Fitbit has the worst luck. This spring it released an affordable, outdoorsy fitness tracker just as the ongoing Covid-19 pandemic forced many people to stay home. Now it has released the Sense, which has a new stress-management tool to help cope with—in my case—said pandemic, racial injustice, life-threatening wildfires and toxic smoke, and the disaster that is remote schooling.

Last week, I took the Sense’s stress test in a hotel room on the Oregon coast, where my family and I fled to briefly escape Portland’s hazardous air quality. I got a Stress Management score of 93. I found that to be remarkable, considering I was extremely stressed, not sleeping, panic-spiraling over my kids’s blackening lungs, had been trapped in my house for over a week, and had eaten only French fries for the past three days.

A good fitness tracker doesn’t just have highly sensitive sensors that collect tons of data. It also displays that data in an easily digestible way and provides simple, actionable advice. While the Sense does measure new biometrics, like measuring your blood oxygen and taking your stress levels through electrodermal activity (EDA), I’m not sure it actually helps you.

Too Much Trouble

The Sense is a good-looking fitness tracker. The square face has gently curved corners, no inscribed “fitbit” at the bottom, and a glowing AMOLED screen that shows images in well-lit, striking detail. As is the case with all of Fitbit’s trackers, it also comes with a staggering variety of accessories. I like the sports wristbands, but with the Sense I opted for the woven coral, which I would not recommend as it showed dirt within a few days.

Fitbit also has a variety of proprietary faces, and a bunch of well-designed, and less well-designed, user ones. That didn’t really matter to me, though, since the Sense can only measure your SpO2 blood oxygen levels while you’re sleeping, and if you have the specific SpO2 face loaded on your watch.

I’ve tested other wearables that measure SpO2. None of them require you to have a specific watch face. It’s not that the SpO2 face is bad, but what if you want to take advantage of that beautiful screen to have flowers or your Memoji on your watch instead? (I’m kidding. Take that Memoji off right now.) When I asked Fitbit representatives about this, they said that they do intend to address this issue with updates in the coming months, but so far, you’re still stuck with it.

It doesn’t take much time to load a different face on your watch, but I would not be able to remember to switch it back before going to bed, so I just left it on.

The SpO2 face has a scale that lets you see at a glance whether you have trouble getting enough oxygen while you sleep. Over a week, I never got a score below 94 percent, which both I and the Sense registered as “fine.” It’s difficult to take an SpO2 measurement while you’re asleep, but I did cross-check with a fingertip a pulse oximeter to verify that the Sense’s HR and SpO2 measurements were reasonably accurate, which they were.