While smart scales have been around for centuries, body composition analysis is still a fairly new feature for wearables. Example, the Samsung Galaxy Watch 4 was the first smartwatch to include the feature natively. Amazon’s Halo Band was the first fitness tracker with the feature. Both have been launched within the last two years. Meanwhile, Apple has yet to tackle body composition. For Apple Watch owners, you should turn to accessories like the $149 Aura Strap 2.
Like a smart scale, the Aura Strap 2 determines your body composition via bioelectrical impedance analysis (BIA). BIA works by sending a weak electrical current through your body to calculate your body fat percentage, lean muscle mass, water, and sometimes niche metrics like bone mass. This particular band measures fat, muscle, water, visceral fat (the dangerous kind of fat), proteins, lean body mass and minerals (a proxy for bone mass).
Compared to the company’s first version of the device, it’s 20 percent slimmer and 5 percent narrower. The measuring process has also been simplified. Instead of doing three steps on the original Aura band, all you need to do is touch the electrode of the band with your palm and wait 30 seconds. These design changes reportedly allow Aura to capture 16 times more data, and Aura Devices claims the second-generation band delivers about 95 percent accuracy compared to a DEXA scan — the clinical gold standard for determining the body composition.
That’s already a major overhaul, but the Aura Strap 2 also changes how you put it on. Instead of buckles, it now opts for a stretchy band similar to Apple’s Solo Loop band. That can be a pro or con. If you mainly use the Apple Watch for health tracking, you probably already know how important fit is. Loose fits give inaccurate readings, so you want the BIA sensor to rest flat against your skin. That’s harder to do with an elastic band. Out of the box, the Aura Strap 2 comes with the medium strap pre-installed and three additional sizes in extra small, small and large. The medium strap did not fit my small bird wrists. Neither does the little one. Luckily the extra small did the trick – although I have friends with wrists even smaller than mine. If your wrist doesn’t quite fit on one of the four straps, you’re out of luck because there’s no way to adjust the strap.
But even though the extra-small band fit my wrist, it was a pain to stretch over my hands. I have more than average hands, and there’s only so much you can stretch the leash. (I can use an iPhone 12 Pro Max on my own with no problem, and my fingers can stretch nine keys on a piano.) Fortunately, the company says it’s safe to enter the shower and pool, meaning you can. don’t have to do. take it off more than once a day. So while I normally take my Series 7 off to shower – you need to let your wrists breathe, folks! — I kept it on to avoid taking the belt off. I was also afraid to put the belt on in the morning and take it off at night. I admit this could be an issue specific to my body, but it’s something to watch out for if you have large hands.
Another problem with the band: to change the size of the band, you have to open the case that houses the battery and electrode. The bad thing is that you can’t just open it with your fingers. The strap comes with a small pick that you use to wring it open, but if you’re anything like me, you’ll probably lose it in seconds. But at least you can also use a credit card. This is annoying if you have to try several tires to find the right size, although it probably isn’t a big deal outside of installation and when you have to replace the battery yourself. Aura says the coin cell battery lasts about six months if you measure once a day. Whether that’s true I can’t say, since I haven’t been using the band that long. However, after about a week of testing with 2-3 tests per day, I still have about 76 percent left.
Furthermore, the Aura Strap 2 is refreshingly easy to use. There are clear instructions on how to measure both in the iPhone app and on the watch itself. To take a reading, simply place your palm against the electrode with the Aura app open on the watch. Aura recommends standing with your arms in front of your chest — as if you’re about to do a Russian squat dance without the actual squat — but that’s it.
This is a huge step up from the Galaxy Watch 4. When I checked out the BIA feature on that watch, Samsung gave me a laundry list of things to check to get an accurate reading. That list included checking that I wasn’t menstruating or wearing jewelry. It was annoying to use when you wore the watch on your right wrist, like you had to reach around to access the buttons† None of these were an issue with the Aura Strap 2. Although it was recommended to measure around the same time every day, I didn’t have to worry about my period, my jewelry, or which wrist I was wearing the Series 7 on, because you Apple can adjust the direction of your watch.
My results were also consistent from read to read. They also roughly match the results I got on the Galaxy Watch 4 and the Amazon Halo Display† However, unlike those devices, the Aura app gave me a much better context for how these metrics relate to each other. Every other device has told me I’m overweight or obese based on body fat percentage. While body fat percentage is more useful than BMI, it is an incomplete picture. For example my waist to hip ratio — another method of measuring your risk of heart disease based on your belly fat — falls well within a normal range. Also, my smart scale generally puts me at 27-31 percent body fat. In short, you should always keep in mind that these devices can help you measure progress, but they may not be accurate when it comes to your specific health.
That’s why I was impressed when the Aura app said that even though my body fat percentage was a little above the normal range, I generally had a “good balance of fat and muscle.” In general, you don’t get much more than straight numbers with body composition features. I also appreciated how the app described each stat and how to interpret it. For example, my visceral fat percentage was 1 percent. Normally I would consider that an excellent thing. However, the app noted that having visceral fat below the normal range could mean not having enough for my physical needs and checking with my doctor if my visceral fat was out of range for an extended period of time. It also explained that the “norm” was based on the general population and didn’t necessarily take into account my individual metabolism, lifestyle choices, or my personal standards.
If you have a specific body goal — be it to lose weight or get hung up on — the Aura app will also contextualize where you are and how to get there. I set my goal as an “athletic” body with muscle growth. The app, in turn, told me I’m already about 80 percent of the way there and recommended increasing my calorie intake by 10-15 percent, adding more protein to my diet, and no more than three workouts a week. to do.
The best part is that weight is not a big focus of this app. You do have to enter it initially, but even if you set your goal to lose fat, it never advises you to ‘lose weight’. Instead, it recommends reducing your carbohydrate and sweet intake for two weeks and exercising.
But while I appreciated the extra analysis and context, I didn’t like that much of it is behind a paywall. If you want monthly fitness and nutrition reports, guided workouts, or a new feature that lets you chat with a personal trainer, you’ll have to pay $9.99 per month or $79.99 per year. I can’t say definitively if the extra fee is worth it as I tested a pre-launch version of the app. The workout library I had access to was simple and easy to follow, but limited to one workout per body area and skill level (beginner, intermediate, advanced). Likewise, I didn’t get the full monthly report experience as I’ve only been testing for a few weeks. You are already spending $150 on an accessory. Adding a subscription makes business sense, but paying is another thing. And people inclined to buy this device are probably already paying for multiple fitness-related subscriptions.
In the end, I was pleasantly surprised by the Aura Strap 2. It’s not perfect, but then again, there are few accessible body composition gadgets out there. What sets this apart is a better app that provides holistic insights and context. It’s admittedly a niche product, but if you’re an Apple Watch owner interested in changing your body composition? You could do much, much worse.
Photography by Victoria Song / The Verge