My arsenal of smart health and activity trackers has been missing a body composition weight scale. The Fitbit Aria always looked appealing to me because I've been wearing a Fitbit for more than 3 years, but it's getting a little outdated. Several months ago, I was looking at the Polar Balance Scale, the Withings WS-50, the Garmin Index Smart Scale, and a few others. Eventually, I settled on the QardioBase because I already had a good experience with the QardioArm and liked the company's no-nonsense approach to design and health. However, I was unlucky enough to get the first generation, which turned out to be a complete failure from the get-go. It wouldn't even set up properly, let alone weigh or connect to a phone. The QardioBase went back into its box, never to be seen again, and I was back to browsing for smart scales.

That's when I read the announcement for the Withings Body and Body Cardio and knew I wanted to try one of them out. Withings knows its scales well and has been improving generation after generation. Its products have been favorably reviewed and this Body lineup is technically the third generation after the WS-30 and the WS-50. Withings has also plunged deep into connected health and home gadgets and been expanding its portfolio with products interesting enough to garner the attention of Nokia who decided to acquire it.

The most fascinating thing about the Body scales though, aside from the brand's good reputation and all of the scales' features, is how well Withings plays with others. The company has direct integration with MyFitnessPal, RunKeeper, Nike+, and Nest, but it also has Google Fit support, and an IFTTT channel for even further connections. These are not just smart scales, they're also part of a smart service that knows how to work with your whole arsenal of connected devices.

My review here focuses on the more expensive $179.95 Body Cardio scale, which does heart rate and Pulse Wave Velocity measures. But aside from a few cosmetic differences and the lack of these two values, the regular Body can do everything else at a cheaper $129.95.

The Good

Design Body Cardio is a very minimal yet gorgeous looking scale.
Multiple users 8 persons can be automatically recognized by the scale.
Battery life About 1 year on a single charge, battery rechargeable via MicroUSB.
Connectivity Works over Bluetooth or WiFi.
Health Mate app It looks great, works well, and even uses Google Smart Lock.
Accuracy Weight measurements are accurate and body composition details don't fluctuate too much.
Integrations Withings works with Google Fit, IFTTT, MyFitnessPal, and more.

The Not So Good

Price At $179.95, this is no cheap bathroom scale.
Heart rate Measuring it while standing up isn't a good metric and results in fluctuating and pointless numbers.
Persistent notification Health Mate invades your notification shade if you're using the scale over Bluetooth, and there's no way to remove it unless you block all notifications from the app.
No clear modes You can disable bioelectrical impedance if you are pregnant or have an electronic implant, but it's not immediately clear how to do so.

Beautiful and robust design

The first impression you get of the Body Cardio is from the weight of its packaging. This isn't a cheap light scale, it weighs about 2.6Kgs (5.7lbs) and is superbly built. It comes with an installation guide and a MicroUSB charging cable and that's all you need to get going and use the Body Cardio.

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The whole scale base is made of solid aluminum with little branding on the back. There are no big feet to place this scale down, but two thin long rubbers that help it stay steady on both hard floors and carpets.

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Above the aluminum is a thick layer of tempered glass that hides 9 large horizontal stripes for the bioelectrical impedance and heart rate measurement sensors. There's an aluminum strip in the middle to separate the left and right foot, and a black and white backlit 128x64 pixel display. And if the white color doesn't do it for you, there's a black option too.

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Branding on the front of the scale is minimal with a simple "Withings" in grey below the glass on the bottom. Unless you look at it from an angle, it's almost invisible (check the image above with the manual and cable). The simplicity in design, clean edges, and perfect finishes make the Body Cardio a really beautiful scale that knows how to look good in any modern bedroom or bathroom but can also easily stay inconspicuous when needed.

In my several weeks of use, I didn't notice any issues with cracking while standing on the Body Cardio, or unbalance when getting on/off it or shifting my weight from one side to the other. The finish on the aluminum still looks pristine despite moving the scale a bit around and the glass doesn't show any scratches.

