Best Fitness Trackers of 2025

Back in the early days of running, we’d put on a pair of shoes and head out the door without a thought about choosing between the best fitness trackers or GPS devices. While those days were arguably simpler, we often ended up overtrained, injured, and without the data to make informed decisions about how to proceed with our training.

Now, with the advancement of fitness trackers — both as standalone devices and as part of GPS watches — we can track our every move, heartbeat, breath, and blood oxygen saturation level. While this may seem like an overwhelming amount of data, fitness trackers make it easy to get a more holistic view of how our bodies are responding to our training, provide clues if we’re about to get sick, and determine whether we need more training or need to step it back a notch. Fitness trackers measure metrics such as heart rate, heart rate variability, skin temperature, respiration, and blood oxygen saturation over time. They can analyze the data and create a visual representation to help us make decisions.

While most of the fitness trackers in this guide have GPS tracking functionality, most do not prioritize GPS capabilities. If you’re looking for a GPS tracking-specific device, be sure to check out our best running GPS watches guide.

To help you choose the best fitness tracker, we assessed various units on their battery life, display size, water resistance, GPS capability, extra features, ease of use, accuracy, and app connectivity. When it came to a GPS watch that did it all at a reasonable price point, we loved the Garmin vívoactive 5. For those who care more about fitness metrics and less about GPS tracking, the Fitbit Charge 6 is a great option.

For more background information on fitness trackers and what went into this guide’s testing, see our buying advice, testing methodology, and frequently asked questions below our top picks.

Best Fitness Trackers

• Best Fitness Tracker: Garmin vívoactive 5
• Best Fitness Tracker — Runner-Up: Coros Apex 2
• Best Fitness Tracker for Runners: Apple Watch Ultra 2
• Best Fitness Tracker for Women: Garmin Lily 2
• Best Ring Fitness Tracker: Oura Ring
• Best Budget Fitness Tracker: Fitbit Charge 6
• Best Smartphone Fitness Tracker: iPhone

Best Fitness Tracker: Garmin vívoactive 5 ($300)

Pros:

• Tracks all of the fitness stats we want
• Very lightweight and comfortable
• Good battery life

Cons:

• Not as intuitive to use as other trackers

The Garmin vívoactive 5 is a do-everything fitness tracker that is an excellent value. Despite its relatively low price, the watch is packed with Garmin’s most useful features in a sleek package. It tracks your sleep, giving you a sleep score and insights, as well as blood oxygen levels, and heart rate. Other metrics it measures include steps and respiration rate. It also features advanced metric calculations like fitness age, VO2 max, body battery, stress levels, and hydration.

It keeps you connected with smart notifications. We love the morning health report, the watch’s ability to give us weather updates, and the many activities it tracks. It has smart and handy features like Garmin Pay, the ability to find your watch or your phone, and its calculation of recovery time between activities.

It tracks many outdoor activities like running, swimming, and cycling, and it also excels at tracking indoor activities like yoga, Pilates, HIIT, and strength workouts. We also like that it has menstrual and pregnancy tracking for women and a wheelchair mode, so it works well for adaptive athletes.

We found that this watch had above-average battery life, lasting more than a week between charges. If used only as a smartwatch without GPS tracking, the battery will last 11 days. We also enjoyed the touchscreen, as it works better than most others we’ve tested. The 1.2-inch screen has an AMOLED display that is bright and easy to read.

The bottom line for this watch is if you’re looking for a fitness tracker at an excellent value that offers all of the features of Garmin’s higher-end watches, the vívoactive 5 has everything that you need and little you don’t.

Shop the Garmin vívoactive 5

Best Fitness Tracker — Runner-Up: Coros Apex 2 ($349)

Pros:

• Long battery life
• Abundant features

Cons:

• The scroll wheel is fidgety

For a long time, GPS watches and fitness trackers occupied two completely different worlds, and athletes had to wear two devices to gather their data. But now, watches like the Coros Apex 2 hold their own in tracking fitness metrics and can even outperform dedicated fitness trackers. There are several advantages to using your GPS watch as your fitness tracker, including only needing to own one device, having everything integrated into one platform, and getting consistent measurements whether you are at rest or active. We found the Apex 2 to be a great middle-of-the-road option that packed a lot of features into a relatively affordable package.

