The Good: Continuous heart rate tracking. Slim design. Affordable price. Works with Windows, iPhone and Android phones. Fitbit's massive popularity means you'll be able to join up and compete with friends. Connects with many third-party fitness apps. Automatic sleep and activity tracking. Five-day battery life. The Bad: Design and fit aren't ideal for glancing at heart rate. Not shower or swim-friendly. OLED display turns off after a few seconds, which gets annoying. Heart-rate coaching and goal-setting isn't intuitive. The Bottom Line: Fitbit's Charge HR combines heart rate tracking, sleep tracking and fitness into an affordable, slim band with good battery life. It's a hard combination to beat. Editors' note (August 29, 2016): Fitbit has announced the Charge 2, a new tracker with a larger OLED display and swappable bands. The new model will replace the Charge HR reviewed here.I was a little bit wrong about the Fitbit Charge HR.While I liked it when it first debuted, I thought it could do better. The Charge HR is Fitbit's step-counting band, plus a round-the-clock heart-rate tracker. It tracks sleep at night, exercise during the day, and active heart-rate levels when resting or working out, and it syncs with nearly every major smartphone and computer on the planet.I expected more out of the Fitbit Charge HR's heart rate measuring, and how it translated that data into useful coaching. I wanted more app features, too. And I thought the band itself, a basic black device that doubled as a watch with its little LED display, could have been better designed.Most of a year has passed, and the fitness-wearable landscape hasn't been able to beat what the Fitbit Charge HR does. No heart-rate band costs this little, feels this small, and connects to as good an app. Fitbit folds nutrition-tracking, sleep-tracking, heart rate-tracking, and social challenges with friends into one pretty clean phone experience -- and syncing is fast and easy. The Charge HR fits well and has impressive battery life for its size: over four days, beating most continuous heart rate-tracking bands. And its little LED display-slash-clock is basic, but it's easy to lift your arm and see the time, or tap the display to see steps and other data.New software and firmware updates have improved syncing and tracking, adding automatic sleep and activity-session tracking awareness and making tweaks to how it measures heart rate. It's smoother and better than when I first reviewed it. And it now feels like a truly automatic band.It's the all-in-one fitness band I'd buy, especially for its low price ($150 in the US; in the UK, \u00a3120; or AU$180 in Australia) -- and it can be had even lower if you catch it on sale, which we've seen frequently. It's not perfect, but few wearable gadgets are -- and none of the other watches and bands have been able to beat it at its own fitness game.Editors' note: This review was originally published on January 29, 2015, and updated significantly on November 24, 2015. The rating has been raised from 7.8 to 8.0.Design: Basic, but it worksThe Charge HR looks nearly identical to the older Fitbit Charge, and the discontinued before it. It has an innocuous rubberized wraparound band, with a narrow black LED display that tells time, steps, and other data. That LED display isn't always lit, but you can set the Charge HR to show the time when you raise your wrist, or show time and fitness data by tapping the screen. It's a functional but unattractive everyday watch.The band attaches with a standard watch buckle-type clasp, making it more secure and less likely to pop off. It fits snugly, but sometimes feels uncomfortable on my wrist: an optical heart-rate monitor with green LEDs bulges out of the bottom, pressing against the skin a bit when the Charge HR's properly secured.Fitbit recommends wearing the Charge HR a finger's length above the wristbone on your arm for ideal heart-rate readings, which is farther up my own arm than I prefer to wear things. But I found it generally worked no matter where I wore it.The Charge HR comes in several muted colors; my review unit was black. It comes in several sizes, too, although each can be adjusted significantly. The Charge HR comes with its own proprietary USB dongle for charging, plugging straight into the bottom. Don't lose it.Heart rate: All day on your wristOnce attached, the Charge HR immediately flashes its green LEDs to gather heart-rate data. It does it all the time. That, plus a built-in accelerometer and barometer gather data on steps, heart rate, elevation (steps climbed) and intensity of exercise (walking or running). It works automatically, from the moment it goes on your wrist. The Fitbit Charge HR found my heart rate quickly and held onto the reading, so I could access it quickly by pressing the side button or tapping the display, cycling through to heart-rate mode. Like many other on-wrist heart rate readers, they're more accurate when resting. The reading fluctuated during active exercise. That's true of Apple Watch, the Microsoft Band and many others; it comes with the territory. The Charge HR feels as good as those.