The only button and port on the Body Cardio are found on the right side. The scale has a rechargeable battery that can last up to a year and only needs about 5 hours on a MicroUSB charger to fill up again. That's because it remains off until it detects substantial weight on it (at least 5Kg or 9lbs) and turns on for the measurement and to send the data, then immediately shuts itself down.

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Quick and easy setup

The button is how you interact with the Body Cardio for setup. It turns the scale on and the message "go.withings.com" displays on the screen. That tells you to grab the Withings Health Mate app to continue the setup.

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The steps are pretty straightforward with the scale first connecting to your phone over Bluetooth then asking you to sign in with a Withings account or creating one, and updating the scale's software if it detects a new version available. Finally, you're asked if you want to connect the Body Cardio to a WiFi access point.

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Unlike the QardioBase that I mentioned at the beginning of this post, I didn't face any issues with setting up the Body Cardio. It took about 5-10 minutes to get it up and running, and everything was clear and went smoothly. Here are the screenshots from the app's side of the setup.

I had two small gripes with the process though. One, the app was dead-set on forcing me to enter my height and weight in ft+in and lb. I have spent my whole life using metric units so trying to figure out the equivalents on the spot was annoying. Two, Withings needs you to create another account and doesn't support a Google login.

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Now both of these were later easily remedied. You can press the button on the side of the scale to change the units from pounds to stones and Kilograms and you can also set your preferred units in the app.

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And as far as the account situation goes, Withings is one of the few apps I've used that has implemented Google Smart Lock to log you in on Android devices and Chrome.

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I wish more apps implemented Smart Lock!

Weighing yourself and other measurements

The first time you, or any other new user, steps on the Withings Body Cardio, it only measures the weight. The value is sent to the device associated with your scale either directly via Bluetooth or via WiFi. You'll need another measurement to know the body composition.

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When an unknown measurement is detected, you can create a new user to assign it to.

Multiple users

Up to 8 eight users can be managed and automatically recognized by the Body Cardio based on their body weight. If two users have a similar weight, the scale shows the two names and asks you to shift your weight toward the left or right side to choose which person you want to assign it to.

Users can either be dependent on the primary Withings account, in which case they show up inside the app and you can only view their dashboard with a small graph of their progress. This is good for kids for example. But you can also fully share your scale with another user, so they get an email invite to associate their own Withings account with the measures they take on the scale.

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Multiple users can be managed and viewed within the app.

Things to keep in mind when using the scale over Bluetooth

Even though the Body Cardio can connect over Bluetooth too, it is preferably used on WiFi. I am currently in my mountain house, where I just use tethering for connectivity, so I didn't set that up on the scale and decided to rely on Bluetooth only.

95% of things work as expected, which is fantastic since many other scales only work over WiFi. But your main device, the one the scale has paired with, will need to be near the scale to share the data. Thankfully, the Body Cardio has some local memory, so even if you take a few measures without your phone nearby, they will all be saved and sent to the device whenever possible.

The main annoyance though for me was the persistent notification that can't be dismissed or disabled within the app. You'll either have to block all Withings notifications to get rid of it or just live with it until you connect your scale to a WiFi access point.

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This notification is persistent when using Bluetooth and there's no setting to disable it.

Bluetooth mode also lacks a few details on the scale's display. You won't be able to see the weather (because that's a thing with this scale, really!) or the graph of previous weight values. But those aren't big problems.

Body composition

It took a few measures for me to know the optimal way to weigh myself with the Body Cardio, but after that, it's all been working well. I step on the scale, it turns on, shows me the weight, fat percentage, muscle mass, water percentage, and current heart rate. The scale uses bioelectrical impedance through its multitude of sensors to measure all of these and my experience with it has been rather reliable.

Whether it's on a hard floor or a carpet, the Body Cardio was always within 100-200 grams range from my Braun digital scale and my analog scale. There weren't any big fluctuations beyond what I expected day to day, depending on exercise, food consumption, water retention, and a few other factors that I know influence my weight.

