PHOTO: Jason Cipriani/CNN
(CNN) —  

Apple just launched the Apple Watch Series 6, the first model with the ability to measure your blood oxygen level (Sp02), in addition to electrocardiogram (ECG) readings. Samsung’s Galaxy Watch 3 can also take Sp02 readings, and an upcoming software update will add an ECG feature.

For its part, Fitbit recently announced a couple of new devices, one of which has more sensors and health-related features than any other Fitbit. The aptly named Sense ($329.95) is available to preorder now, with deliveries starting by the end of the month.

We’ve been testing the Sense for just under a week, and there’s a lot more to it than just step counting.

It looks like a smartwatch

PHOTO: Jason Cipriani/CNN

The Sense looks a lot like the standard smartwatch or even the Versa series, but it’s slightly bigger. It has a metal ring that surrounds the AMOLED display. The display is bright, colorful and easy to view in low-light situations or in direct sunlight.

The ring around the display serves a functional purpose and will be used to take ECG readings once the software update is released that enables them. It’s also used to help the watch measure your stress level (more on that below).

Fitbit claims the Sense offers up to six days of battery life with the always-on component off, or around two days of battery with that feature on. We can confirm the always-on display does limit battery life to just a couple of days, but we haven’t had the watch long enough to test the full-length battery life with the display active only on demand, either by raising your wrist or by tapping on the display.

After four days of use with the always-on display off, the Sense currently has 20% battery left — so hitting six days will be close.

On the left side of the watch is a solid-state button that’s used to navigate the watch. A single press goes back to the home screen or wakes the watch, while a long-press or double-press will trigger an app shortcut of your choosing, or quickly view your favorite apps.

We struggled to consistently find the button and activate it every time. It’s almost too low on the watch’s housing for us to comfortably find it without having to press multiple times on the side of the watch. Toward the end of our testing, we started to more reliably locate it, but it’s definitely been an adjustment.

PHOTO: Jason Cipriani/CNN

The software experience on the Sense has been slightly tweaked as well. You can still swipe down on the watch face to see notifications, but now you can swipe up to see widgets that contain all sorts of information like weather or health stats. Swiping right on the display will show quick settings, like enabling do not disturb or sleep mode. Swiping left will show you all of your installed apps, including a watch face app that lets you quickly and easily switch faces without having to use the Android or iPhone app.

The Sense is available in carbon/graphite stainless steel or a lunar white/soft gold stainless steel color combination. We tested the carbon version, and it looks svelte on our wrist when paired with the Horween leather band.

But don’t call it a smartwatch

PHOTO: Jason Cipriani/CNN

Fitbit CEO James Park made it clear during Fitbit’s announcement event that the Sense is not a smartwatch — it’s a health watch. At first, we thought it was a tongue-in-cheek way of adding some flair to the Sense. But, after using it for a week, we understand what Park meant, and it’s not always for the better. We’ll explain.

The Fitbit Sense can record your blood oxygen levels, but only while you’re sleeping. You can’t manually take an Sp02 reading at any point — it’s all automatically done on your behalf each night after it detects you’ve fallen asleep. Fitbit tells me that this is done so the watch can take longer readings over the course of about five minutes, which should lead to more accurate results. (The Versa 3 takes the same approach to Sp02 readings, by the way.)

The thinking here is that with long-term readings, during a time when your body is likely to exhibit variations in oxygen levels, the Fitbit can help better detect a condition like sleep apnea.

We appreciate and even respect the thorough and cautious approach Fitbit is taking. The last thing any of us need is too much personal health data, which we can easily read too much into, or use it to incorrectly self-diagnose a condition. However, the process for getting that information into a readable and digestible format feels more like dealing with a medical device at the doctor’s office than it does a consumer device.

For example, in order for Sp02 to be captured while you sleep, you need to have the Fitbit’s Sp02 watch face as your main watch face when you go to bed. If you forget and fall asleep using another of your favorite faces, Sp02 just won’t be captured that night.

