Body mass index, VO2 max, resting heart rate — every year, it seems like there's a new metric that will supposedly give you the best look at your health. Now, Withings' new smart scale, the Body Cardio, will tell you your pulse wave velocity, which provides insight into how healthy your arteries are. But how useful is this new measurement, and is this scale worth $179?
The top of the Withings Body Cardio is white, but it has a silver strip running vertically down the middle, and faint off-white bands that run horizontally across its face. (A black version of the scale is also available.) At the top is a 2.6 x 1.75-inch LCD display that has a nice, bright backlight that turns on automatically when you step on the scale.
Credit: Jeremy Lips / Tom's GuideThe Body Cardio scale works on both hard surfaces and carpet, which is nice if you don't want to keep it in your bathroom. At nearly 13 x 13 inches, it's about the same size as Withings' WS-50 scale, and should be plenty large enough for all but the longest feet.
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The cool new health metric that the Body Cardio scale measures is called pulse wave velocity (PWV). This is the speed at which vibrations generated by your heartbeat spread through your arteries. If your arteries are elastic (as they should be), your pulse wave velocity will be lower. If you have stiff arteries — which are associated with hypertension, high cholesterol and other cardiac issues — the number will be higher.
Credit: Jeremy Lips / Tom's GuideAccording to Withings, a normal PWV for someone between ages 30 and 40 is about 6 to 7 meters (20 to 23 feet) per second. As you get older, your PWV will increase by 0.1 m/s per year. However, the company is quick to note that its scale is not intended to be used to diagnose or monitor any disease. (I registered 6 m/s, in case you were wondering.)
The one metric not shown on the scale is pulse wave velocity — which seems like an odd omission, considering it's the marquee feature.
Like Withings' WS-50 smart scale (which the company is discontinuing), the Body Cardio measures your weight, body mass index and resting heart rate, and will also show you the local weather conditions. However, the Body Cardio scale also measures your muscle mass, total body water percentage and the number of steps you took the previous day. Through Withings' app, you can customize which of these measurements appear on the scale.
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The scale performed as expected, providing a wealth of data about my overall fitness levels. However, the more data you want to see on the scale, the longer you'll have to stand on it. My weigh-in sessions lasted upward of 40 seconds, which is a long time in scale terms.
Credit: Jeremy Lips / Tom's GuideAlso, the one metric that's not shown on the scale is pulse wave velocity — which seems like an odd omission, considering it's the marquee feature of the Body Cardio. You can only see your result in Withings' app. You also need to weigh yourself at least five times before it will give you this reading.
It took about 10 weigh-ins before the app showed me my PWV. Annoyingly, it doesn't appear in the main feed of all the other data gathered from the scale; I had to click through to another page.
The Body Cardio can be connected to your Wi-Fi network, so after the initial setup, you don't need your smartphone nearby to ensure your measurements make it to the Withings app. It's handy.
Unlike most smart scales, which use AA or AAA batteries, the Body Cardio has a built-in battery that will last up to a year; a small micro-USB port will charge it back up. I'm surprised it's taken this long.
At $179, the Body Cardio scale is nearly $70 more than our next favorite scale, the Fitbit Aria. But the Body Cardio could be worth it for those who want to check their arterial health, among other metrics.
Credit: Jeremy Lips / Tom's GuideKeep in mind, though, that the scale is not a medical device, and shouldn't be used as such. Therein lies my main issue with the Body Cardio: How often do you really need to check your arterial health? And if it's that bad, you'll want to use a more precise device to keep tabs on your health.
If you don't care much about pulse wave velocity, Withings will also sell another scale, called simply the Body ($129), which will measure full body composition and weight, but not heart rate, pulse wave velocity, CO2 or temperature readings. For most people, that will probably be enough.