However, I know body fat percentage measures are just approximate at best, regardless of the method used, so my advice isn't to look at the number as a specific value, but to observe the evolution of the body fat % through time on the same scale.

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There's an athlete mode that you can set inside your profile page to let Withings adjust the way it calculates fat percentage if you exercise more than 8 hours per week. However, there's no pregnancy mode so if I ever get pregnant, the scale will not recognize the weight gain as normal in that case. And there's no clear way to disable bioelectrical impedance if you have a pacemaker or if you prefer to disable body composition when you're pregnant. The setting exists, but it's called Fat mass and heart rate measurement under the Body Cardio's settings in the app (second screenshot above). Not too obvious. A description or warning could be much more useful to explain what that toggle does.

Health Mate looks and works great

The Health Mate app is probably one of the best smart gadget apps I've seen on Android, period. While it isn't perfect, it gets very, very close to most Material Design guidelines and is filled with bold colors and clear graphs and elements.

There's a FAB to manually log a measure, full screen splashes to describe some features or set some options, nice animations, and plenty of small cosmetic touches like a beautiful blurry effect behind your profile picture.

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And like I've mentioned before, it uses Smart Lock to log you in automatically and if you don't have a Withings activity tracker, you can use Health Mate and your phone as a basic step tracker.

Graphs for everything

Your measures are kept safe in Health Mate and appear on a timeline as scrollable cards. Each time you step on the scale, you should get 3 cards for weight (including body composition), heart rate, and Pulse Wave Velocity (PWV). You can dismiss any of these cards by swiping them left if they don't seem accurate to you. Or you can tap a card to open the more detailed graphs or lists view.

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Still a long way to go for my weight goal, but at least the trend is downward.

This is where you can follow your progress for weight, body composition (body fat %, water %, muscle mass, and bone mass), and body mass index (BMI).

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You can do a lot with these graphs, like pinch to zoom for more details, or swipe across to catch the different daily values and see each measurement's details.

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1, 2: Finding individual measures. 3: Zooming in to view a larger graph.

Heart rate and Pulse Wave Velocity

The differentiating feature between the Withings Body and Body Cardio is the heart-related data. You'll have to stand mostly still (at least not move your feet) and place the bottom of your feet right after the first horizontal sensor stripe on the scale. I did that every time, but the scale wasn't consistent about its results.

Arguably pointless heart rate measurement

The Body Cardio didn't fail to read my heart rate (HR), it just gave me fluctuating values that went anywhere from 60 to 130. I have trouble understanding the benefit of an HR measure while standing up. If you're up, then it's definitely not your resting HR and it will depend on what exactly you were doing before hopping on the scale.

I admit, some days, I got on the Body Cardio after rushing to get ready in the morning, so the high values were understandable in those few instances. But there were days where it gave me low values when I knew I wasn't completely rested, and days it showed a high value when I wasn't rushing. I didn't compare the values to my Fitbit Blaze, which I now realize would've been interesting, but I eventually decided to not give too much credence to the HR value the scale shows.

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My heart rate measure is all over the place.

Interesting Pulse Wave Velocity measure

Pulse Wave Velocity is a marker of good arterial health. There's a lot of medicine and physics behind it, but let's say that blood moves quicker in your body when arteries are stiff and you have a high blood pressure. However, the blood's speed waves are a lot slower when your blood pressure is normal and your arteries expand and contract smoothly to propel the blood. This graphic explains PWV more than I could with my words.

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You can read more about PWV on Wikipedia, Medscape, or Withings' own website. It has recently become an interesting marker of cardiac health and is being more recognized by medical entities with time as an indicator of potential hypertension and heart issues.

It's remarkable that Withings decided to include this measure in the Body Cardio. PWV is calculated based on your height and the time it takes the blood to reach your feet after its ejected by the aorta. But however interesting PWV is as a marker, where it falls on the Body Cardio is with the lack of objective evidence that the measure you're seeing is actually accurate.