This watch can track nearly all of the metrics a fitness tracker can. In addition to constant heart rate monitoring, it also can measure your heart rate variability (HRV). This measure has become increasingly popular as a way to assess recovery. Essentially, it measures the differences in the time between heartbeats. You can dive deeply into HRV at What the Heck is Heart Rate Variability?

For a long time, GPS watches didn’t have an accurate enough optical heart rate sensor to provide this measurement, but advances in the watches now mean that it’s fairly standard. To optimize its accuracy, the Apex 2 uses a five-LED light system and four photodetectors in its new heart rate monitoring system.

This watch also measures various other metrics, including sleep time and quality, and it can differentiate between deep, light, and REM sleep. You can also take blood oxygen saturation readings with it to see how you are acclimating to high elevations. All this data allows the watch to estimate your recovery times, fitness level, and more.

It’s easy to set up the Coros app on any smartphone, and the watch connects to it seamlessly to download all of your metrics. The app makes it easy to visualize all the data, and you can track your metrics over time and see real-time measurements. And that’s just the fitness tracking side.

This is also a great GPS watch. Like all Coros products, it has a large battery and provides 40 hours of GPS tracking time. If you’re not using the GPS feature, the battery will last 14 days. Charging the watch from zero to full takes less than two hours. The watch uses five satellite systems for outstanding accuracy.

One thing we appreciated about this watch was its size — it was smaller than many other GPS watches. It comes with a 1.2-inch sapphire screen and titanium bezel, and we found it plenty durable. It measures all the standards for a GPS watch, including altitude and barometric pressure, and has a built-in compass.

While this watch costs more than a standalone fitness tracker, it’s quite affordable for a GPS watch. If you want a device that can track all of your important health metrics, as well as your run, and download it to a third-party app like Strava, this is a great option. You can read more about other GPS watches that also have fitness tracking in our best GPS running watches guide.

Shop the Coros Apex 2

Best Fitness Tracker for Runners: Apple Watch Ultra 2 ($799)

Pros:

• Excellent fitness tracking
• Good GPS
• Decent heart rate monitoring
• Excellent integration with iPhone and apps

Cons:

• Expensive
• It only connects with an iPhone

Two things kept us from naming the Apple Watch Ultra 2 our best overall fitness tracker. First, the price — it’s more than double the cost of the Coros Apex 2 and the Garmin vívoactive 5 and much more expensive than your average fitness tracker. Second, it only integrates with other Apple products. But aside from those two major drawbacks, there are many reasons we named it the best smartwatch in our best GPS running watches guide and are also including it in this guide.

This new version of the watch only has a few upgrades from the previous — a brighter screen, a faster processor, and more memory. But as far as features go, the two watches are essentially identical. If you want to learn more about the GPS-specific features of this watch, you can read our in-depth review of the Apple Watch Ultra.

When it comes to tracking fitness, there are a few features that set this watch apart from the rest. From a health standpoint, one of the biggest advantages of this watch is its ability to make EKG measurements and detect atrial fibrillation. If you suffer from atrial fibrillation, this watch can alert you if it detects an irregular heartbeat. You’ll be able to check the EKG graph and take appropriate action.

The watch will also alert you if it senses an unusually high or low heart rate. The watch also collects skin temperature data, a relatively rare feature in the GPS watch world. This can help women with cycle tracking and help you spot abnormalities in how your body reacts to certain situations.

The watch also has all the other standard features found in fitness trackers, including counting how many steps you take daily and tracking sleep. You can use the watch to set and measure fitness goals related to movement, exercise, and standing time. The watch tracks your daily progress and visualizes it with a set of rings to try to complete each day. You can get a detailed update on your day by tapping the appropriate ring, and you can adjust and customize your goals.

