Apple Watch Series SE: A Fitness First Impressions Untangled


At first glance, the Apple Watch SE seems like a straightforward Apple Release with SE branding: Take a roughly year-old model, cheapen out some materials, and call it the SE. But in reality, it’s far more complex than that, and puts together what Engadget accurately called the Frankenwatch. And unfortunately, as I discovered, that’s most visible in the sports and fitness realm.

Now, I’ve been using this device for a few days worth of workouts and I figured I’d dive into some of that initial workout data, primarily from an accuracy standpoint. This isn’t a full review, but rather a look at what’s different about the SE and where it slots in to the Apple lineup, all from a fitness standpoint. I’m not going to go into the nuances of the processor (because frankly, you’ll never notice), nor Apple watchOS7 (since I did that here). From a software standpoint, all three watches are identical, and all features unless hardware-dependent are identical.

Now if you want to jump right into it, here’s a video I put together diving through all these tweaks. Plus, a bit of a tour of my running route in Amsterdam.

And again, I’ll likely dive into a full review down the road. But for now, my initial thoughts.

What’s Different:


Thus, to begin, let’s set the stage for what Apple has slated as their lineup for the next year:

Budget: Apple Watch Series 3 – from $169 (officially from $199, but it’s already been at $169 for months)
Mid-range: This new Apple Watch SE – from $279
High-end: The new Apple Watch Series 6 – from $399

And then there’s the cellular variants of all these as well. But that doesn’t really change the fitness paradigm, so we’ll ignore that. All of these have GPS, all of them have two size options, and all of them support the latest watchOS7 operating system that just released last week. But that’s kinda where it seems to end from a fitness standpoint. The Series 3, SE, and Series 6 all use different optical HR sensor designs, and all have differences when it comes to battery life for GPS workouts. The functional level of their heart rate sensors is notably different too, as you’ll see in my tests.

From the front, the three units look near identical. Of course, the Series 3 has a smaller display within that shell, but beyond that, between the SE and Series 6 they’re basically indistinguishable from a glance.


But when we flip it over to the back of the three watches side by side, you can see the optical sensor layouts are all different. At left, Series 3, then SE, then Series 6.


What’s funny here, is that Apple’s own page on this is incorrect, where it states the SE has a second 2nd gen optical HR sensors:


Except, that’s quite clearly incorrect. This claim is repeated numerous places on the site in numerous articles. Here’s the full sensor arrangements of all Apple Watches. Also, I know it’s tough to see with reflections. There’s no ‘good’ angle to take a picture of multiple Apple Watch sensors due to the highly reflective nature of them and that they have a slight crown to them.


(Left to right: Original/Series 2/Series 3/Series 4/Series 5/SE/Series 6)

They’ve actually had three optical HR sensor generations:

Apple Watch 1/2/3: This is a 2xLED, and 2xPhotodiode arrangement
Apple Watch 4/5/SE: This is a center LED (which technically has 4xLED’s in it), 8xPhotodiode arrangement
Apple Watch 6: This is a 4x LED (with each LED also having two colors in it, green for HR, red for SpO2), 4xPhotodiode

Anyone can simply look at the back of an Apple Watch and see these are different. This isn’t some secret here. And in fact, in the keynote for the Series 4 they touted the new optical HR sensor, just like they touched on its increased capabilities in the Series 6 keynote.

I asked Apple why they claim otherwise on their site. I’ll circle back when I hear why.

In any case, that of course has impacts on accuracy. In most cases it’ll be negligible, but if there wasn’t changes to accuracy (or power draw), then Apple wouldn’t have made changes. Companies generally change these things to eke out that last 1-2% in accuracy increases. It’s a slow and iterative process.

