Apple Watch Series 8 review: Laying the groundwork

Car crash detection and ovulation tracking define the subtly impressive new Apple Watch.
Apple Watch Series 8 Review

The Apple Watch Series 8 looks just like the Series 7, but has some interesting new features. Mike Epstein

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It may be hard for some of us to see the virtue of the Apple Watch Series 8. Some people will not be able to tell the difference between it and last year’s Apple Watch Series 7, no matter how long they wear it. At a glance, it offers the same day-to-day functionality, with a few key boosts. A couple of these, like a “low power mode,” are hardware-specific, but most of what you’ll see and appreciate comes from the new version of Apple’s watchOS 9 and will be available on older watches as well. 

And, yet, it would not be right or fair to say that the Series 8 fails to make large evolutionary strides. The Apple Watch Series 8 shows its true colors at the most important times, before birth and death. First, a new pair of temperature sensors allows the Series 8 to chart estimated ovulation cycles, helping people attempting to get pregnant. Second, a new motion sensor, in conjunction with existing components, enables the ability to detect car crashes and automatically call 911 and your emergency contacts. 

While you may not feel its changes every day, the Series 8 offers two niche functions that should make a big difference for people at very specific, important times in their lives. That doesn’t necessarily make for a compelling new upgrade when compared to the past couple of watch models, but it’s a huge “building” year that advances the case for the Apple Watch as a product for years to come.

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What’s new about the Apple Watch Series 8?

In its eighth iteration, the Apple Watch Series 8 doesn’t introduce many noticeable design changes. The larger 41mm and 45mm case sizes of the Apple Watch Series 7 return, offering the same excellent visibility, whether you’re engaging with the watch or merely glancing at a notification on its always-on display. I can confirm that all of the Apple Watch’s core competencies—tracking your heart, monitoring your sleep, showing notifications from your phone, and so on—all work just as well as last year … which is to say very well. As with past models, it’s backward-compatible with all previous Apple Watch bands (though Apple has some new styles they’d love to sell you, of course).

There are a handful of improvements and tweaks to those core competencies, along with some honest-to-god new features, but virtually all of them are enabled by watchOS 9, the newest version of the Apple Watch’s operating system, which is compatible with the Apple Watch Series 4 and up. I’ll talk about the details of some of those changes more in a bit but the important thing to note here is that the Apple Watch Series 3, a very popular model that was on sale for a long time, will no longer receive updates. That leaves the Apple Watch SE 2 as the most affordable model in the line. 

The Series 8 offers the same battery life as the Series 7, up to 18 hours on a single charge, but there’s a new wrinkle this time around. The Series 8 adds a low-power mode, which can keep the battery running for up to 36 hours on a full charge. Entering low-power mode disables some of the watch’s passive functions, such as the always-on display, automatic workout detection, and heart health notifications. As in the Series 7, the battery offers about enough energy to get you through a day and track your sleeping overnight but with very little wiggle room for charging afterward. Low-power mode can be that wiggle room if you can’t find a good time to take the watch off for a while.

Crash detection

Though I hope neither you nor I ever need it, Apple Watch’s crash detection feature is very impressive.  It uses the watch’s many sensors together to confirm a very serious situation very quickly. It’s exclusive to the new line of Apple Watches—Series 8, SE 2, and Ultra—because it requires a new, more powerful gyroscope and accelerometer, which can detect the high force of an impact and distinguish between a car stopping suddenly under control and a crash.

That said, the feature also uses a handful of existing sensors on the Series 8 to confirm a car crash: The microphone should register the sound of the crash. GPS should confirm that you’ve gone from moving at high speed to a complete stop. Our personal favorite is that the barometer should detect a change in pressure caused by the release of an airbag. All of these sensors work quickly in tandem to register the kind of car crash that might leave a person stunned or knocked out and unable to call for help.

When the Series 8 detects a crash, it should raise a screen that lets you know it’s going to call emergency services, giving you 10 seconds to cancel the call. If you don’t, it promises to send your GPS data to EMS, as well as any emergency contacts you’ve specified. It’s a very smart, streamlined process that seems very capable of calling for help faster than the average person would be able to on their own.

Apple Watch Series 8 Review
This year’s bands include this redesigned version of the Nike Sport Loop. Mike Epstein

I say “can” and “should” because I haven’t actually tested this feature, nor have I tested the ovulation tracking, which we’ll discuss in a minute. Based on Apple’s track record, we’re taking it on faith that these features work as intended—we simply do not have the facilities to test crash detection. (That said, we’ve seen that the predecessor to this feature, Apple Watch fall detection, works very well.) For ovulation tracking, it would take a few months of nightly use to test effectively—and a different reviewer, of course, but that we could’ve handled.

