Here With Alta HR, Fitbit turns its most stylish device into a cardio machine

Fitbit doesn’t quit. The reigning maker of fitness-tracking bands has a new band, the ultra-slim heart rate-monitoring Alta HR, and I got a chance to put it to the test during a spin class at a Midtown Manhattan fitness studio last week. I’ve largely avoided the spin craze until now, but on this particular day I was front and center as class instructor Julianne Hough, professional dancer/singer/Fitbit spokeswoman/cardio queen, cheerfully encouraged the class to pedal along to the blaring pop soundtrack. I wasn’t paying much attention to the continuous heart rate on the Alta HR strappd to my wrist, to be honest, because I was sweating buckets. Did I mention this was my first spin class?

My knees are still killing me, but after more time with the $150 Alta HR, it’s safe to say this might be Fitbit’s most versatile activity tracker yet.

Fitbit launched the original Alta last year as a stylish alternative to regular lineup of chunky trackers, with fashionable interchangeable bands to boot. As its name suggests, the newest Fitbit has an optical heart rate monitor baked in, without adding size or sacrificing style. It looks exactly like the original Alta, but with a better band clasp that uses the traditional buckle style instead of the difficult to close snap-in clasp.

So why didn’t Fitbit just put a heart rate sensor in the Alta to begin with? The company had to make an entirely new chip. It's essentially a smaller version of the one it made for Fitbit's first heart rate-monitoring fitness band, the Surge, three years ago.

Fitbit says the new version of the Alta will appeal to people who haven’t wanted to choose between a stylish band and a powerful fitness tracker. Now they can have both.

A good night’s rest

The Alta HR also adds more powerful sleep-tracking tools thanks to the new heart rate monitor. A new feature called Sleep Stages in the Fitbit app uses your pulse to break down your light, deep, and REM sleep. It uses that data to show you not just how much sleep you get, but the quality of that sleep. That feature is also coming to the Blaze smartwatch and Charge 2 later this month. Another new feature called Sleep Insights will tell you how your daily activity affects your sleep, but that’s not tied to your heart rate so every Fitbit user will see that information with an upcoming app update.

Fitbit has one of the largest sleep databases in the world with more than 3 billion nights of sleep logged, and it can compare your data to your own benchmarks as well as those of other men and women your age.

These features make the Alta HR almost as powerful as the recently released Fitbit Charge 2, which costs the same as the Alta HR. The newest tracker is missing a few features that its chunkier cousin has, like the Charge 2’s connected GPS, which isn’t actually built into the tracker but pulls from your phone. The new Alta is more than 25 percent slimmer than the Charge 2, but its seamless design leaves out the Charge 2’s side button, which means there’s no guided breathing mode and no exercise modes.

But the Alta HR’s deeper sleep-tracking tools, more powerful fitness-tracking features, stylish new classic bands and leather options (with seven new colors in total), and seven whole days of battery life could make it the activity tracker we’ve all been waiting for.

The Alta HR goes on sale in early April and is available to preorder now. Stay tuned for my full review.