As with all Apple products, this watch is sleek, eye-catching, intuitive, and easy to use. It outperforms everything else if you’re looking for an exceptional user experience. With its super-bright screen and easy-to-navigate menus, it’s far easier to learn to operate than many other GPS watches with fitness tracking features. The 49-millimeter titanium case is durable.

The battery will last 36 hours of non-GPS use, which is quite short compared to other GPS watches. Luckily, it recharges quickly. We also like the SOS emergency feature. The main tester of this watch took a tumble during a gravel bike ride in the Santa Monica Mountains, and the SOS emergency feature immediately asked if they needed an emergency call. The tester declined, and it followed up by asking if there was a fall and if the tester was okay.

Despite its drawbacks, we think the Apple Watch Ultra 2 is probably the most complete, accurate, and user-friendly fitness tracker we tested. We just wish it wasn’t $800 and the battery lasted a tad longer.

We will say that the updates between the original Apple Watch Ultra and this one are quite incremental. With a faster processor, a brighter screen, and twice the memory, it’s Apple’s most advanced watch. But if you’re concerned about the price, you can get the original without sacrificing features.

Shop the Apple Watch Ultra 2

Best Fitness Tracker for Women: Garmin Lily 2 ($250)

Pros:

• Very lightweight and comfortable
• Stylish enough to wear to work
• Excellent value
• Multiple band options

Cons:

• Not great battery life

All of the fitness trackers on this list will work for women, but the Garmin Lily 2 is designed specifically for them. Overall, we love this watch because, like the Garmin vívoactive 5 above, it offers all of Garmin’s essential fitness tracking features, as well as some higher-end features, at an excellent price. We love this specific version because of its stylish look, which will work for nicer events as well as everyday wear. Essentially, if you’re looking for a fitness tracker that doesn’t look like a fitness tracker, this is a smart option.

The watch monitors, tracks, and calculates Garmin’s typical fitness tracking measurements like the body battery, your sleep score, and indoor and outdoor activity tracking for running, cycling, yoga, strength training, and even dance.

We like that it has some bonus features like Garmin Pay, safety and incident tracking, calendar view, and smart notifications. Plus, it tracks health and fitness-specific measurements like respiratory rates, resting heart rate, blood oxygen levels, menstrual cycles, and pregnancy. We also like that it includes Garmin’s meditation and breathing exercises.

The battery life isn’t the best, as we could only get a few days at a time between charges, and some users reported the leather band fraying a bit after extended use. Garmin does give you multiple band options, so you can choose one that works for you.

Overall, we see this fitness tracking watch as ideal for someone looking for an option that will track activities, health, and fitness features while not looking like a more rugged GPS watch.

Shop the Garmin Lily 2

Best Ring Fitness Tracker: Oura Ring ($249)

Pros:

• Excellent at sleep tracking
• Good for anyone not wanting a watch

Cons:

• Very short battery life

For those looking for a fitness tracker that is less obtrusive than a watch, we love the Oura Ring. There are two main reasons to get the Oura Ring versus a watch. First, there was no better device at tracking sleep, and sleeping in a ring is generally more comfortable for folks than a bulky watch. Second, if you want to track your fitness but don’t like watches or don’t want to wear them to work, and ring is much more subtle while still collecting all of the health data. Put simply: If you prefer to wear rings over watches, you can still track your fitness and health with the Oura Ring.

We found that the Oura Ring did an excellent job tracking heart rate variability and suggesting rest days. Heart rate variability can be affected by anxiety or other stresses in your life outside of regular training, and the ring seemed to do a great job at detecting when our overall stress load was high and we needed a rest. We also love that Oura partnered with Strava, and the two can now share data.

Another population that should seriously consider the Oura Ring versus the other fitness trackers in this guide are pregnancy-planning women. The Oura Ring’s ability to track body temperature readings is top-notch. Skin temperature readings paired with other fertility indicators can help with pregnancy planning. Oura also has a partnership with Natural Cycles, the birth control app.

Our main nitpick with the Oura Ring is its short battery life. We were not able to get more than a couple of days of use between charges.

