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We spent six weeks running, walking, swimming, cycling, sleeping and, in short, living with 13 fitness trackers day and night to assess their accuracy, ease of use and comfort. Although no tracker perfectly recorded every metric it attempted to, we are confident that the easy-to-use and long-lasting Fitbit Charge 3 is the best activity monitor to help people achieve their health goals.
our pick
Of all the trackers we tested, the Fitbit Charge 3 is the simplest to use and among the most accurate for measuring steps and heart rate – although accuracy isn’t everything. It reliably senses, correctly identifies and begins to record your workouts – running, walking, biking – after about 10 minutes of movement. The combination of a touchscreen display, an inductive “button” on the side, and clearly labelled icons make the menus easy to navigate. The user-friendly app links you to a robust network of other Fitbit wearers, who can help motivate you. You can use that app as well to choose which smartphone notifications to receive, so only the ones you want will buzz on your wrist. In addition, the Charge 3 tracks how long and how well you sleep at night, and it can even detect naps, unlike many of its competitors. Its above-average battery life means you’ll be able to wear it for longer at a stretch, too.
Battery life: up to seven days
Sleep tracking: yes, including naps
Waterproof: yes, 50 metres
Heart-rate monitor: yes
GPS: yes, when connected to a phone
runner-up
The Garmin Vívosmart 4 is remarkably small – as small as the devices we tested that lack displays – yet it makes good use of its itty-bitty touchscreen. (For instance, smartphone notifications scroll horizontally across the face like a ticker tape.) In our testing, the Vívosmart 4 measured step count and heart rate as accurately as the Charge 3 did. Unfortunately, it didn’t detect activities as effectively, the menus in its app can be confusing to navigate, and the touchscreen doesn’t work in the pool. Also, the Garmin social network for fitness trackers is smaller than Fitbit’s. But if the Charge 3 is out of stock, or if you want the smallest, sleekest activity monitor that still offers a display screen, the Vívosmart is a good option – as long as you aren’t a big swimmer.
Battery life: up to seven days
Sleep tracking: yes, but not including naps
Waterproof: yes, 50 metres
Heart-rate monitor: yes
GPS: no
budget pick
Like the Charge 3, the Fitbit Flex 2 tracks your movement automatically, and it does a pretty good job of recognising and measuring activities. It has no display screen, though, so if you want to get any information about those activities, you have to go to Fitbit’s app or website (where you also get access to the vibrant Fitbit social network). The Flex 2 can tell you, roughly, how close you are to your step goal and remind you to move if you’ve been sitting too long, but you have to learn how to read its code of blinking LEDs and vibrations. It lacks a heart-rate monitor, which means that the sleep data you get is rudimentary – just how long you slept, not how deeply. The Flex 2 has the slimmest wristband of any tracker we tested, the battery life, though, is shorter as well.
Battery life: up to five days
Sleep tracking: yes, including naps
Waterproof: yes, 50 metres
Heart-rate monitor: no
GPS: no
also great
If you’re an especially active type and you want to keep in-depth records of all your workouts, the big, watch-like Garmin Vívoactive 3 could be for you. (However, if keeping a log of your miles and having physical buttons for use during workouts are top priorities, consider a GPS running watch instead.) Its heart-rate monitoring was the most accurate of any we tested, and the same was true of its all-day step count. In addition to having 20 predesigned exercise modes, the Vívoactive 3 lets you create your own, and it also has onboard GPS for mapping outdoor walks, runs and bike rides. However, it has the same flaws as other Garmin models: it doesn’t detect activities well, its app isn’t easy to use and its sleep tracking isn’t particularly accurate. The Vívoactive 3’s watch faces, menus and workout data screens are more customisable than those on any other device we tested. And the large, colour touchscreen is responsive, even in the water, and never dims completely – although battery life suffers because of this.
