Amazfit (Zepp) Smartwatch - Sleep tracking experiment

in #smartwatchlast year (edited)

@sulayr and I have worn the Amazfit Smartwatch for the past 4 months or so, and last night decided to see how our sleep was tracked when we swapped devices.


I've really enjoyed tracking my daily activities, my active and resting heart rate, and trying to lower my fitness age down to early 20's using the watch over the past couple of months, but one metric we both like to compare daily is our sleep quality according to our devices.

I've long thought that I am a light sleeper and my sleep quality to be on the lower side of average, but after wearing the watch over the past four months this perception has changed as my sleep has averaged at around 7 hours in total with about 2.5 of those hours in a deep sleep. According to the watch, this average puts my deep sleep in the top 10% of those wearing the Amazfit brand.

@sulayr, on the other hand (hmmmm), sleeps a little longer than me on average but rarely obtains even an hour of deep sleep each night according to her Amazfit - although rarely remembers waking up during the night. I often wake up for the toilet at least once, and regularly have a 'rest' from sleeping after 3/4 hours in bed. And because of the deep sleep totals, my sleep quality is almost always scored higher than hers.

Swapping... devices

The first image below shows our sleep analysis for the night of the 12th / morning of the 13th September 2020. My record is on the left and despite waking up twice and sleeping for less time in total, I obtained almost two hours more deep sleep and achieved 8 more points on my sleep score.


The image below is our record for the 13th/14th September. Less than two hours deep sleep for me this time, but only 25 minutes of deep sleep recorded for @sulayr - not much at all for someone who rarely wakes for the toilet and feels mostly refreshed each morning.


It's probably worth mentioning that the sleep detection of Amazfit is mainly based on "body movement" + "heart rate". When the body movement is small and the heart rate is low during sleep, it is considered as deep sleep.

Looking back through our records, we can see a similar pattern and scores. I generally get less sleep in total but record a couple more hours of deep sleep.

So, what happened last night (14th-15th September) when we swapped our watches?

Again, my application data is on the left, but it was @sulayr wearing my device. Her app's results are on the right, with me wearing the watch.


With my watch, @sulayr earned 2h 39m of deep sleep, just two minutes less than my result on the 13th. With @sulayr's watch, I collected 25m of deep sleep, exactly the same score as she got wearing her own watch the night before.

Although not a thorough experiment, as only one night's data with each others watch was recorded, it seems like it doesn't matter who wears which watch - mine records far more deep sleep. 25m is my worst deep sleep score by over an hour and a half, and 2h 39m is over 1.5 hours better than @sulayr has ever scored with her watch.

So who's watch is closer to the truth? Mine, hers, neither? I'm a bit disappointed to be honest, even though "body movement" + "heart rate" doesn't sound like reliable indicators to begin with.

Next stop, Garmin?


This comment was made on one of @tarazkp's posts when he wrote about his Amazfit which breaking soon after purchase in June. Although mine hasn't given me any major problems, I do think I'll be heading for a Garmin at some point soon. The watch has quickly become a key motivational gadget for me, and I want what it tells me to be accurate!

Well, worth a shot I guess?.... :)





Im not impressed with mine either. But it's a good starter watch. I guess cause I probably wouldn't have shelled out 300$ for a good watch, but now I will. Maybe after a year, I'll get a new one because I hate wasting money.

Besides, sleep tracking isn't that valuable.

I am also disappointed with zepp. I still can't pair it with my scale that does body fat and such. I can't even enter in that stuff manually. It's such a tease, lol.

I remember you saying you thought sweat was buggering up the heart-rate - mine has been pretty good in that department (as far as not losing track) since I tightened the strap up.

The Zepp app seems to have lost 2 months of my resting heart rate data, and looking on recent forum posts it seems a bunch of people are reporting other strange events.

So yeah, an upgrade at some point I guess - hopefully a freebie from Garmin :D

Yeah I had another problem witb the heart rate yesterday. I usually tighten it up before an exercise, but like to wear it loose during the day.
I'm not too concerned about 24hr tracking.
Also I don't really jog, so built in GOS isn't a huge must for me as I can just pair it to my phone when cycling. The heart rate monitor is important.

I hope you get your garmin. I'm looking into those and Samsungs because my next phone will probably be Samsung and living in Korea my privacy concerns are nonexistent because privacy is a foreign concept.

I have been adjusting for workouts too - the print left following workout tells me it's too tight for general wear.

Not really sure where to go next - Apple is an option but I hear Tesla are in the game too...

I've had a real live honest to goodness sleep study done in a lab. I got less than 10 minutes of rem sleep in the 8hrs I was in bed. Not so good.

7 electrodes on my skull and an O2 sensor on my finger. Because of the results I had to stay the day for a 'sleep latency' test and averaged under 2 minutes per nap cycle throughout the day. That is somewhere near the bottom on both tests.

Jeez! That sounds terrible!

Were there any reasons given as to why? And, how do you cope?!

Yes. It was to verify the diagnosis of Narcolepsy and moderate sleep apnea. Not a particularly good combination. I have been surgically corrected to a non troubling level of apnea. The Narcolepsy goes on.

Ahh. A double whammy that sounds rather mission critical. Glad that one aspect has been improved, and I wish you well in finding out how to improve on the narcolepsy.

I'm about 25 years in, I'd guess I'm used to it :)

Damn. And you still seem to have your marbles!

It's miles ahead of my android watch. Although I believe there is a big fitness update coming. I should download it but since lockdown I have hardly worn it

It's been the opposite for me, more exercise than ever!

Perhaps a nice update will get you moving?!