Shop the Oura Ring

Best Budget Fitness Tracker: Fitbit Charge 6 ($160)

Pros:

• Many band options
• Excellent value
• Connects to exercise machines for real-time heart rate on display

Cons:

• Not great for GPS

If you don’t need a GPS watch but are still looking to track health metrics, the Fitbit Charge 6 is an option at a much lower price point. While the device has GPS capabilities, we found them less accurate, and frankly, they’re not the central focus. But when it comes to fitness tracking, this small wrist-worn unit can give you all the information you need. It’ll track your daily health metrics and activities to give you a holistic view of your body.

As its main features, this device will measure your cardio fitness level, number of daily steps, sleep, blood oxygen level, and stress level. Like the Apple Watch Ultra 2 reviewed above, it also tracks skin temperature, which can be especially useful for women tracking their cycle. The company claims this model has the most accurate heart rate monitor of their units.

While wrist-worn heart rate monitors are prone to erroneous points during running due to arm swing and will never be as precise as chest-worn EKG heart rate monitors, we found this one to do a decently good job. You can learn more about chest-strap heart rate monitors and other options in our best heart rate monitors for running guide.

This device can also alert you to irregular heart rhythms caused by atrial fibrillation, an increasingly common feature in fitness trackers but not yet included in many GPS watches. The Fitbit Charge 6 uses a variety of measurements to give you a Daily Readiness Score. You can use this number to inform your decisions on how to proceed with your training and help you understand when to dial it back and when you have the energy to push.

The battery of this outperforms the Apple Watch Ultra 2, and while its battery life is not as long as standard GPS watches, it’s still plenty for most people. It’ll continually monitor your health for a week without a charge.

We appreciated that this watch has a SmartTrack feature that starts measuring an activity, even if we forgot to start the device ourselves. We also liked the look of the device. It’s far more compact and discrete than any GPS watch, and it’s easy to forget you’re wearing it. The watch face is flat and small, and there are several band options to choose from.

Shop the Fitbit Charge 6

Best Smartphone Fitness Tracker: iPhone

Pros:

• You might already have one
• It’s easy to set goals and prompt suggestions to reach those goals
• It’s easy to track trends and connect to other third-party apps

Cons:

• iPhones are expensive
• There’s no way to track activities

You know that iPhone you might already be glued to? It is also already a solid fitness tracker. Apple’s Fitness and Health apps come built-in with each iPhone, meaning you can begin tracking your fitness immediately upon purchase of an iPhone. And combining both apps gives you an extremely comprehensive look at your fitness data and trends.

Like the Apple Watch Ultra 2 above, the app’s base is in the rings. You get a red Move, green Exercise, and blue Stand ring that helps you reach the predetermined goals that you set. For example, our main tester has a daily Move goal of 850 calories, an Exercise goal of 60 minutes, and a Stand goal of six hours. The rings move each day as you complete activities to close each ring. The app’s base also tracks total steps and distance traveled each day.

The Fitness app also tracks your workout history, connecting to third-party apps like Peloton or Strava. It gives weekly video fitness tips, fitness trends, and move awards. Our one qualm with the Fitness app on the iPhone is it doesn’t track actual activities. Meaning if you go for a run, you’ll need to track it through a connected third-party app like Strava. It’s not a huge deal; it’s just kind of an annoyance.

Apple’s Health app is robust. It tracks trends like averages for the number of flights climbed, steps, walking and running distances, standing hours, resting heart rate, exercise minutes, and others. It tracks your workout history, average and daily calories burned, post-workout heart rates, and other categories.

The Health app also goes beyond physical activity and allows users to track moods and emotions, and take mental health questionnaires. You can also track any prescription medications you take and learn about more medically focused measurements like blood oxygen levels.

If you already own an iPhone, you already have a fitness tracker. Yes, there are some cons, like the upfront cost of an iPhone and the fact that you’ll have to carry your phone on runs to track them (instead of wearing a watch or tracker on your wrist), but an iPhone tracks everything, is user-friendly, and easily provides health and fitness trends and data.