Battery life: up to seven days (13 hours in GPS mode)
Sleep tracking: yes, but not including naps
Waterproof: yes, 50 metres
Heart-rate monitor: yes, also compatible with chest strap
GPS: yes
Who this is for
The lines that separate GPS running watches and smartwatches from dedicated fitness trackers are blurrier than ever. GPS watches can now track your activities all day and your sleep at night. Smartwatches can now capture your movement with auto-activity detection and built-in GPS. We still see a place for fitness trackers, though. They’re much less bulky to wear than GPS running watches, and they usually cost a lot less, too. They can run for up to a week between charges, unlike smartwatches, which you generally need to charge daily. And the latest generation of trackers go well beyond just counting steps and recording workouts: they include more smartwatch features than before – from interactive notifications to third-party apps – and additional sensors to provide more granular detail on movement and sleep.
The trackers we looked at are for people who want a better idea of how often they move, how much they move, and the ways that they move throughout their days and nights. They’re for people who want to set goals to increase daily movement, exercise more often and improve sleep habits. They (and their apps) are also for people who want a place to log their diets, hydration and even menstrual cycles, to gain a broader picture of their health. The differences among these trackers are principally the number of sensors – and therefore features – they offer and, most important, how easy they are to use.
We want to stress that these trackers are not a replacement for a medical device. Consult your doctor before beginning any new exercise routine. If you suspect you may have a sleep condition, see your doctor. And if a high heart rate is a health concern for you, don’t rely on an activity tracker to help manage your condition.
How we picked and tested
To come up with our testing pool, I made a list of all the activity trackers I could find for sale in the US – new models as well as those from previous generations that are still available. Of the 28 trackers on that list, I eliminated those that I knew, from previous versions of this guide, wouldn’t do well in our tests. I also weeded out any with consistently poor reviews from owners or from other editorial outlets. Most of the 13 trackers remaining on my list were wrist wearables, mainly from the biggest players, Fitbit and Garmin. (RIP, Jawbone.) But not everyone wants to wear a bracelet – and the old, clip-style trackers have almost disappeared – so I also called in a few new non-wrist options.
I put these 13 trackers through their paces, looking to answer the following questions:
How easy is it to use and live with? Because these are devices you’re meant to wear all day, every day, I put a lot of emphasis on comfort, wearability and user-friendliness – of both the device and its companion app. In living with each one, I considered:
- Is the device comfortable to wear all day and to sleep with all night?
- Are the device’s menus easy to navigate? Can you decide which workout types and data (step count, calories burned, distance travelled) you want to see?
- Is the app inviting to use?
- Do any smartwatch features work well?
- Does the battery last as long as promised?
- Is it waterproof or at least water resistant, or do you have to take it off before showering or swimming?
How well does it track activities? To gauge how accurately the trackers recorded all-day step count, I wore the devices in pairs, one on each wrist, for two days straight (switching wrists on day two), and I compared their step-count readings with the results from an Omron pedometer that I know to be reliable.
I also tested how well the devices recognised activities and how those results appeared in the apps. I took at least one walk and one bike ride of 15 minutes or longer with each tracker, as most devices need at least 10 minutes of activity to trigger a recording. I noted everything I did each day, and I compared the activity the trackers recorded against that written log. I also wore the devices to bed and compared their results against my actual going-to-bed and waking-up times (for sleep duration).
As most of the devices I tested have built-in heart-rate monitors, I noted the resting heart rates they recorded to see if those figures jibed with what I know mine to be.
How well does it record workouts? For all of the devices, I tested how well they estimated distance travelled by walking a mile on a treadmill – the devices all use algorithms to estimate stride length, which they multiply by the steps counted. (I also compared their step counts for that mile’s walk against those of my trusty pedometer.) For the devices with built-in GPS – as well as those that can borrow the GPS of a paired smartphone – I walked a marked 1.1-mile lap of Astoria Park.