It might do. My knee is healed now from whatever strange knock it had. I am raring to go!

Sounds like it's tracking your 'profile settings' not your sleep. What a heap of shit!

Ahh, yep, if that is the case - bag of shite!

It's something worth investigating further - if it really is the case then surely there's a huge legal claim to be made against the company? Unless it's all covered in the small print, probably is.

small print:

this watch is shit.

😂 110 notes at well, balls.

Well hopefully Garmin have replied to my tweet and are winging a freebie for me to advertise their outstanding product............

hhahahah! that was my comment yes...
These data are only approximations obtained and related through your Heart frequency sensor but, as far as I know, these heart frequency sensors based on "light variation" are not accurate enough. Any movement can affect the acquisition of the data...A heart-frequency belt/band used to be more accurate on this measure.

Right. Any idea why my readings with her watch look exactly like she's wearing the watch, and vice-versa?

It looks like, as revisesociology suggests, that they've basically taken an average over the past weeks/months and gone with that.

Yep, it makes sense

Thats quite the watch. I love gadget watches. Its actually wuite sleek and cool looking too. The sleep analysis is interesting. Its provides a lot of details. I don't think that the sleep function on my fitbit blaze could do all that.

Yeah I'm a big fan, and am looking forward to seeing what's available as tech advances.

You’ll end up with an Apple Watch eventually.

Boo hiss! :0P

Currently using an Android as main phone. :P


I'm generally platform agnostic and occasionally need a change, as well as explore what the other side is doing.

I do have principles about privacy tho and all "phoning home" my Droid does is quite annoying. While my Google accounts are configured to store as little as possible data, there's still a lot of traffic happening which could totally be done on device or doesn't need to happen. In that aspect I definitely side with Apple's attitude to privacy.

Last time I switched back to iPhone I was like "WTF, the simplicity is awesome. Why did I enjoy all those extra settings on my droid again???"

But I truly want Google to step up and build a solid alternative for tablets. The iPad Pro has almost completely replaced my MBP (by choice, it allows me to focus better than I do when on laptop with a configuration for speed and multitasking). And I want a LINEAGE OS build for my phone so it stops calling home and making me the product. :P

Agnostic is the best way to be. Myself and some of my friends are always talking about what is best regardless of platform loyalty.

You are damn right on the tablet. I think a lot of it comes from app makers designing specifically for tablets. Maybe they need a push from Google to produce certain apps for certain niches. Look at garage band? Everymusician I know wants an iPad so that they can use garage band. The android choices are woeful.

You could always carry your phone about in a lead case? :OD

Apps happen because of APIs. It's true both products are totally different: Apple is a selective hardware platform, Android must operate with a crap load of shit hardware configs as well.

When it comes to music iOS is in an entirely different league, probably universe even. It continues Macintosh's legacy of connectivity too. It's not just GarageBand, it's that apps can be written for devices to be connected to iOS. And yeah still waiting for Gorillaz to release an album "Made on Android".

Wearing my phone in a case doesn't change how the platform manager handles my data. Unless you meant a case McAfee would use to be disconnected, I just take out the battery if that's my aim. :P


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I do have an iPhone but was thinking about going elsewhere when it dies. Do you have the Apple Watch?

No, I don't. For one I don't like rectangular watches and I also like my watch to do one thing and only one thing: indicate time. I actually love time pieces and when crypto moons...

I've been through Pavlov's dog experience with the original Pebble and while I do have a Mi Band, configured to notify me of almost nothing, I have no idea in which drawer it is currently.

I do admit an ongoing interest in the devices though, but not as health trackers yet as health prevention devices.

I'm looking forward to seeing what is done with these watches in the future. Checking for vitamin/mineral levels would be cool.

We’re still waiting for Tim Cook’s Apple Watch. On campus he wears a prototype which monitors his sugar levels (he’s diabetic). He has several times mentioned that in fireside chats/interviews. There’s also a FDA and FTC license for Apple but the monitor is not detailed, which means they probably think they’ve found the right size but not yet how to fit it in the Watch optimized for mass production.

But yeah it’s a hugely promising niche and with processors now being made at 5nm we can expect neural learning in watches soon as well.

I would only trust all that data to a company with an actual pro-privacy position like Apple though. Google has long time ago damaged any privacy trust I may have had.

Ahh, there are watches available with certain health tracking already - I guess it won't be long then, especially with tech moving so fast.


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Perhaps it is like my English teacher in high school - the grade for the first assignment became the grade for all assignments... :D

Yep, seems that way, pretty poor to be honest. How's your watch doing? Care to share your sleep/resting heart rate?

Now of course, to prove it does actually measure the sleep of the person wearing it, you should commit to this experiment for 6 months 😅.

So.. according to the product description, how does the watch actually measure your sleep activity? Heartrate?

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Certainly more than a day 😁

But those readings after swapping are around the 4month average when we wear our own watch - suspicious!

Heart rate and movement combined - I think it should be listening too, but many people don’t like that idea.

Really suspicious indeed 😅

As for the listening... uhm.. no thank you. I'm one of those people that would not like my watch listening to me sleep 😂😂😂.

Bummer. It's good that no matter what this watch shows, you'll not lose sleep over it hahaha, ironic

Not really no :(

I'm not sure which watch to believe - neither I think!

Hahaha I can imagine. I'd just let the sleep be sleep, no more tracking😂

Nice experiment. If you are interested in ways to improve/moderate deep sleep, look into polyphasic sleep. It's said that people who train their body to achieve a polyphasic sleep pattern can reach the deep sleep phase much faster, which is the most important part for daily recovery.