/2013/02/08/sony-patent-
application-puts-electrodes-in-a-pillow/)

~~~
eduren
You're honestly comparing the accuracy of a product out in the market, with
one in the patent stages back in 2013?

I understand being skeptical of the accelerometer + hr monitor solution, there
are certainly more involved ways of analyzing patterns that are available to
sleep specialists. But how does it help the discussion to dismiss it in favor
of a non-existent product?

~~~
ram_rar
My point is, a sensor in the pillow might be more accurate in tracking your
sleep than a fitness tracker. Thats all!

------
sgt101
Average? Mean or Median!

------
racl101
I have a Fitbit and love to use it for step counting but I sure as heck don't
sleep with that thing.

------
blunte
Well, those of us with the top of the line model, the Surge, can't really
contribute to this discussion. Why can't we contribute? Because Fitbit has,
for whatever reason, chosen not to include its highest paying customers with
the same features they've given to their lesser models.

[https://community.fitbit.com/t5/Feature-Suggestions/Sleep-
St...](https://community.fitbit.com/t5/Feature-Suggestions/Sleep-Stages-for-
Surge/idi-p/1908806#comments)

~~~
throwanem
That's a shame! Perhaps a model closer to the middle of the range will suit
you better.