For any device that tracks active heart rate during a workout, I performed two separate tests on the treadmill: a five-minute steady-state run at an easy pace, and a six-minute walk-jog-run of two minutes at each pace. I compared heart-rate readings from the device against an older-model Garmin with a chest strap at 30-second intervals, and for two minutes of recovery.
During all of the treadmill tests, I noted how easy (or difficult) it was to read the data display mid-workout.
How accurate is your tracker’s step count?
These trackers collect all kinds of data, including the number of steps you walk in a day, the kinds of activities you do, the intensity of your workouts and how well you sleep. But how accurate are they? It depends. Although fitness trackers tend to measure some activities well, they measure others quite poorly – including all-day step count.
Any device that you wear on your wrist is actually tracking the swinging of your arm, which – when you are walking or running – pretty closely matches what your legs are doing. But humans do a lot more than just walk and run, and these devices can and will perceive any movement your arms make – say, while you’re folding laundry or clapping your hands – as steps. In my tests, most of the devices inflated the number of steps I took by 15% to 30% compared with my pedometer. Conversely, if your legs are moving but your arms aren’t – you’re pushing a grocery cart, for instance, or a baby stroller – you’ll get shortchanged.
You can’t trust “all-day distance covered”, either. I often hear people proclaim, “My [insert wrist-worn device here] says I walked 10 miles today.” But these totals are based on step counts, which we know to be unreliable, multiplied by stride length – another imperfect estimate that the device makes. (You can measure and set your stride length in the device’s app, which will help somewhat.)
That said, these measurements do show trends from day to day and week to week, which is useful if you’re trying to be more active. And many devices do automatically recognise and record activities reasonably well, if not perfectly. Still, with any tracker, if you want the very best log, use a dedicated workout mode to record your session – launching it will turn on the timer, activate more sensors and even increase how frequently the device checks your heart rate.
There are also some other measures you should approach with caution. First, you shouldn’t use the device’s measurements of your active heart rate for training purposes. The trackers’ GPS accuracy (whether they have their own onboard GPS or use your smartphone’s GPS) is okay but not perfect. (GPS rarely is.) Second, you shouldn’t regard calorie counts as absolute. Most of the devices provide a tally of total calories burned that’s based in part on an estimate of your basal metabolic rate. The key word here is estimate. Don’t consider those numbers to be the gospel.
How well the trackers measured step count and distance
| Fitness tracker | All-day step count | Treadmill step count | Treadmill distance |
|---|---|---|---|
| Fitbit Charge 3 | 17.39% | -2.01% | 8% |
| Garmin Vívosmart 4 | 16.45% | -0.15% | 18% |
| Fitbit Flex 2 | 16.86% | -1.06% | 14% |
| Garmin Vívoactive 3 | 9.90% | 0.05% | -21% |
| Garmin Vívosport | 14.09% | 0.10% | -21% |
| Samsung Gear Fit2 Pro | -1.69% | -12.42% | -15% |
| Fitbit Versa | 26.41% | -0.60% | 16% |
| Garmin Vívofit 4 | 6.86% | 0.30% | -16% |
| Suunto 3 Fitness | -9.69% | 1.96% | 52% |
| Fitbit Alta HR | 15.40% | -1.06% | 20% |
| Letscom ID130Plus Color HR | 26.02% | -0.25% | 4% |
| Motiv Ring | 6.20% | 0.69% | 0% |
| Spire Health Tags | 0.51% | 0.05% | -10% |
I measured my overall step count with each tracker over the course of two days, wearing the wristband ones on my non-dominant hand to give them the best shot at accuracy – the percentages in the first column above show the daily average of how much each tracker differed from my pedometer’s count. I also wore each tracker for a mile-long walk on a treadmill (again, wearing the wristband ones on my non-dominant hand). The percentages in the second column show how far off each tracker was from my pedometer’s count on the treadmill. The third column is how far off each tracker was in measuring the distance (1 mile) that I walked in that treadmill workout.