Then, when you wake in the morning, you have to leave it as the active watch face until the previous night’s data has been analyzed and synced to your Fitbit account. It’s a process that can take up to an hour, and it’s clunky.

On the second day of testing, we switched watch faces while waiting for the data to be processed and quickly learned that once you do that, you lose the previous night’s Sp02 info. On another occasion, we removed the Sense to get ready in the morning, and when we put it back on, there was an alert that it had restarted due to a crash and asked us to submit a bug report. Naturally, that also meant the Sp02 info from the night before was lost in the process.

There’s far too much thinking on the user’s part to view this specific health stat. The Sp02 readings should be a feature that “just works” and not one that you have a somewhat strict set of rules you need to follow. We shouldn’t have to remember to set the right watch face before going to bed, and then leave it on for a set amount of time in the morning before we can change to one of the more colorful faces.

Our core frustration with the Sense involves Sp02 readings and the multistep process it requires. The rest of the experience is exactly what we’d expect from Fitbit. Step counts are quick and easy to view, hourly reminders to get our steps in are never late and the new heart rate tech — PurePulse 2.0 — keeps tabs on your heart rate, showing dips when you’re relaxed and peaks when you’re stressed or active, and you’ll even see your average resting heart rate for each day.

PHOTO: Jason Cipriani/CNN

We received our Sense review sample on the same day as Apple’s Time Flies event, which is the first day of recordings in the screenshot above. The fact that our resting heart rate has slowly declined every day since is no coincidence (covering big launch events is stressful!).

Speaking of stress, the Sense can measure your electrodermal activity (EDA) response, which is a fancy term that shows your body’s response to stress. There’s an EDA app on the watch that you can use to take a quick two-minute reading — or, if you’re really feeling stressed and need to relax, let it guide you through a session that lasts anywhere from one to 60 minutes.

We used the quick session feature more than once, which consists of activating it and then placing your palm across the face of the Sense, making sure your hand is touching the metal band around the screen. The watch will vibrate when the session starts and then again two minutes later when the time is up. During that time, you’re supposed to stay still and remain quiet. If you lift your hand too early, the session pauses, the Sense vibrates and the timer is shown on the screen.

Once the timer ends, the watch will vibrate a few times, letting you know it’s time to lift your hand off the screen. The results will let you know how many EDA responses were detected, and ask you to log your current stress level. Our favorite part of this simple exercise, however, was the display of how much that two-minute session lowered our heart rate. At one point, we went from a heart rate of 101 to 71 just by taking two minutes to calm our mind.

Doing that a few times a day would go a long way in lowering our stress level, no doubt.

PHOTO: Jason Cipriani/CNN

Another new sensor on the Sense measures your skin temperature while you sleep and then provides a chart of how much it varies each night. You have to wear the Sense for three nights so it can gather a baseline before it will show you any measurements, but we’re still not really sure what any of it means. Last night, our skin temperature was 0.8 degrees above the baseline, but was that because it was just a hot night? Early signs of illness? Or was our arm under the covers for too long? Really hard to say.

Bottom line

If you want to know more about your body and your activity, and use that information to make informed decisions about your health, the Sense makes, well, sense. However, the lack of spot checks for Sp02, and the unnecessary steps you have to go through to even get a reading, is frustrating.

The Fitbit Sense collects, analyzes and displays a ton of information about you and your body. In some ways, it’s almost intimidating to have access to so much information, but on the other hand, it’s reassuring to know that over time you — and hopefully Fitbit — will learn what subtle changes to Sp02 or skin temperature mean for you. But after less than a week of use, it’s far too early for us to find meaning in some of the data. Outside of that lower resting heart rate, of course.

Those looking to dig into health data and keep the focus on that will be happy with the Sense, but if you want a smartwatch, the Apple Watch or Galaxy Watch 3 are a better fit.