Shop the iPhone

Comparing the Best Fitness Trackers

FITNESS TRACKER	PRICE	BATTERY LIFE	SIZE	GPS
Coros Apex 2	$349	14 days	1.2 inches (display)	Yes
Garmin vívoactive 5	$300	11 days	1.2 inches (display)	Yes
Apple Watch Ultra 2	$799	1.5 days	1.9 inches (display)	Yes
Garmin Lily 2	$250	5 days	1 inch (display)	Yes
Oura Ring	$349	7 days	0.3 inches (width)	No
Fitbit Charge 6	$160	7 days	1.45 inches (display)	Yes
iPhone	$550	1.5 days	6.1 inches (display)	Yes

 

How to Choose a Fitness Tracker

Battery Life

The battery life between fitness trackers can vary drastically, ranging from the 36-hour lifespan of the Apple Watch Ultra 2 to GPS watches that will last for weeks without a charge. With extended battery life comes a bulkier watch, so if you want something sleek and small, the biggest thing you will have to sacrifice is battery life.

A bigger battery will also cost more money. This is where your intended use is important. Are you someone who wants a device that will gather your fitness data during an ultra where you’ll need enough battery to power GPS tracking as well? Or do you normally use your device for shorter activities when you can charge it frequently?

The Coros Apex 2, along with Coros watches in general, has a long battery life that will last through nearly any ultramarathon. It will also measure health metrics for 13 days without GPS use. If you’re not concerned about battery life or know you’ll be able to charge your device daily or between efforts, you might not care to spend the money on a bigger battery.

Activity Tracking

If you love a device that can gather fitness and GPS data from your runs, you’ll likely want a GPS watch instead of a dedicated fitness tracker. All of the watches included here can track a variety of different activities, some of them more accurately than others.

The Apple Watch Ultra 2 made a concerted effort to nail down tracking the swimming activity and many other activities. The Coros Apex 2 tracks an impressive array of activities on its interface, including sports like snowboarding, windsurfing, and mountain climbing. And the Fitbit Charge 6 tracks around 40 activities.

We found the GPS accuracy of the Apple Watch Ultra 2 and the Coros Apex 2 to be pretty similar. If you want to use your device for navigation while on a run, you’ll want to go with one of these options.

GPS

GPS (Global Positioning System) relies on a system of satellites to track your position and calculate your speed and the distance you’ve traveled using a process called triangulation. Do you need it in your fitness tracker? Maybe. If you’re trying to keep track of mileage, elevation, or speed, or you’re training for a specific running goal, having a device that offers both GPS and fitness tracking makes it easy to keep all of your data in one spot and consistent. Plus, you only have to buy, carry, and charge one device.

That said, some people have no interest in running with a GPS watch but still want to keep track of their health metrics. For these people, buying a dedicated fitness tracker can save them a lot of money over a GPS watch. A device like the Fitbit Charge 6 is primarily designed to be a fitness tracker but also has GPS capabilities. Other devices on the market, like the Oura Ring, have no GPS features and focus purely on fitness tracking.

Heart Rate Sensors and Measuring

Heart rate measurement is universal throughout all fitness trackers, whether they have GPS capabilities or not. It’s one of the primary metrics measured by athletes since early times when we’d place fingers on our neck or wrist after a sprint to attempt to measure the intensity of an effort.

Luckily, heart rate measurement has come a long way since those early days. An EKG chest strap linked to a device is the most accurate way to measure heart rate during a run. Optical measurement devices on the wrist tend to be less accurate, especially at high heart rates, though new technology has improved this measurement significantly. You can dive deeper into how these devices work and their accuracy in our best heart rate monitors guide.

Heart rate measurements are useful for a variety of reasons. The most obvious heart rate measurement is to track your exertion level during exercise. It remains the most accessible and accurate way to tell how hard you work on any run. Resting heart rate, which can be calculated both from your heart rate while you’re not exercising during the day or while asleep, can give you a gauge of your fitness level.

While the absolute number varies from individual to individual, a lower resting heart rate generally correlates with a higher fitness level. An elevated resting heart rate can indicate an infection or overtraining.