Our pick: Fitbit Charge 3
Our pick
Thanks to its ease of use, superior accuracy and helpful app, the Fitbit Charge 3 is our top pick for tracking daily activity. Its SmartTrack feature allowed it to detect activities more accurately than any other tracker we tested, and it was better than many of the others when counting steps or measuring distances or heart rates. The touchscreen display, which works in tandem with an induction button in the device’s side, was intuitive to use, letting us respond to alerts and make adjustments quickly and easily from the device itself. Its app was the easiest to navigate of any we tested, and the most useful. The Charge 3 tracked sleep better than most devices too, managing to collect data from naps, which some other trackers (Garmin models, mainly) were unable to do.
The Charge 3’s activity-tracking features performed well in our tests, quickly and automatically picking up walks, bike rides and more after about 10 minutes of movement. As with all Fitbit models, you have to check the app to discover what activities your tracker has recorded. Also, as with most trackers, the Charge 3’s daylong step counts ran high, particularly on the day I wore it to a karaoke happy hour. (There may have been dancing involved.) Conversely, it consistently undercounted my step count on the treadmill, though by only 1% to 2%. Although the Charge 3 took longer than the Garmin Vívoactive 3 to find and hold on to my heart rate, I found that its heart-rate monitor also performed well on my treadmill tests.
The combination of the responsive touchscreen and a side haptic button (that is, not a mechanical button but an inductive sensor that reacts to pressure) makes the device intuitive to navigate. You can set the slim, black-and-white display to any of eight watch faces. The interface is smartly laid out, with simple, scrollable menus that use both labels and icons – some other trackers we tested show only icons, which can be less than clear. The screen stays dark until you lift your wrist – called “move to view,” this feature is intended to save power.
The Charge 3 has 20 exercise modes – more than most of its competitors. These include a useful, programmable interval timer and a decent swimming function, which many devices lack (and our runner-up does poorly). This tracker also can also borrow your phone’s GPS and create maps during outdoor workouts – of course, this feature works only if you carry your phone along with you. The Charge 3 offers friendly and encouraging reminders to move, displaying the number of steps left to hit your target for each hour.
Fitbit has the best app of any tracker we’ve tested. It’s highly user-friendly, and it connects you to a large and active social network, which can help motivate you to meet your goals. (We found other companies’ apps less effective on both counts.) In addition, you can use the app to log your food, water and caffeine intake, and those who menstruate can track their monthly cycles as well. You can also choose which app notifications appear on the display, and you can clear the notifications individually or all at once – many other devices we tested lack a “clear all” command. (Dismissing notification after notification can get very tedious very quickly.) If you’re an Android user, you can reply to text messages with any of five set messages and five emoji, which you can change in the app. (If you’re an iOS user, you’re out of luck.)
The Charge 3 seemed accurate when measuring my time asleep, including naps, and the sleep insights in the Fitbit app offered advice on ways to improve my sleep habits, which is a nice extra. You have to programme any alarms using the app, but you can turn them on and off using the device. The alarm vibration is robust even on the normal setting – the “strong” setting makes an audible buzzing noise, which could disturb a light sleeper in the same bed.
Fitbit says the Charge 3’s battery lasts up to seven days on a charge. After wearing the tracker for two days and two nights, I found that 82% remained – a promising result. It’s also nice that the battery meter shows as a percentage, rather than an imprecise icon as on some other trackers.
Flaws but not dealbreakers
The Charge 3 can record 20 different types of activity, but you can see no more than six activity modes at once. I found I had to add or remove workout types frequently because my usual rotation involves more than that: outdoor walk, outdoor run, treadmill, bike, swim, yoga, interval workout and weights. Also, although the device captured my data well in swim mode (it missed one length out of 35 on my freestyle test and added a bonus length to 10 lengths of breaststroke), it doesn’t show counted lengths in real time while you swim, which several other trackers do. It also limits you to setting a time goal for swimming – you can’t set one for distance (our also great pick lets you do so).