Practically speaking though, this manifests itself more simply in terms of features as:

Apple Watch 1/2/3/SE: Heart rate measurement
Apple Watch 4/5: Heart rate measurement + ECG
Apple Watch 6: Heart rate measurement + ECG + SpO2

And then more fully if we look at the core features people care about related to fitness, the following:

Apple Watch Fitness Comparison

FeatureApple Watch Series 3Apple Watch Series 4Apple Watch Series 5Apple Watch SEApple Watch Series 6
DisplayRaise to wakeRaise to wakeAlways onRaise to wakeAlways on
Battery Standby18 hours18 hours18 hours18 hours18 hours
Battery GPS Workout5 Hours GPS6 Hours GPS6 Hours GPS6 Hours GPS7 Hours GPS
Fast charging1.5hr to 80%1.5hr to 80%1.5hr to 80%1.5hr to 80%1hr to 80%
Optical HR SensorGen 1 (AWS1-3)Gen 2 (AW4/5/SE)Gen 2 (AW4/5/SE)Gen 2 (AW4/5/SE)Gen 3 (AW6)
Heart Rate NotificationsYesYesYesYesYes
Display Brightness1000 nits1000 nits1000 nits1000 nits1000 nits
Water Resistance50m50m50m50m50m
AltimeterYesYesYesYes PlusYes Plus
ProcessorS3 SiP ChipsetS4 SiP ChipsetS5 SiP ChipsetS5 SiP ChipsetS6 Chipset
Storage (music/apps)8GB16GB32GB32GB32GB

There’s also some other nuanced things like the Series 6 includes 5Ghz WiFi support, the U1 broadband chip, and both the SE/6 include the W3 Apple Wireless chip versus the W2 on the Series 3.

In terms of sleep data, the SE acts just like all the other watches. You’ll set up sleep tracking through the 98-step sleep tracking wizard, at the end of which the watch will track sleep as long as a sleep schedule is enabled. You can then see the sleep data the following morning on your watch or on the app. Here’s the data from last night, tracked on the SE:


The start/end times are mostly correct, as are the brief moments awake. Here’s the slightly more detailed data from the Apple Health app:

AWSE-Sleep1 AWSE-Sleep2

Ok, with that – let’s get on with the run.

Test Run Data:

I detail much of the accuracy bits in the video, but I figured I’d quickly go through the main aspects. I had multiple devices with me, including the Apple Watch SE, the Fitbit Sense, the Garmin FR745, a chest strap (Garmin HRM-PRO), the Polar OH1 Plus, and the Whoop strap, all properly spaced and not-conflicting with each other. Albeit, it didn’t help that I apparently forgot to start the Polar OH1. And then the Whoop strap didn’t properly sync to Strava (the easiest way to export the data). Still, I could look at the core elements on Whoop’s site and manually compare where required.

Starting with the heart rate. This run was mostly evenly paced, but I threw in some solid sprints to check out responsiveness, and unfortunately, the SE failed on one of them – spiking the heart rate considerably higher than my viable max HR (and certainly higher than my effort) – nearly 190BPM:


Even the Whoop strap got this sprint correct – topping out at 177 like the chest strap:


I mean, c’mon, when’s the last time from an accuracy standpoint the Whoop strap beat anyone? You know you’re up crap-creek when that happens.

In any case, the rest of the workout was actually fine heart-rate wise.

It’s GPS that’s where the problems are. And in some ways, it’s easiest to just show Apple’s own app here, because it so easily makes things clear. With the Apple Watch Series 6, gone was what I’d dubbed ‘Mario Karting’ (or ‘Whooshing’) around the corners, where basically it ignores the laws of physics for GPS track beauty. It’d cut many corners, even when water/bridges/buildings/trees/rocks/statutes/angry geese, and others were involved. It’s been a stable of Apple Watch GPS tracks since the beginning, but the Series 6 unquestionably got rid of it. The SE though? Oh, it’s still here in force. For example, these on this run and my run from Sunday too:


But, to show how other watches handled these points, we go to the data. For example, look below at how it both ignored the bridge on the left, and then ignored the turn of the tip of the island.


Or the loop around the stadium, where it was mostly in the bleachers, and the Garmin was correctly on the road where I ran:


On the running track, the Apple Watch undercut each loop, being inside on the field. The Garmin wasn’t in the new Track Mode, but still got on the track properly. Also, when exiting the track, the Apple Watch cut everything (I actually show a live side by side of this in my video with footage of it ignoring it).


