The Fitbit Charge 4 ($150 at Best Buy) has everything you need in a fitness tracker for under $200. It finally includes built-in GPS to track outdoor workouts independently, it has better training tools for athletes, and it fits most of the same smartwatch features into a slimmer package than the more expensive Fitbit Versa ($189 at Amazon). It's my favorite Fitbit yet. If you're looking for a fitness tracker than behaves a lot like a smartwatch without the extra bulk, the Fitbit Charge 4 might be the perfect fit. 

Added features without the added bulk 

There are plenty of great wearables for athletes, like the Garmin Forerunner 945 and Suunto 3, that have way more fitness chops than the Charge 4, but they're not the most fashionable. The $150 Charge 4 (£130, AU$230) is a tracker I will happily wear 24/7 thanks to its sleek, understated design. If you're familiar with the Charge 3 ($116 at Amazon), the new version doesn't look much different -- it's just the tiniest bit bulkier on your wrist. 

The screen can only display in black and white, but I like that it's nearly half the size of a traditional smartwatch, such as the Apple Watch ($399 at Apple), and it also does away with physical buttons. Instead, you control the Charge 4 with a combination of the touchscreen and by pressing the left side of the tracker to navigate settings. The touchscreen isn't as responsive and it takes a few seconds to light up when you raise your arm to wake the screen, but I eventually got where I wanted to go. The only time the lag really bothered me was while I was running and wanted to quickly glance at my stats without taking my eyes off the road. Like the Charge 3, it's also hard to see the screen in direct sunlight. 

The regular Charge 4 comes in three different colors with silicone sports bands, but the Special Edition, or SE, version that I tested out also comes with a woven band option for $20 more. Straps are easy to swap out (unlike the Versa 2 ($200 at Best Buy), which has tricky toggles) and if you're upgrading from the Charge 3 you'll be able to use those bands on the newer tracker. There are also a bunch of third-party strap options available to customize your look. 

The Charge 4 is comfortable to wear throughout the day and doesn't dig into my skin when I tighten it up during a run. You can also wear it to bed. Like other Fitbits, it also tracks your sleep. I won't go as far as to say that it's comfortable to wear in bed, but at least I didn't want to rip it off in the middle of the night like other trackers. 

The Charge 4 pushed me to run faster

As a basic fitness tracker, the previous Charge models already checked most of the boxes: measuring steps, calories, floors climbed, heart rate and distance (using your phone's GPS). But that wasn't enough for more serious runners like me. I'm by no means an elite athlete, but I do run on a regular basis, so having a built-in GPS is high on my wish list. The GPS allows the Charge 4 to map your route during an outdoor walk, run, bike ride or hike without having to rely on your phone. 

I've gone on a few runs and the Charge 4 has given consistent distance readings on the same route with and without my phone. You can also see a heat map of your route on the Fitbit app, which also indicates the intensity at which you were running based on your heart rate. 

The only other Fitbit device that offers built-in GPS feature is the Ionic ($220 at Amazon) watch, but it's now over two years old and I found it too big and bulky to wear on a regular basis.

The Charge 4 tracks over 20 different activities, from cycling to yoga. It's also water resistant up to 50 meters like the Charge 3, so you can use it for swimming. You can program up to six exercise shortcuts on the Charge 4, but you do have to choose them and sync from the phone app. You can also set it to track your runs automatically, and set goals for things like pace, distance or calories burned before you start each activity. 

GPS is not the only tool for athletes. The Charge 4 has added a new metric called Active Zone Minutes, which uses your heart rate zones to determine the intensity of your workout. The goal is to have 150 active minutes logged by the end of each week, but you can increase or decrease the target based on your fitness level. 

A few years ago, Fitbit started breaking out heart rate data into training zones for each activity, based on age and weight. After a workout you can log into the mobile app and see how long you were in fat burn, cardio or peak. The Charge 4 adds real-time heart rate zone notifications so you can take action during your workout. 

I had to push myself much harder than usual to get my peak heart rate alert to pop up on the screen (you also get a buzz on your wrist when you reach each zone). I realized I'd been overestimating my effort and it was helpful to have the Charge nudging me to get out of my comfort zone. I can see this being a good training tool if you're looking to break your personal record in a race.

Battery life takes a hit

The only downside about having GPS on the Charge is that it'll gobble up your battery a lot faster than on the Charge 3. Fitbit says the Charge 4 can last up to seven days on a charge, but I barely made it to day four before having to plug it in.

I didn't mind having to recharge after four days, but if you're looking to get the most out of your battery life (and are planning to use it at night) I would recommend turning off the GPS when it's not in use. You'll just have to remember to do this after your workout. You can do this from the exercise shortcuts on the Charge. Just swipe up from an activity that uses GPS, like running or cycling, and toggle it off. 

Sleep tracking has some serious benefits 

I've never gotten much out of tracking my sleep in the past. With a 6-month-old baby and a toddler waking me up at odd hours of the night I was scared to even see my stats the next morning, let alone get graded on my sleep. Each morning, the Fitbit app gives you a Sleep Score based on everything from sleep duration to sleep stages, heart rate and variations in blood oxygen levels, aka SPO2. 

After a few nights of testing, it's actually provided some useful data about my sleep habits. For starters, I've gotten a passing grade (above a 60) every single night, despite waking up to nurse my little one. The app told me it's normal to spend up to 45 minutes awake each night, which was comforting. It also gives you advice on how to improve your score, like keeping your bedtime consistent, regardless of how late (or early) it is. 

Everyone can see basic information in the app, like how much sleep you get and its quality, but Fitbit Premium subscribers get access to heart rate and blood oxygen data. I didn't see anything out of the ordinary in my chart, but I can see this feature being extremely helpful for people who suspect they might have a more serious sleep-related condition like sleep apnea. In that case it might be worth the extra $9.99 (£8.99, AU$15.49) a month for a premium account. 

There is one foreseeable downside: With all this sleep data I worry that I might become dependent on the Sleep Score to feel energized during the day. That is, a low Sleep Score may subconsciously make me feel tired, even though I felt like I got a good night's rest. 

More than just a fitness tracker

The Charge 4 goes beyond health and fitness tracking with a few smart features up its sleeve. It mirrors every notification you can get on your phone whether you have an iPhone ($699 at Apple) or an Android phone, but only Android users will be able to reply to messages with preprogrammed quick replies. 

You still can't store music onboard to take with you on a run, but if you're a Spotify Premium subscriber, you will be able to use the Charge 4 as a basic wrist remote to pause and skip tracks. There's no volume control though. 

It now also includes a new agenda app along with the existing timer, alarm and weather apps. 

You'll be able to set up Fitbit Pay on your wrist and use the Charge 4 on any tap-to-pay payment terminal as the tracker now comes with built-in NFC (previously, you had to buy the special edition Charge to get Fitbit Pay). Sadly it still doesn't have as many bank partners as Google or Apple Pay and was not compatible with my primary bank (US Bank), so I couldn't test it out. I'm also quarantined at home, so most of my payments are made online anyways, not at brick-and-mortar stores. 

Everything you need in a tiny package

The Charge 4 does a lot considering it's essentially a fitness tracker. But you don't end up saving that much compared to a smartwatch like Fitbit's own Versa 2 (the regular Charge 4 is $50 less than the Versa 2, which only has connected GPS).

So the price alone is not reason enough to choose the Charge 4. For me, it's about getting everything Fitbit offers, including GPS, in a slimmer package than the Versa 2. The Charge 4 is my favorite Fitbit to date.  

First published on May 18.