I found the standard plastic band that comes with the Charge 3 not as comfortable as some of the others I tested, you can buy additional bands and swap them out quite easily. (They’re not cheap, though.)
Finally, a few Amazon reviews – especially earlier ones – complain about phone-syncing problems (this happened occasionally with my Android phone, although restarting the phone always fixed it) and all-out bricking, which I didn’t experience at all. Fitbit customer service has always been very good about replacing faulty devices.
Runner-up: Garmin Vívosmart 4
RUNNER-Up
The Garmin Vívosmart 4 measures step count and heart rate about as accurately as our top pick. However, although the Vívosmart 4 also detects activities automatically, it doesn’t do so as well as the Charge 3, and it buries the records of those activities deep in Garmin’s app. The Vívosmart 4 does offer several workout modes that are easy to toggle through, so you can still record all kinds of activities – from running to yoga to strength training – but you have to be better about remembering to do so. This is one of the slimmest trackers we tested – only our budget pick takes up less space on a wrist, and that one has no screen at all. The Vívosmart 4’s display makes remarkably good use of its limited space. However, the touchscreen ceases to respond when it gets wet, which makes it useless in the pool. Finally, as Garmin’s online community tends to focus more on running and cycling, the informal support network for activity trackers is smaller.
The Vívosmart 4’s screen is smaller, of course, than that of the Charge 3, and the Charge 3’s display came to life more quickly whenever I looked my wrist. But the Vívosmart 4 has a number of features that make its black-and-white screen more useful than its small size would suggest, starting with large, horizontally scrolling type for your smartphone notifications that’s easy to read. Like the Charge 3, this tracker has a haptic button, which in this case helps you tab through menus or notifications. You can also remove menu elements you don’t need, reducing screen clutter.
As with most trackers, the Vívosmart 4’s step counts ran high in our tests, but they were, in fact, slightly closer to my pedometer’s totals than were the Charge 3’s. And its count during my one-mile treadmill test was stellar – only three steps short. The Vívosmart 4’s heart-rate monitoring is, like the Charge 3’s, accurate enough for occasional checks during a workout.
The Vívosmart 4 offers 10 exercise modes – half as many as the Charge 3. (As with the Charge 3, you can see at most six modes at a time.) But automatic activity tracking is the Vívosmart 4’s real weak spot. Garmin says that Move IQ (as Garmin calls its auto-tracking feature) will recognise and record a range of activities – for walking and running, you can set the Vívosmart to trigger a timed workout mode after as little as five minutes of walking or a minute of running. Unfortunately, this feature didn’t work very well for me. The tracker often confused my walking for running, regularly creating “running workouts” when I was only strolling down the street. I turned that function off entirely. Afterward, whenever the device automatically detected and recorded activities, it buried the workouts in a hard-to-navigate calendar section, rather than logging them in my activities section. To cap it all off, the Vívosmart 4 is supposed to be able to track swims, but it prompts you to enter the number of lengths you swam rather than count them for you, and the touchscreen ceases to work entirely when wet.
The Vívosmart 4 lets you know when you’ve moved enough to satisfy your hourly quota, but it doesn’t offer the nice step-count reminders the Charge 3 provides. The home screen of the Garmin app, which displays your data in cards that you can reorder as you like, is simple to read at a glance, but the menus are deep and confusing. Garmin’s social network also isn’t as large or active, especially for non-runners, as Fitbit’s.
You can dismiss smartphone notifications only individually on the Vívosmart 4, not en masse. Whereas Android users can select which apps send notifications and can reply to text messages with canned replies, iPhone users can’t do either. For occasions when you don’t want any wrist notifications at all (say, during a meeting), you can activate “do not disturb” on the device quite easily.