In the woods it was mostly OK, though it did still short almost every corner. The one exception being one corner in the lower left, in which case the Garmin very slightly undercut that one:


The challenge here (which it was before), isn’t that it’s always short or always long. It’s that it’s inconsistent with what it does. Sometimes it overshoots when it smooths because it goes wide coming out of a corner (like Mario Kart), and sometimes it undershoots because it cuts corners. Thus the distance in the end might be similar, but it also very much might not be.

I guess after testing the Series 6, I had hoped 2020 would have been a turning point for Apple and GPS accuracy. Either via hardware updates in the Series 6 & SE, or via software updates in watchOS7. Unfortunately, whatever magic is in the Series 6 simply isn’t in the SE.

(Note: All of the charts in these accuracy portions were created using the DCR Analyzer tool.  It allows you to compare power meters/trainers, heart rate, cadence, speed/pace, GPS tracks and plenty more. You can use it as well for your own gadget comparisons, more details here.)



So, I guess I’m ultimately left a little bit confused at this point. Undoubtedly the Apple Watch SE will sell well, because…Apple. But I’m here at this point thinking that the real purpose of the SE is to actually drive Series 6 sales. Or, perhaps solidify Series 3 sales from people on the fence of Apple at all. Sure, there will be a handful of people that get the SE over a Series 3 because it has more storage (or a larger screen), or is marketed as faster. But in general, it feels a bit like a watch designed to underperform. And I very rarely say such a thing.

Whatever choice they made in software or hardware around GPS is very clearly a sub-par experience compared to the Series 6. On the same route in multiple places is performed like the older Apple Watches, cutting corners Mario-Kart style as it bumbled along. Same goes for a second run as well.

And on the optical heart rate, the Series 4/5 sensor wasn’t bad per se (after initial bugs were sorted out), but the SE using the same sensor showed issues that definitely weren’t seen on the Series 6 in my tests. Obviously, Apple changed the Series 6 sensor for a reason, and undoubtedly accuracy was a piece of that puzzle.

But the lack of always-on screen is sorta the biggest puzzler for me. After all, always-on screens became the defacto norm for high-end AMOLED watches in 2019 (even sooner for some companies). So to revert back on this watch to raise to wake isn’t super ideal.

Anyway, I’m sure there will be folks the SE works for. For example, if you don’t care about sport/fitness, then getting more storage for music, a faster processor, and of course the bigger screen are all worthy additions. But if those features don’t matter to you and fitness does? The initial data isn’t looking super compelling.

With that – thanks for reading!


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  1. Alexander Momberger

    That GPS-smoothing is increadibly stupid! Ray, have you ever had the chance to ask apple about the reason for that smoothing?

    • Jason

      Hi Ray, great read, as usual. Just a couple of autocorrect issues – at the start I suspect it was intended to be “… what Engadget…” rather than that, and it should be “… a staple of Apple Watch…” in the GPS section (just after the Mario Kart references) and Cheers.

  2. Vieri Joan

    If the SE price similar/above the Series 5 in my Country, should I get the series 5 or the SE version?

  3. JJS

    Ray, thank you so much for this absolutely clearing post! You made me safe a lot of money because my intention to get the SE I know for now was wrong…

  4. Robert

    Technically, the claim that the SE uses a “2nd gen HR sensor” is correct – the 4/5/SE sensor is their second generation, as the 1/2/3 used the original, 1st gen. It’s the claim that the Series 6 uses a 2nd gen sensor that sounds incorrect – it’s clearly different from the 4/5/SE packaging. Then again, maybe they just consider the Series 6 as a repackaged 4/5/SE sensor ?

    • Yeah, they have to choose one or the other, but both claims can’t be true.

      I don’t see how any company in the industry would consider the Series 6 the “same sensor”, since it uses a substantially different LED & photodiode arrangement, which would (and clearly does) impact accuracy. Even if a company used all the exact same parts in a different pattern, most would still not consider that the same.

