I’m a longtime runner who has completed two marathons. I want to get better, so I won’t stop running for as long as my body will allow. I’m also a longtime Apple Watch user, and the Series 10 is almost the best possible wearable for my needs.
Long-distance running should go hand in hand with a device like the Apple Watch, though some runners will always disagree. After finishing my second marathon in November, I praised the Apple Watch Series 10. Battery life continued to blow my mind, especially under real stress like a long race.
However, the Apple Watch Series 10 has a serious workout problem that I’ve kept experiencing time and again. The Watch will stop recording heart rate readings at several points during a workout. It happens to me during runs and walk sessions. BGR’s editor Zach Epstein deals with the same heart rate reading issues during regular fitness sessions at home.
It’s so bad that we routinely joke about dying while exercising. I’ve been experiencing it for months to the point where I started questioning whether the Apple Watch Series 10 is misleading me when it comes to other heart rate readings. I use the Watch to monitor health parameters for 23 hours of the day. If the workout heart rate readings are off, who is to say that the rest and sleep readings are accurate?
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It turns out there’s an even bigger issue with my Apple Watch Series 10 that I never saw coming. I’ve reached a point where I regret replacing my Apple Watch SE 2 with Apple’s newest wearable. Maybe I should have stuck with the mid-range model, even if that meant getting a replacement battery or an entirely new device.
You see, I’ve found an algorithm issue that can ruin training sessions for runners with even bigger ambitions than mine, which boil down to getting out of the house more and moving my body. Never in a million years did I expect to see such nonsense in the Fitness app of my iPhone, but I did, and I’m going to show you what happened. And yes, I suspect the heart rate readings issue plays into the error you’re about to see.
The new problem
While most of my runs are rather boring, as I look to safely increase my mileage every week, I also incorporate faster runs to remind my body to actually make an effort. These include speed runs, which should help me improve my personal record (PR) across various distances.
One of the exercises I do is run strides every now and then. I should do it every week, but it doesn’t always happen. The current exercise I’m on is something I set up on the Apple Watch SE 2 this summer, and I complained about how annoying it is to set up on the tiny screen.
It involves running a total of 10km, of which the Warmup and Cooldown account for 3km each. The 4km in the middle is split into 10 sessions. These are the strides where I run fast for 100m, then walk 300m.
In what follows, I’ll compare a session in August with the Apple Watch SE to one with the Apple Watch Series 10 from Saturday.
Here’s a quick summary of each session. The first thing you’ll notice is the big heart rate discrepancies. The Apple Watch SE 2 perfectly captured the heart’s rhythmicity during the strong effort strides. The Apple Watch Series 10 makes it look like there’s something wrong with my heart. Also, notice that the Apple Watch Series 10 misses heartbeats in several workout segments.
Image source: Chris Smith, BGR | Image source: Chris Smith, BGR
Next, I’ll give you a look at the intervals in the workout. In the August session, you’ll notice it recorded everything perfectly. We’re looking at the final seven Work/Recovery pairs in the screenshot and the Cooldown session. But move to the Apple Watch Series 10, and you’ll notice the big problems.
Image source: Chris Smith, BGR | Image source: Chris Smith, BGR
The wearable missed a Recovery session. Well, what the Watch did was to combine a Work and Recovery session and give it a mind-boggling time. If that’s not enough, the Apple Watch Series 10 missed the entire Cooldown session, which amounts to 3km of heart rate data.
I blame it on the heart sensor
Strangely enough, when looking at the splits, the Apple Watch Series 10 recorded times for the final 3km and gave me heart rate data. How can that even be?
Image source: Chris Smith, BGR | Image source: Chris Smith, BGR
My heart rate shouldn’t have been that high, as I was cooling down, so I was running at a much lower pace. I caught the Apple Watch Series 10’s heart rate sensor not showing a reading towards the end of my Cooldown segment.
But if the heart rate was up because I was running too fast, why didn’t the Watch correctly register the Cooldown segment? It should have had all the information to do so.
Here’s another comparison between the heart rate recordings for the August and January sessions. Notice how the Apple Watch Series 10 doesn’t register post-workout heart rate correctly, which is another big issue with the wearable.
Image source: Chris Smith, BGR | Image source: Chris Smith, BGR
I’ll also point out that I would have never encountered this Workout algorithm issue if it weren’t for the heart rate readings problem. I know they’re there, so I always check my heart rate readings after any fitness session.
With all this in mind, I feel like I can’t trust the Apple Watch Series 10 to keep track of my health and fitness data accurately. The wearable’s inability to measure heart rate readings is mind-boggling. But I never expected it to mess up a custom run like it happened on Saturday.
Nothing else has changed
I’ll add that this wasn’t my first strides session with the Apple Watch Series 10. I haven’t encountered the Work/Recovery problem above before. I went back in time via the Fitness app to check.
Also, I’ve been on watchOS 11 beta on both wearables. I have the same type of watchband, and the Apple Watch Series 10 sits just as snuggly on my wrist as the Watch SE 2. I wear the same running clothes, and I enable the Water Lock when I have long sleeves to prevent accidental touches. Yes, it happens on the Series 10 and it happened on the SE 2.
Apple Watch Series 10 health sensors Image source: Christian de Looper for BGR
All I can hope is Apple fixes these issues with software updates. If not, I’ll always question the data the Series 10 can offer and its ability to help me improve my running game. I’ll have a good reason to ditch the Series 10 as soon as the Series 11 comes along.
I might even consider a downgrade to the Apple Watch SE 3 that’s reportedly coming this year. I didn’t think I’d say that when I first experienced the Series 10.