Lastly, many fitness trackers have the sensitivity to detect abnormal heart rhythms, such as those caused by atrial fibrillation. The Apple Watch Ultra 2 and the Fitbit Charge 6 can quickly alert you to this dangerous heart condition so you can take action. However, these are not medical devices and shouldn’t be the only instruments used to measure and track irregular heartbeats.

Water Resistance

Runners inevitably get caught out in the rain, want to jump in a lake at the end of a run, or partake in water-based cross-training activities. Fitness trackers need to withstand moisture so we can wear them in all conditions. The three watches in this guide are water-resistant to depths of 50 meters. The Apple Watch Ultra 2 contains new algorithms for measuring swimming activities in a pool and open water. It can count laps, track pace, and estimate calorie burn in the pool or surf.

Bluetooth Compatibility and Apps

Most wearable fitness trackers use Bluetooth to transfer data to a smartphone. Each device has its own app that can visualize the data and summarize your activities, and most can also connect to third-party apps like Strava.

Many fitness trackers and GPS watches can also store music and connect to a pair of headphones so that you can listen to music or a podcast on your run without carrying your phone. While the Apple Watch Ultra 2 acts the most like a phone without being a phone in terms of functionality, the Coros Apex 2 can also store music for offline listening.

All three devices can easily connect to third-party apps for more data analysis and tracking. The Apple Watch Ultra 2 interacts with several Apple apps, like Fitness and Workout, to help users track daily and ongoing progress. Coros and Fitbit also offer a list of supported third-party apps that can help you track and plan your workouts on your fitness journey.

Ease of Use

It is important to consider the fitness tracker’s ease of use. Is the data easily accessible? Is it presented in a manner that makes it easy to understand and tracks ongoing progress? How about the device’s versatility? Is it easy to set up and use on the go?

If you’re an Apple user, you probably already appreciate the ease of use of the brand’s products, and the Apple Watch Ultra 2 puts a premium on the user experience. It easily pairs with an iPhone and other Apple products and is intuitive to use. GPS watches, including the Coros Apex 2, tend to have a bit of a learning curve to fully utilize all of their features.

That said, it’s generally pretty easy to get started with the basics, and the watch will start tracking fitness metrics as soon as you set it up and wear it, allowing you to take a deeper dive into the features and data over time. The Coros app is fairly simple and straightforward to use.

Smartphones as Fitness Trackers

If there’s one thing most of us don’t leave home without, it’s our smartphones. If you want to keep track of your basic fitness metrics, such as the number of steps you take each day, your smartphone will probably be plenty. The iPhone can provide a large number of health metrics and provide you with daily goals to strive toward. Phones feature an accelerometer that can keep track of your movement each day.

Using an app like Strava can also provide GPS tracking with your phone, though this will wear through your battery fairly quickly. You can also use fitness apps on your smartphone to connect to heart rate monitors to keep track of your effort level during exercise. If you’re looking for simplicity, you probably already own a phone that will calculate basic fitness metrics.

Why You Should Trust Us

There are endless options for fitness trackers that will measure everything from the number of steps you take per day to calculating your body battery and stress levels using a variety of metrics, including respiration, heart rate, heart rate variability, and skin temperature. As runners, we focused our research on devices that made sense for our specific needs — watches with GPS capabilities to track mileage, pace, and other run metrics.

We researched the fitness-tracking capabilities of the devices our team members have been using for years. We tested several over many months to delve into the types and quality of data they provided.

We tested the devices throughout the day and night. We wore them while running, sleeping, making dinner, working, and doing all the other countless activities that make up a day. We also took them out on hikes, bike rides, paddle boards, and skiing. We also took them into the weight room. Our goal was to test the capabilities of the trackers both while we were at rest and at maximum exertion levels.

We evaluated the devices based on their accuracy, battery life, price, comfort, appearance, and breadth of features. We also considered their ease of use because we know no one wants to get frustrated with trying to figure out how to make a piece of technology work for them.

Frequently Asked Questions About Fitness Trackers

What’s the difference between a fitness tracker and a GPS watch?

At a fundamental level, a fitness tracker measures various health metrics, and a GPS watch tracks your location. But in many cases, including many of the devices in this guide, all these features are included in a single device. A GPS watch will measure health metrics, and a fitness tracker will also have GPS capabilities.