  5. CarlJim

    Hi Ray, thanks for the review. It was what i was waiting to make a decision between the AW6 an AWSE. Anyway, it will be much appreciated to have a test between AW5, AW6 an AWSE through the same track and at the same time. Will you give us that, please?? I know you said that there are differences in both gps and HR, but it will be easier to compare them like that.

    I have 2 questions (more):

    -Do you believe the gps problems can be solved by software updates? I don’t think so as those problems are happening as well in AW5, right?

    -If you could buy one for similar prices? Will you go for the S5 o SE? In terms of GPS an HR accuracy. Or SE is the only way to go?

    Thanks a lot

    • Blu

      Same questions here. In my country the price of SE and 5 are the same, so really appreciate if Ray or someone can answer those.

    • Zepp

      I will buy an S6 over both S5 and SE. This article sealed the deal, although I was almost 100% decided on the S6 already.

      It’s a bit more expensive, but if you use it for 4-5 years does it really matter in the end?

      (Also, it’s not widely known, but Apple offers battery replacements for Apple Watches. I think it’s something like $79 in US. You will get a refurbished “like new” unit back. I have no idea how long they offer that for each model though.)

      I’m using a four year old S2. The battery is still fine.

      My main gripes with S2 (from an exercise viewpoint) are:

      Swooshing…although it’s not that annoying; the distance seems to match my Polar M400 quite accurately anyway in the end.

      Sometimes VERY slow HR lock.

      The biggest issue: there is no heart rate based training in the stock Workout app, at least not in watchOS 6!

      I simply don’t understand the obsession about pace or distance.

      All I really care is that my HR is between xxx – yyy during the run. I’d love to get audio alerts if I’m outside the range I’ve set so that I can slow down, or pick up the pace a bit.

      (Pace is whatever it happens to be on that day, it doesn’t matter at all.)

  6. CarlJim

    AWS6 I wanted to say at the d d of my message. Is it the only choice possible in the Apple department in comparison with Suunto, Polar or Garmin?

  7. RAD

    Ray said:

    There’s no ‘good’ angle to take a picture of multiple Apple Watch sensors due to the highly reflective nature of them and that they have a slight crown to them.

    Possible photo tip: if you are using an SLR (or have one handy) a “circular polarizing filter” is an inexpensive way to remove glare from glass and water surfaces.

  8. Mike

    How’d you even get anything out of the Apple Watch for analysis to begin with? Since the WatchOS7 and IOS14 releases I haven’t been able to get anything out of my AW5. I’m using the stock Workout app and the runs and walks show up on my watch. But, they do not sync over to my phone’s Workout app at all. I also use HealthFIT to sync to Strava and of course nothing’s there and nothing is making it to Strava (the horror).

    • John

      for me everything works as before with AW 5/ios14/watchOS7

    • Mike Richie

      There is a big problem going on. This is just one of the threads on the Apple community forum: link to discussions.apple.com .
      It appears to only be happening with updates, not new devices and clearly is not happening to everyone. I have a Series 3 (Watch OS 7) and an iPhone 7Plus (iOS 14) and new workouts just show a start point in the map and older workouts do not show a map at all. The GPS is clearly working since the distances are accurate for outdoor workouts in running, walking and cycling. In fact, my distance results, compared to my Garmin watch are much better than before the update. I believe the problem is most likely in the new Fitness (old Activity) app on the phone or in the way data is being backed up and restored.

    • Matt

      You just have to repair your watch and everything wiil be ok again 😉 It;s a software glitch.

    • Mike Richie

      Matt, it is definitely a software glitch (and maybe corrupted data) but re pairing did not fix my (or most of the commenters in the above thread) problem.

    • Mike

      Agree. I’ve restarted and repaired my AW5 twice now and it does NOT resolve the issue.

  9. Hap

    Thank you for the thorough fitness first look on the SE! Just wondering have you ever tested how accurate the estimated VO2 max is on the Apple Watch? How does it compare to other trackers and professional measurements if you’ve ever been tested.

