We like Fitbit's Charge 2 fitness tracker, but there's no question that it has room for improvement -- in particular, it could do with better guidance when you're in the middle of some activities. Thankfully, you're getting just that. A just-launched firmware update for the Charge 2 has added a slew of genuinely practical features highlighted by heart rate and breathing help. There's an upgraded heart rate zone display (shown at top) that makes it easier to tell whether or not your blood is pumping as quickly as it should. If you need to step up the intensity, you'll know with a quick glance. The breathing-oriented Relax mode, meanwhile, now has Apple Watch-style vibration cues so you don't have to stare at the screen while you calm down.