Article updated on September 24, 2020 at 5:00 AM PDT

Galaxy Watch 3 review: A stunning smartwatch with SpO2 tracking and ECG

Samsung's new Galaxy Watch 3 has a new FDA-cleared electrocardiogram feature and can measure blood oxygen levels on demand, but battery life is less than ideal.

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Vanessa Hand Orellana
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Vanessa Hand Orellana CNET Senior Editor
As head of wearables at CNET, Vanessa reviews and writes about the latest smartwatches and fitness trackers. She joined the team seven years ago as an on-camera reporter for CNET's Spanish-language site and then moved on to the English side to host and produce some of CNET's videos and YouTube series. When she's not testing out smartwatches or dropping phones, you can catch her on a hike or trail run with her family.
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Samsung's Galaxy Watch 3 has a lot working in its favor. It's one of the best-looking smartwatches out there, with a physical rotating bezel and bright, circular AMOLED display. It also brings new health and fitness tools such as a running coach, better sleep tracking than earlier models, blood oxygen monitoring and an electrocardiogram (EKG or ECG). But at $399 (or higher) it's on the pricier end of the smartwatch spectrum, and battery life on the smaller version is disappointing. 

Read more: Samsung Galaxy Watch 4: Samsung aims for the ultimate Android watch

Watch this: Galaxy Watch 3 stands out from the rest

Looks go a long way with this watch 

I was already a fan of the original Galaxy Watch with its round face and physical rotating bezel, and the Watch 3 looks even nicer. It has a bright, beautiful AMOLED screen that's easy to read even in broad daylight. It's also useful if you're on a run and need to quickly check your stats during a workout. The screen can always be on if you need it, although it'll cost you in the battery department (more on that later). I like navigating the interface with the rotating bezel instead of smudging the screen with my fingers. 

Gazing at the Watch 3 on my wrist, I think it could almost pass for a traditional analog watch thanks to its classic design. The smaller bezels mean the screen is bigger than the original's even though the body of the watch has gotten smaller. It still bulges out from under the stainless-steel frame, however, making it thicker than I'd like and not as comfortable to wear at night as the Galaxy Watch Active

I tried out the bronze 41mm version (the watch also comes in a 45mm size), with the tan-pink leather straps -- a welcome step up from the silicone straps on the original Galaxy Watch and Galaxy Watch Active series. The bronze is a lot less flashy than the gold of the original Galaxy Watch, and it looks softer and more flattering on my wrist. If you're planning on using it for working out or swimming (or, in my case, bathing small children), you may want to invest in a sports strap as well. I can see the leather getting worn after a while due to frequent contact with water.

A staggered rollout of its health features

Aside from its looks, what really made the Galaxy Watch 3 stand out for me was its impressive list of new health features. It has ECG, an SpO2 app that measures oxygen saturation in the blood, a blood-pressure monitor, fall detection, advanced sleep tracking, period tracking and a detailed post-run analysis. But I have to admit I was a little skeptical as to whether Samsung could deliver on all of these promises. The Galaxy Watch Active 2, for example, also launched with an "ECG feature" which is still pending over a year later. The blood-pressure feature from the original Active was unreliable at best when we tested it and calibrated it against a blood-pressure cuff. 

Samsung has since received FDA clearance for its ECG feature which can also screen for signs of atrial fibrillation (AFib), and rolled out the feature to both the Watch 3 and the Active 2. But blood pressure that's still pending FDA clearance in the US. (Blood pressure is only available in South Korea at the time of writing.) 

Tracking blood oxygen levels on the Galaxy Watch 3 

Samsung has had SpO2 tracking on past Galaxy devices like the S10, but I was excited to test it out on the watch to see how it had improved. Apple's new Apple Watch Series 6 also tracks blood oxygen levels on demand,  while other smartwatches from Fitbit and Garmin use blood oxygen levels for sleep analysis or to determine VO2 max during exercise.

Tracking blood oxygen has become especially important during the coronavirus pandemic. People with COVID-19 can experience shortness of breath and serious dips in blood oxygen. 

Doctors and hospitals use pulse oximeters placed on the tip of the index finger to measure blood oxygen levels, but these have become a hot commodity during the pandemic as many patients experiencing shortness of breath have turned to these small sensors to determine whether or not to head to the emergency room. 