  10. andrei

    never had an issue with raise to wake, and I kinda like it. Can’t stand someone else seeing what’s on my watch besides AOD drains more of the battery. For me the bummer is the lack of U1 chip. It might turn out a very useful thing or not. So I will wait and see wha’t going on with U1 (right now not much is going on). my watch3 must be replaced in the near future.

  11. FitGearHunter

    Great review as always. I have but one question: Why are you still using the Whoop?! Noted in the AW6 review as well. That’s so interesting, and exactly what I found – that the HR data is inconsistent and not on point with the workout. So again – are they testing different algorithms on you? Gotta share the insider info!

  12. Alan Rey Mercado

    I’m going to have this to replace my fr645 as my everyday watch. with this price point, this is something that i could justify purchasing to compliment my iphone. together with apple’s excellent customer service this is a good compliment with my iphone. my fr645 that after a year already broke down and garmin’s spotty customer service that favor those who live in the so called first world country, 645 is the last garmin for me. i will still have it repaired and use it for my longer runs, but once its unusable i’m not looking back.

  13. I’ve been pining for an Apple Watch for years, and I think it’s finally just about time to replace my Magellan Echo with something a bit more robust. I had been leaning toward the SE, but your observation of the continuing Mario Kart problem has me rethinking. Two questions should point me in the right direction:

    – Has anyone noticed if the smoothing issue occurs in *third-party* apps in addition to the stock Apple tracker? I have run with iSmoothRun on my phone for about eight years and intend to use the Watch version of the app. I wonder if going that route would alleviate whatever Apple is doing to GPS, or if it’s a system-level effect.

    – I am looking to avoid an additional monthly charge by going with a GPS-only model, and hopefully leave my phone at home. Practically speaking, does that have any real effect on the running experience? Forget music and any other non-running connectivity issues (phone calls, messages, etc.).

    Thank you to anyone who can help!

    • Sam Brown

      You’ll probably still get the smoothing with third party apps if you view the workout in the apple fitness app on the phone, if however you view your runs in the ismoothrun app like you currently do I think they will use their own smoothing algorithm, so it will probably look similar to how your current runs look with your phone. Looking back at some of my old runs with workoutdoors on the watch the smoothing is definitely different, looks closer to garmin maps.

      The cellular version is pretty much just for phone calls and cellular music streaming when away from your phone, it has a few other uses but the gps only version works like you would expect, like all running watches you can leave your phone at home, run with just your watch and sync your workout when you get home, it works well.

    • Thank you, Sam. That’s great info and pretty much the behavior I was hoping for. Much appreciated!

  14. CarlJim

    Hey Ray, any news or more details on the behavior of this watch from your later runs? Some of us are still waiting to make a decision between s5, SE or s6 based on your opinion/data 😉 Thanks a lot. We know you are busy testing many gadgets.

  15. Christopher Watts

    Nice review. Am in the process of deciding whether to go for an Apple Watch or a Garmin device. My main sport is cycling ( power meter and Wahoo head unit), with a bit of running , yoga and strength training thrown in. Due to my job , I can’t wear a watch at work, so it will be mainly evening and night time HR measuring and sleep. Poor battery life compared to the Garmin, makes me hesitant to buy Apple, though I probably will.

    • Paul S

      I assume you have an iPhone, else your only choice is Garmin. Since you can’t wear a watch at work, that solves the battery problem; just put it on the charger while you’re at work. I own an Apple Watch 5 and a Fenix 5+. The AW is a much, much better smart watch. I don’t use my AW for anything fitness related (Edge 830 for cycling, Fenix 5+ for cross country skiing and hiking), but I’ve read it’s usable for casual fitness and have used it once for hiking (Strava app). Since you’re already set for cycling (so far as I’m concerned, no watch is usable for cycling) if I were you I’d get the Apple Watch.

