Charged Up: Sleep tracking has become Fitbit's most defining feature

Back when fitness trackers took off, sleep monitoring was one of the original headline features for Fitbit, Jawbone and the rest of the gang. But a recent shift in focus to heart rate and exercise has meant the tracking of sleep has somewhat stagnated. Now Fitbit is putting slumber back on the agenda, and devices – including the forthcoming Fitbit Charge 3 – are looking into your sleep deeper than ever before.

Fitbit's Sleep Stages feature is so ahead of everyone else out there that every time a new wearable adds sleep tracking, we at Wareable use a Fitbit as the gold standard to compare against. For good reason too, as Fitbit has tested its sleep tracking up against polysomnography technicians - essentially the best way to track sleep - and found it was 69% accurate. It might not sound that high, but that number is very good by non-EEG standards. Let's also not forget that Fitbit's trove of sleep data has unearthed some interesting questions, too.

It doesn't matter whether it's the years-old Charge 2 or the more recent Ionic or Versa, we've put a number of Fitbit's sleep trackers up against newer devices and the Fitbits continue to come out victorious.

Essential reading: Ultimate guide to the Fitbit ecosystem

No one else can give me as easy access to my REM, light, and deep sleep as Fitbit does. In fact, no one can give me the battery life to be able to record as many nights of sleep in a row without having to worry about charging either.

Fitbit's sleep tracking is so good that I will wear a Fitbit to sleep every night - and only at night - turning it into a device I use for only one feature. However, these defining features can often have halo effects that make them more valuable outside of the use case you're interested in.

For instance, I recently traveled overseas, and I can't necessarily carry a bunch of wearables around with me. I knew I wanted the Fitbit's sleep tracking, especially to see how jet lag affected my sleeping patterns, but did I really want to worry about charging two wearables? Of course not.

So I ended up leaving my beloved Apple Watch at home and instead went all in on Fitbit. The Ionic has won a spot on my valuable left wrist because its sleep tracking wasn't something I wanted to part with. Even though I enjoy using my Apple Watch for most other things, the Fitbit is the one on my wrist.

Fitbit knows sleep tracking has turned into a huge boon for it, which is part of the reason it's diving in deeper with sleep score beta, which makes it even easier for you to get insight and data from your sleep tracking.

Now, I'm not calling for Fitbit to go all out and become a sleep tracking company. But it should recognize how important of a differentiator sleep tracking is for it, and continue to double down on that.