To test accuracy of the SpO2 app on the Galaxy Watch 3, I took a side-by-side reading using a medical-grade pulse oximeter and both gave results within a few points of each other (98 and 99). It also took a few minutes more to get a read on the Watch 3 and you have to position it correctly on your wrist for it to work. 

Because my oxygen levels were within the healthy range, it's hard to know whether the Watch would be as accurate as the pulse oximeter in the lower ranges as well. It's also important to note that any watch or consumer tech device should only be used as a starting point, never in place of a physician and medical care. 

Like its predecessor, the Watch 3 can monitor stress levels using your heart-rate data. The test takes a few seconds and requires you to keep your arm still. Once it has the information it needs, it'll grade levels on the stress spectrum and give you the option to go through a minute of breathing exercises to help get your rating down.

I took my stress test while on deadline writing this review and it detected very low levels, so I'm a bit skeptical about its accuracy. 

It's also added menstrual cycle or period tracking: You enter the data in your watch and it syncs with the Samsung Health app, which can give you information about your next period and predicted fertility window. The feature isn't native to Samsung and is powered by the Glow app, which was already a relatively established name in the menstrual health tracking category and one I'd used before. 

The other big health feature exclusive to the Galaxy Watch 3 is the trip-detection feature, which I hope I'll never need. If the watch detects that you're not moving after a hard fall, it immediately calls your emergency contact and shares your location. It's not on by default, so you'll have to set it up from the advanced settings option on the Watch 3 and designate an emergency contact. I tried activating it by falling on my bed a few times but I was unsuccessful. The Apple Watch (Series 4 and later) has a similar feature called fall detection that's actually saved lives.

CNET screenshot/Samsung

New ways to work out with the Galaxy Watch 3 

Despite its dressed-up exterior, the Galaxy Watch 3 doubles as a fitness tracker. It tracks 40 different workouts, including swimming (both indoors and outdoors) and will automatically detect and track seven of those workouts. Within about 10 minutes of my starting my walk, I received a notification to start a workout and it gave me credit for the 10 minutes prior. 

A heart-shaped dashboard shows you a breakdown of your active minutes, calories burned and stand time during the day compared with your target. 

I took it on my usual 3-mile run alongside the San Francisco Bay without my phone, and I found it to be fairly accurate at displaying my distance, pace and heart rate. 

You'll have to tweak the settings to display the information you want at a glance during your run, because the default doesn't include heart rate, which I personally like to have on hand. But I liked that it showed me a map of my run and a breakdown of my heart rate zones at the end of the run. It told me I had sustained my maximum heart rate for 2 minutes during the uphill portion of my run. You can also access this data after the fact on the Samsung Health app.

It also has a few bonus features for runners. The first is a running coach, the same one that debuted on the Active 2, which provides real-time feedback about pace and form during a run. Instead of starting a normal run, I selected the running coach on the watch and plugged in my earbuds. A robotic female voice told me to start my warmup. The voice gave me pace alerts throughout the run and generic tips about lengthening my stride and landing on the front of my feet instead of the heel. Be warned that using the running coach will drain the battery a lot faster than if you are tracking a regular run.

What's new to the Galaxy Watch 3 is a post-run analysis, with details including flight and contact time, asymmetry and stiffness to help identify areas of improvement. It's not as comprehensive as the data you'd get on a dedicated running watch such as the Garmin Forerunner, but it could help if you're training for a race or just looking to get more out of your usual route. 

Apparently my "stiffness" needed improvement. Good to know, but it'd be nice to get this feedback live from the running coach so I could have adjusted during my run. It can also calculate your VO2 max, or maximum oxygen consumption during exercise, to give a sense of your overall fitness and tells you what your percentage is within your age group. This is the same metric you'd get if you were doing a VO2 max test in a lab on a stationary bike or treadmill, wearing a mask that measures oxygen exchange. I'm yet to compare them to determine whether or not the reading I got on the Galaxy Watch 3 was accurate. 

Mitchell Chang/CNET

Another first on the Galaxy Watch 3 is a feature that lets you sync it with home workout videos you can control from your wrist. I wasn't really a home workout videos kind of person before March, but I think the global pandemic has made us all rethink how we exercise and I've since been doing a lot of Pilates and yoga classes on my TV. Having the workout on my wrist was a big step up from my usual routine. 