  16. Steve Lamarre

    Hi, I’m a Garmin user so all the data of my rides or runs are fully available for analysis on iPhone, iPad, web browser and easily integrated to Strava. I just bought an Apple Watch SE to my wife and have a hard time trying to do the same with the Watch. The Health app that have the run history is not available on the iPad nor on the web. What is your way to analyse your rides/runs on a bigger screen than an iPhone one? How do you import to Strava. I’m interested in knowing how you can replicate a really user friendly Garmin ecosystem with the Apple Watch. I had an interest for an Apple Watch but now I think that I can live with the bad display of my Garmin 235 instead of having to live with the shortcomings of the Apple Watch…

    • MikeFI

      HealthFit will sync your Apple Watch workouts to Strava and other services. You could also use the Strava app on the Apple Watch.

      Personally I use the Workout app for my walks, hikes and light runs and sync across to Strava via HealthFit.

      I use the Strava Apple Watch app for casual bike rides with the family and bike commuting because it has an auto pause function (Workout app does not).

      Serious bike rides are captured via my Wahoo Element Roam.

    • Steve Lamarre

      Thanks Mike, I always use my Garmin for run and bike. I like the Apple Watch for the tech stuff but it seem that it is not that good for serious training as Apple do not seem to have something like Garmin Connect and you have to use 3rd party apps. I think that I will have to stay with my Garmin for the convenience.

    • Katie

      Hey Steve – The RunGap app will allow your wife to sync her Apple Watch data to Garmin Connect, Strava, RunKeeper, etc. If she doesn’t want to do that, then the HealthView app will allow her to create a “dashboard” page of widgets similar to Connect using the data from her watch that’s stored in Apple Health.

  17. Andy

    Have you been able to test SE mariokarting after Watch OS 7 update? Awaiting your words on it to before I take the plunge.

  18. Tom

    I’ve had an SE for about a week. I’m actually really happy with it. GPS tracks are more accurate than my Fenix 5 Plus.

    HR does sometimes take a short amount of time to lock on but it is minimal. Both GPS and HR probably save fewer data points compared to a AW 6 or Garmin.

    You get the same storage as a 6, same software, and a relatively fast CPU. I think the value is pretty good and I recommend it if you want to save some coin compared to the 6.

  19. JS

    Someone mentioned in another Apple forum that the Series 6 has a new U1 chip and the SE (and earlier series) don’t have it. I’m not super technologically proficient, but could this be the difference in the GPS accuracy of the Series 6 and SE? It’s described as “GPS at the scale of your living room,” but from a quick glance at articles it’s not clear if that factors into route mapping during a run.

  20. A Thom

    The 6 and the SE might both have the same 2nd gen HR sensor, just in a different arrangement. When Apple say “2nd gen HR sensor”, they might just be referring to the components.

  21. There’s no doubt that you can find countless designs for Apple Watch Straps everywhere you turn.

  22. I was thinking about buying Watch SE, but after Your impressions I began to wonder about Watch 6. Maybe I will wait few weeks for Watch 7, and than price of the Watch 6 will drop 🙂

  23. Lars

    Hi Ray, is there a solution for the GPS accuracy in the meantime? While I am very satisfied with the AW SE otherwise, the GPS accuracy drives me crazy. I frequently participate in a 5k parkrun and everytime it would cut edges so I lose .3 to .5k. This is annoying when you try to reach a new 5k PB…
    Would using any 3rd party app for tracking improve the situation?
    Thanks and cheers, Lars

    • I’ve been using the SE as a daily watch for about a month before the AW7, and they’ve clearly made some firmware updates (it’s the same unit that I bought last year) that improved accuracy since last year. I don’t know when exactly, but somewhere along the way.

      In my case, I’m specifically not taking my phone on my runs (or, I’m toggling Bluetooth to disabled *ON THE WATCH*) at the start/end of the runs. If you toggle BT on your phone to disabled, Apple will quietly re-enable it a few mins later to talk to the watch (seriously).

    • Michael

      Hi Ray
      is it fair to say that with updates to Applewatch SE you would have no hesitation to recommend purchasing it in 2022?