I found the Vívosmart 4 the comfiest tracker to wear when sleeping. However, this Garmin tracker doesn’t record naps at all, and it’s not good at distinguishing between reading or watching TV in bed and falling asleep, or between waking up and lounging in bed before actually getting up. You can go into the app to trim those too-long sleep times, but then you lose the advanced sleep-tracking details – the tracker reverts instead to what it measured using movement alone.
The battery, which is meant to last up to seven days, fared well in our tests. After two days and nights of use, it looked to be about 80% full. (The battery meter is an icon, not a number.) The Vívosmart 4 comes in two sizes (small/medium and large) and several colours of band – you can’t replace or change the band, though.
Budget pick: Fitbit Flex 2
Budget pick
The Fitbit Flex 2 is the slimmest and least obtrusive wristband tracker we tested – the trade-off being that it has no screen at all. It does, however, come with the same great Fitbit app that the Charge 3 uses, the same great Fitbit social network and the same SmartTrack automatic activity detection. This wear-it-and-forget-it device measures activities competently, is comfortable to wear all day long and has battery life nearly as good as that of our other picks.
Like the Charge 3, the Flex 2 can detect a wide range of exercises – from walking to running to cycling to swimming to using the elliptical machine and more – very well, and it can differentiate among them too (all at a price less than that of the Charge 3). Unlike the Charge 3, though, it doesn’t let you select a workout mode on the device itself. You just have to trust that the Flex 2 will do its thing. Fortunately, it usually does. If it fails to pick up an activity, you can enter it on the app.
In terms of overall accuracy, the Flex 2 compared well to the other trackers we tested. Its all-day step counts were a little high, and it overestimated how far and for how long I swam in my pool test. That’s not unusual for fitness trackers, though – and the Flex 2 undercounted the steps I took during my mile-long treadmill walk by only about 1%.
The biggest drawback – is the lack of a screen. Instead of communicating using text, the Flex 2 blinks its five coloured LEDs and vibrates to tell you that you’ve hit a goal or to remind you to move or to indicate that the battery is low. You can also set it to flash and vibrate in different patterns to indicate incoming phone calls or text messages, but to me, memorising the meaning of each pattern wasn’t worth the trouble. You can double-tap the tracker to get an estimate of how close you are to your next step goal (each LED equals 25%), but otherwise you have to check your progress on the app.
The Flex 2 doesn’t have a heart-rate monitor, which means sleep tracking is based on movement alone, but I still found it reasonably accurate in measuring how long I slept. It has an alarm that you can set in the app, but it was too weak to wake a heavy sleeper. The battery life is rated at five days, two days less than what our other picks promise – my two-day/two-night test used up about half the battery.
I found the included band, which comes in two sizes, comfortable enough for round-the-clock wear. That band can be fussy to fasten – you can, if you like, remove the tracker itself and put it in a range of bands in other sizes or materials, including a gold-plated bracelet that Fitbit sells.
Also great: Garmin Vívoactive 3
Also great
The Garmin Vívoactive 3 is our pick for the fitness fanatic who wants to track a wide variety of workouts, or anyone who strongly prefers a large, easy-to-see colour display. Its heart-rate and step-count readings were among the most accurate we found. It also has 20 built-in workout modes (any or all of which you can select on the watch). Plus you can create as many of your own modes as you like.
On my treadmill step-count test, the Vívoactive 3 gave me the best results of all the trackers – it was just one step over. Like all the other trackers, it over-counted my all-day step count (especially on laundry day), though not as egregiously as others. In the pool, the Vívoactive 3 nailed the length count by the time I finished my freestyle workout, though it was a length behind during the workout itself (this isn’t uncommon, as most devices lag in registering turns). However, the Vívoactive 3 detected activities no better than the Vívosmart 4 did, and it too tended to mistake walking for running.