I selected an abs program on the Health app, which consisted of three 15-minute workouts during the week, and was able to cast the first of the series on my Samsung TV and and follow along with my watch. The watch vibrated to let me know when it was time to move on to the next exercise and let me pause with a press of the button when I had to readjust my position. Plus it gave me the appropriate calorie credit at the end of it (or at least what I think is appropriate based on similar previous workouts). 

This is not the first watch to offer training prompts from your wrist:  Fitbit's Premium account gives workout videos that sync with the Versa , and there are third-party workout apps for the Apple Watch. But it's nice that Samsung offers it natively and for free. My one complaint is that the workout I chose had the same robotic woman's voice as the running coach guiding me through the workouts -- and let's just say she's not exactly motivating when you're trying to hold a plank for 60 seconds. 

Sleep tracking finally makes sense on the Galaxy Watch 3

One of my biggest complaints about the sleep tracking feature on the original Galaxy Watch was that it provided little context about your sleep habits, especially for if you don't know much about sleep to begin with. 

The Watch 3 has learned a lot from the mistakes of its predecessors, and now gives a more comprehensive look at your night. It gives you a full breakdown of the stages of sleep (light, REM, deep), and compares yours with a normal range. It also gives you a score based on these factors. 

I've never found the score to be helpful, but having the context of seeing my data compared with a normal range helped me figure out how to get the most out of my sleep. While my total sleep time was good, I found I wasn't spending much time in "deep" sleep compared with what's typical. I tried going to bed an hour earlier, and though my total sleep time didn't change, I was able to extend my deep sleep time and felt more rested in the morning. 

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The basic smartwatch features, but no MST for Samsung Pay

I tested the Galaxy Watch 3 with an iPhone 11 Pro and a Galaxy S20 Ultra and, while it worked well on both, some of its features, which include text responses and mobile payments, are only available for Android users. The Watch runs on Samsung's own Tizen operating system, which is easy to navigate and offers a lot more customization than some of its competitors. You can set widgets and rearrange apps right from the watch screen.

You can type, scribble, dictate or doodle a response and take calls from your wrist. It doesn't have a huge selection of third-party apps (Spotify and Strava are among the few), but it does receive notifications from most of them including Facebook, WhatsApp and even CNET news alerts.

With Spotify you get full music control, offline listening for Premium subscribers and streaming over LTE (you'll pay about $50 more for the cellular version of the Galaxy Watch 3). 

The Galaxy Watch 3 has Samsung Pay, but sadly it's NFC-only and the feature will only work at NFC-enabled terminals. The Galaxy phones and  Gear S3  have MST technology so you can use them for contactless payment at nearly all credit card terminals with a magnetic strip. 

Battery life is disappointing

Samsung says the battery on the Galaxy Watch 3 will last for up to two days, which it can, but there are a few caveats. For starters, this claim only applies to the larger 45mm version of the watch. I tested the smaller, 41mm version and Samsung says this size will last closer to a day and a half with "normal use." As always, mileage may vary depending on how you intend to use it. 

With the always on display set to auto brightness, tracking a full night of sleep and taking it on a 30-minute jog (without my phone) I only just made it to the 24-hour mark. 

The watch offers some battery-saving tips including turning off the always-on feature, limiting the screen timeout and turning off location data. I made those changes and the watch lasted a day and a half when I didn't have time for a run and had the always-on screen off, but I feel like those features should be factored into Samsung's claim.

I was also disappointed to find that the watch doesn't come with its own USB wall adapter, just a cable with the magnetic charging puck, but the upside is that you can charge it on any Qi compatible wireless charger, or get a quick boost on the go using the Power Share feature on Samsung's Galaxy phones (S10 or later). 

A good-looking smartwatch with great potential

The Galaxy Watch 3 has come a long way in terms of its features and user experience. Starting at $400 for the base 41mm model, you're getting a premium-looking smartwatch that can finally keep up as a fitness tracker. But the Watch 3 won't feel fully finished until it can deliver on all of its health features.

If you're not too attached to the design, or the physical bezel, you might also consider the Galaxy Watch Active 2, which shares a lot of the same features for about $200 less.

First published Aug. 10.