The best body fat readings are done in consistent circumstances: same time of day, same level of hydration. So it’s natural to track resting heart rate, which needs the same restrictions, while you’re at it. Withings Smart Body Analyzer, coming out next month for $150, takes your pulse through your feet when you step on it. It sends that data, along with the estimated body fat percentage of your legs, to an app on your iOS or Android phone. Withings connects via Wi-Fi, Bluetooth, or the new low-power standard, Bluetooth Smart.
We like how Withings has an athlete mode for those getting more than eight hours of exercise per week. Presumably, the device uses a different statistical formula to derive body fat, because other scales with this feature deliver more tailored results.