Withings did go beyond what other companies do and conducted a study (PDF) to verify the accuracy of Body Cardio against the Sphygmocor on 111 patients. The result was a correlation coefficient of 0.7 between the two — not too close but not too far either. That and the small sample of 111 patients and the fact that the study was conducted by Withings and not an objective entity mean that you can take your PWV measure on the Body Cardio with a grain of salt.

It's most probably accurate or close enough to the true value, but like with body fat percentage, my recommendation is to not look at it as a specific number, but check its range (if it's way outside the normal values, that's not good) and observe its progress through time on the same Body Cardio scale (if it's rising alarmingly, maybe you're doing something wrong).

Now back to the scale itself. Withings will require 5 heart rate measures to start giving you the PWV, which I'm guessing is to help it calibrate and understand your body better. However, even after 5 measures, there were still days when Body Cardio got my HR well but gave me a "No PWV data collected" card despite me standing perfectly like the diagram shows.

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1, 2: After 5 measures, you start seeing your PWV. 3: But sometimes, oddly, you don't.

PWV is also charted like the other measures taken by the Body Cardio and there's a special help section that explains what it is and how the normal, optimal, and not optimal values change across age and time.

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Whew! Looks like my PWV is normal :)

This finicky measurement ratio along with the uncertainty over the results' accuracy take the PWV from an interesting addition in the Body Cardio to a gimmick that you can't really rely on. Beside, if you're young(ish) and healthy(ish), there's no point in measuring the PWV every day. Every month or year, maybe, but daily measures have no added benefit that I can see.

Beyond Withings, other smart integrations

The Health Mate app works with other Withings health trackers (like the Activité or Pop or Pulse O2) and the company's smart blood pressure monitor, but where Withings really shines is with its openness to integrate with other smart platforms.

First and foremost for us Android lovers, there's Google Fit integration, so your weight measure can be automatically sent to Google Fit. I set that up and it worked reliably with each measurement. Weight can also be logged automatically on MyFitnessPal, which could distribute it to hundreds of apps.

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But the most interesting integration is with IFTTT. When you enable the Withings channel, you can have all kinds of cross-service communication recipes, like logging automatically your weight from the Body Scale to Fitbit, Strava, Google Sheets, Jawbone, and so on. Or maybe even lighting your Hue bulbs when you reach a certain goal.

To smart scale or not to smart scale

If you're interested in following your weight's progress, you can grab a regular analogue scale, a digital scale, a body composition scale, a smart body composition scale, or a smart body composition + heart health scale. That's the highest part of the echelon where Body Cardio stands now.

Most smart and connected scales fall within the $80-$150 price range, so your first question is whether you want to shell out money on something like this or you'd rather manually log your weight. There's a price to this convenience, but arguably, Withings made the best of it. From connectivity and rechargeable battery to the simplicity of use and reliability of sync, this is definitely one of the best connected scales on the market right now, if not the best.

But at $179.95, this is far from being a cheap purchase. Despite the gorgeous design and excellent build quality, the well-developed app with plenty of bonuses for Android users (Google Fit, Smart Lock), the excellent integrations within the vast connected gadgets and services ecosystem (MyFitnessPal and IFTTT), it's tough for me to recommend the Body Cardio now.

You can easily grab the cheaper Body for $129.95 (Withings, Amazon) and get most of the functionality but without the addition of options with debatable usefulness. Heart rate measurement is near pointless while standing up. As for Pulse Wave Velocity, it's interesting on paper, but you can't be 100% sure of its accuracy on the Body Cardio, it's finicky and doesn't get measured reliably every time, and there's no real value in following it day to day.

Withings smart scales do drop their prices sometimes, so if you happen to find the Body Cardio around the same price as the regular Body, go for it. Otherwise, I say save $50 and get the Body instead.

Buy: Withings Body Cardio $179.95 at Amazon, Withings

Health Mate
Health Mate
Developer: Withings
Price: Free