In my tests its heart-rate monitoring performed the best, both in terms of accuracy and how easy it was for me to see my data clearly on the display. Still, if you intend to train by heart rate, you should pair this tracker with a compatible chest strap for greater accuracy – this is the only one of our picks that lets you do so.
The Vívoactive 3 was a solid contender in our GPS running watch guide, but the touchscreen was its Achilles’ heel – most of the runners we talked to said they preferred buttons, which are more precise and work with sweaty hands in summer and gloved hands in winter. True, you start and stop runs by pushing the button on the Vívoactive 3’s side, but you still have to tap the screen to create laps. That said, I was impressed with how responsive the screen was, especially when I was swimming. Unlike the move-to-view displays on the Charge 3 and the Vívosmart 4, this passive-LED screen never goes entirely dark. The device comes loaded with a handful of watch faces, and dozens more are available in the Garmin Connect store.
As was the case with the Vívosmart 4, the Vívoactive 3’s smartwatch notifications work better for Android users: you can select which notifications you’d like to see on the watch, and you can reply to texts with a few canned responses. If you’re an iPhone owner, you’re stuck with getting any and every notification your phone gets. Whether you’re using an Android or an iPhone, you have to dismiss the notifications one at a time, which can be tedious. (Or pull out your phone and clear them all there – then they’ll disappear from the device, too.)
Its sleep tracking suffers from the same shortcomings I saw in the Vívosmart 4. Being larger, the Vívoactive 3 was less comfortable to wear to bed than our other picks. That said, the vibrating wake-up alarm is strong and silent, and you can set it quickly on the device itself – you don’t have to dig out your phone and launch the app.
Garmin says the Vívoactive 3’s battery will last up to seven days, though that drops to 13 hours if you keep it in GPS mode. After I used it for two days and nights – occasionally enabling the GPS – it was down to 55%.
Should you get an Apple Watch instead of a fitness tracker?
After the autumn 2018 updates to watchOS 5, which includes a slew of fitness-focussed features, including automatic activity detection, I started getting a lot of questions about it. So I tested both a Series 3 and a Series 4 Apple Watch, both updated to watchOS 5, using the same tests I performed for activity trackers (and for GPS running watches). Here’s what I discovered: if you have an Apple Watch already, it’ll work fine as a fitness tracker. If you really want only a fitness tracker, though, you can get a very good one – the Fitbit Charge 3 – for a lot less money. (If you’re just looking for an excuse to buy an Apple Watch, that’s another thing entirely.)
The Apple Watch measures activity differently than other trackers. Instead of focusing on step counts, it sets minimum exercise goals (30 active minutes) and aims to get you on your feet at least once an hour for 12 hours of your day. It also allows you to set a goal of “active calories”, which is how it keeps track of your total daily movement (to arrive at this, it estimates your basal metabolic rate and mixes in the movement it detects and your heart rate). If you dig into the interface, though, you can find your step counts. For me, they tended to be 6% to 9% too high on the Apple Watch, which is still better than what I saw from most devices.
The watch triggers a timed workout mode for certain activities – walking, running, swimming, rowing, using the elliptical machine – whenever it detects anywhere from three to 10 minutes’ worth of that activity. This feature generally worked pretty well for me, although on a few occasions the watch thought I was on an elliptical machine when I was really walking with an umbrella or a water bottle in my hand. (An Apple representative told me this was a known glitch and was being patched in a software update.)
Launching a workout mode (you have 12 to choose from) gives you more accurate data. I tested it indoors, for walking and running – it nailed the 1-mile distance on the treadmill. To record outdoor runs, it uses either its onboard GPS or the GPS from your phone (the latter saves watch-battery life) – my results were good but not perfect, as you might expect with GPS tracking. In the pool, it did an excellent job of measuring my total distance and detecting stroke type.