There are fitness tracking devices on the market without GPS capabilities, like the Oura Ring, and they tend to be smaller and more discrete to wear. It’s unclear whether these devices do a better or worse job than the measurements made by a GPS-focused watch, like the Coros Apex 2. In our testing, we found that GPS-watch health metrics lined up reasonably accurately with our self-assessments of our health and energy levels.

The benefit of using a device that tracks fitness metrics and has GPS capabilities is that it keeps all your data in one place. This ensures consistency, both in the moment and over time. With a GPS watch, you can correlate an increase in heart rate with a specific part of your run or see how you recover while running on easier terrain. Having a dual-function device also means you only have to wear one device for all of your needs.

How accurate are fitness trackers?

While most devices measure similar metrics, including number of steps taken, respiration, heart rate, heart rate variability, and blood oxygen saturation level — and do it fairly accurately — they all use different algorithms to calculate and visualize data such as your energy level, body battery, stress level, and sleep quality.

Different devices worn at the same time can produce different analyses of the same data collected. Some device algorithms focus on specific types of running and are great for calculating fitness metrics if you’re in the middle of training for a marathon but will falter if you’re on a strenuous backpacking trip. It’s important to remember that metrics such as body battery or stress level are calculations that may not take into account the specifics of your situation.

An EKG heart rate strap will always be more accurate than a wrist-worn optical device when measuring heart rate. The movement of a watch on the wrist can introduce errors in the data, especially at higher heart rates when you’re running fast and moving your arms a lot. If you want the most accurate heart rate measurement, it’s worth looking at our best heart rate monitors for running guide. This is one measurement that device technology has really nailed down.

The GPS on fitness trackers is generally accurate to within 10 feet of your actual location — unless you’re somewhere with a lot of trees, mountains, or heavy cloud cover. Some high-end watches use a five-satellite system to locate themselves instead of the traditional three-satellite system, which makes them more accurate in areas where a watch could have a hard time locating a satellite.

We found little difference between the GPS accuracy of the Coros Apex 2 and the Apple Watch Ultra 2. You can read more about GPS accuracy and functionality in our best GPS running watches guide.

What are the most important fitness metrics to track?

Tracking fitness metrics can be a deep rabbit hole to dive down. The most basic metric most fitness trackers measure is steps taken each day. Most smartphones also track this, assuming that you carry your phone everywhere you go.

Over the years, several successful initiatives have challenged people to take a certain number of daily steps to improve their overall health. If you’re looking for a more in-depth analysis of your daily health, a fitness tracker can measure continuous heart rate, respiration, blood oxygen saturation level, heart rate variability, and body temperature.

From these measurements, the devices can calculate your overall fitness, stress levels, sleep quality and time in various sleep zones, energy levels, and more. It’s important to remember that some metrics, such as heart rate, are measured directly by the device, and others are calculated and can vary between devices.

Wearing a device consistently is the best way to build up a data set of your specific fitness metrics to allow you to see trends over time. For example, resting heart rate, which is measured as your average heart rate while you sleep, can decrease as fitness increases, but it can also spike while you’re overtraining or about to get sick.

Understanding long-term trends in your fitness metrics can help you make training decisions and determine whether you’re overtraining or ready for more intense training.

Some devices, including the Apple Watch Ultra 2 and the Fitbit Charge 6, have alarms that can alert you to abnormal heart rhythms. If you have issues with atrial fibrillation, wearing one of these devices can alert you to an episode and give you extra time to seek help.

How long does a fitness tracker last?

The lifespan of these devices is generally longer than that of the technology included in them, and most people will want to replace a device for an updated feature before it actually stops working. New updates to software and hardware are constantly extending the lifespan of fitness trackers, and while many companies release an updated version of their device each year, most people can use one for years. Many members of the iRunFar team have been wearing the same GPS watches, including the Coros Apex 2, for years without issue.

Call for Comments

• Do you have a favorite fitness tracker that we don’t have here?
• Have you found it beneficial to have a fitness tracker in your life?