Skin temperature sensors

Apple Watch Series 8 also adds a two-sensor approach to temperature measurement, which enables a new ovulation tracking feature. One sensor, on the back crystal, reads your skin temperature. The second, under the display, reads air temperature. Like an active noise-canceling microphone array, the two sensors work together to get a precise read on your average temperature and note any substantial changes. It isn’t capable, however, of “taking your temperature,” as you would with a thermometer—the Series 8 specifically warns you not to use it to see if you have a fever.

How do we get from “takes your temperature” to charting your ovulation cycle? If you wear the Series 8 to bed every night, allowing the watch to regularly record your temperature, it can map out night-to-night (and, by extension, day-to-day) changes in your body temperature. For ovulation, specifically, measuring temperature changes and heart rate will allow the watch to retroactively map a user’s biphasic shift, indicating when they were most likely ovulating.

It’s worth noting that there are already other devices out there with this functionality. Some, like the Ava fertility tracker, have been doing it for some time. The latest Oura smart ring can track your skin temperature, though it doesn’t have dedicated ovulation-tracking support. That said, having it in a device like the Apple Watch, which we’d recommend for a wide array of uses before and after conception, beats spending $200-$300 on another wearable specifically because it has a temperature sensor.

And watchOS 9 makes some great improvements, too …

For those of you who either pre-ordered a new Apple Watch or plan to buy one in the near future, most of the changes you’ll notice will come from the jump to the Apple Watch’s new operating system, watchOS 9. As with every annual OS update, there are a ton of changes, big and small. Here are a few of this year’s highlights.

Afib history

Building on the existing heart rate tracking, Apple Watches with watchOS 9 can record data on Atrial Fibrillation, or a rapid irregular heartbeat, for those who have been diagnosed with the condition by a doctor. On the Health app, you’ll be able to review how often your heartbeat’s out of sync. The app can also provide information that can help you manage the condition.

Enhanced running metrics and Workout views

Apple Watch Series 8 Review
WatchOS 9’s new heart rate zones view puts your workout data in context. (My end table really needs to get to the gym.) Mike Epstein

The Workout app received a nice upgrade in watchOS 9, offering more data views and customization. During a high-impact workout, the Series 8 creates heart rate zones to help you gauge how hard you’re pushing yourself. You can also set multi-phase workouts on timers, so you know when to pick up the pace or slow down before the end of a workout.

Runners, in particular, will benefit from enhanced tracking that measures stride length, ground contact time, and vertical oscillation, or how much you bounce when you run. If you’re an outdoor runner, the Apple Watch will automatically detect when you arrive at a track and prepare for a workout. Even if you aren’t at a track, “Outdoor Run” and “Outdoor Cycle” workouts are set to gain a feature that lets you record your route so you can track your time on a specific run or biking workout time after time.

New Compass app and “Backtrack”

Though Apple has primarily linked it to the Apple Watch Ultra in its marketing, the Series 8 will also get the reimagined Compass app, which gives you the ability to drop GPS waypoints for locations like your home or car, so you can always reorient yourself to find them.

WatchOS 9 also enables a feature that uses GPS to help you retrace your path if you ever get lost. Since it’s GPS-based, “Backtrack” works even if your phone and watch can’t connect to a cellular network, making it very useful for campers and anyone else who finds themselves “off-grid.”

Medications app

There’s an entirely new app, Medications, designed to remind you when to take your pills. Going beyond a simple reminder, the app keeps a list of every medication you take, tells you exactly when to take it, and can cross-check for possible drug interactions when you start on something new (based on U.S. pharmaceutical information).

So, who should buy the Apple Watch Series 8?

Apple Watch Series 8 Review
With the new Compass app, you can retrace your steps using GPS. Mike Epstein

As with a lot of Apple’s products, the general question—“Should I buy an Apple Watch or not?”—remains the same as before the Series 8 launched. The Apple Watch is, overall, the best lifestyle smartwatch you can buy. There are more intense fitness trackers, and dedicated sport watches for hikers and athletes, but the Apple Watch remains the indisputable champ for everyday life. (Of course, that is contingent on you already owning an iPhone.)

Despite the fact that many Apple Watch buyers are still hopping on the train for the first time, the real question becomes, “Should I upgrade to the Apple Watch Series 8 from whatever I have?” This will vary from person to person based on how they use the watch, so my best answer is that you should opt for the Series 8 if you decide to upgrade. The features it adds—particularly the car crash detection—are compelling background functions that are worth spending a little extra for if you’re already in the market for a new smartwatch. I don’t know that it’s enough to warrant running out and buying one, particularly if you just bought in, but it’s enough to endorse the idea that the Apple Watch, as an ongoing concern, continues to move forward.