The active heart-rate monitoring disappointed me, though. The tests with the Series 4 started out fine, but as I got going into my run, my heart-rate reading would spike weirdly to 180 or 190 bpm. I futzed with the band to tighten it, slid it farther up my arm, and later conferred with Apple’s PR team to no real solution. The Series 3 tests yielded similar results – a good start and then strange spikes when it detected my “heart rate.” It would also grey out occasionally, indicating it was having trouble detecting anything.
If you do have an Apple Watch and want to use it as an activity tracker, you’ll need at least three apps: the Watch app to control the device’s settings, the Activity app to parse movement and workout data, and the Health app to create a holistic picture of your habits. To track your sleep as well, you’ll have to download yet another app from a third-party vendor (I tried and liked Sleepwatch).
What to look forward to
The French company Withings, which Nokia bought several years back and then spun off again in summer 2018, recently announced the Pulse HR, a wrist-worn activity tracker with a claimed battery life of 20 days.
The Huawei Band 3 Pro offers a colour screen, built-in GPS, and swim tracking while the Huawei Band 3e can sit on the wrist or the foot to offer running guidance.
The competition
Our former top pick for fitness trackers, the Garmin Vívosport offers onboard GPS in a slim fitness tracker. However, if your aim is to track runs or bike rides seriously, you’re better off with a dedicated GPS running watch. As an all-around fitness tracker, the newer Fitbit Charge 3 outperforms the Vívosport (better auto activity tracking) and the Garmin Vívosmart 4 costs less than it does.
Another former pick in this guide, the Samsung Gear Fit2 Pro is a smartwatch-like activity tracker that plays almost as nicely with iOS as with Android (the main difference is that you can’t reply to texts on an iPhone). It’s a capable, attractive activity tracker, but it has one major drawback: short battery life. Samsung claims it will run for three days, but I barely eked out two.
The Fitbit Versa offers a mix of smartwatch and activity tracker features, and its large, squared-off touchscreen is attractive and easy to navigate. But it has fewer activity settings than the Vívoactive 3, and its app offerings are not robust enough for it to compete as a smartwatch.
The Fitbit Ionic, Fitbit’s first foray into the world of true smartwatches, struggles to justify that label. It offers few apps and doesn’t handle notifications well. The only feature it has over the Versa is onboard GPS, which doesn’t justify its higher price tag.
The best thing the Garmin Vívofit 4, a former pick for basic fitness tracking, has going for it is that you don’t need to charge it at all – it runs on a watch battery that’s good for a year. But it costs more than the equally basic Flex 2 and offers fewer features – although it does have a display. It’s also dated-looking.
I love what Suunto is aiming to accomplish with the Suunto 3 Fitness watch – a workout-oriented companion meant to encourage you to follow a training plan and fit more exercise into your life – but it offers no detailed sleep tracking, no automatic activity detection and no reminders to move (although it will tell you if today is a workout day). The button-only interface is confusing.
The slim-design Fitbit Alta HR may appeal to people who want Fitbit’s superior sleep tracking and automatic activity detection. But it isn’t waterproof, you can’t select any activity modes, and it has limited phone notifications.
Non-wrist wearables
The Motiv Ring takes activity tracking from the wrist to the finger. The titanium-covered band is chunky but not uncomfortable, and its raw step count from my treadmill test was better than those of the Fitbit models and almost as good as those of the test-topping Garmin trackers. But its sleep tracking is far less detailed than that of our picks, and it lacks timed activity modes, smartphone notifications and reminders to move. It’s also expensive, and it can go for only three days between charges.
Spire Health Tags are plastic heart-rate-enabled trackers measuring 2 by 1¼ inches, and about ¼ inch thick. You stick the Health Tags to the inside of your clothing – they come in multipacks, so you can distribute them throughout your wardrobe. I hardly noticed them once they were in place. The companion app is the only way to view your data, though, and I found it confusing to navigate. I liked the presentation of the sleep-tracking data best – bar charts and tallies of minutes spent awake and at different depth of sleep. So far, the app is only for iOS, but the company says an Android version is coming.
