Want an activity tracker but can’t decide whether to buy a Fitbit wristband or fork out for the rather lovely Apple Watch, now at Series 6? We pit Apple Watch vs Fitbit to see which comes out best on various aspects: fitness tracking, heart-rate monitoring, design, price, apps, battery life, and so on.

Apple is known for its smartwatches, and Fitbit for its activity trackers. But the boundaries and functions are getting blurred with Fitbit adding apps and lovely touchscreens to its trackers, and Apple adding more health features to its Watch.

Aside from the Sense and Versa family, Fitbits don’t run multiple apps like a smartwatch, but they are directly comparable on many of their fitness-measuring functions, design themes and functions. And most feature on-wrist notifications such as Caller ID and Texts - which, to be fair, are the most used non-fitness apps on most smartwatches anyway.

As a direct comparison, we’ll look at the Apple Watch (including the Series 3, and new Watch SE, and new Series 6 vs the Fitbit Charge 4, Fitbit Versa 2, Versa 3 and Fitbit Sense. Read our Fitbit Charge 4 review, Fitbit Versa 3 review and Fitbit Sense review.

Both Apple and Fitbit make excellent products, so it's a matter of deciding which features really matter to you. We will focus on health and fitness as a core requirement, but there is more to both brands than just these functions.

Fitbit Sense vs Apple Watch 6

Activity tracking

Keeping fit doesn’t mean you have to be a gym freak or marathon runner. Keeping active throughout the day offers real health benefits too, and both the Apple Watch and Fitbit activity trackers are superb at getting you moving more.

The Apple Watch and Fitbit activity trackers measure steps taken, distance travelled and calories burned. They also show you how many minutes you’ve been active during the day. Each tracks your progress over time and can store historical data, and you set daily goals for yourself.

Apple Watch Activity app display

In addition, the Fitbit smartwatches (excluding the Versa Lite Edition) have a barometric altimeter that counts distance climbed (take the hilly route home, not the flat one). The Fitbits also sync weight data from optional Fitbit Aria scales.

As a result, the Fitbit models range from everyday fitness and active fitness (just like the Apple Watch) and further to sports and performance fitness - with the Charge 4, Sense and Versa 3 supporting running, cross-training, biking, strength and cardio workouts.

Serious runners dismissed the original Apple Watch and Fitbit for their needs, preferring the Ionic or other dedicated running watches from the Garmin or Suunto. But that changed with the release of the Series 2 Apple Watch, which featured a built-in GPS just like the Fitbit Charge 4, Versa 3 and Sense (plus older Versa 2 and Ionic).

The Series 3 Watch and Series 6 Watch have faster processors (the 6's processor is much faster so loads apps quicker) and but still weak battery life. A version with built-in 4G is also available so it can work without having to take your iPhone with you when you exercise.

This makes it a closer match to the Fitbit Sense and Versa 3, which (with similar built-in GPS, onboard music, notifications and contactless payments) can take care of most of your exercise needs without requiring you carry a phone or wallet around.

Fitbit Family trackers scales

Fitness is obviously at the core of the Fitbits, whereas the Apple Watch counts activity tracking among its many features.

The Apple Watch offers two main fitness apps: Activity, which is all about health, movement, wellness and your daily routine; and Workout App, which tracks running, cycling and walking. All this data is collected on your iPhone via the Activity app, although you can get a more holistic view of their health by using the Health app on your iPhone, which integrates data from multiple sources, not only the Watch. 

In watchOS 7, new workouts will include Core Training, Dance (tested with Bollywood, cardio dance, hip-hop, and Latin), Functional Strength Training, and Cooldown. 

Read here for some great tips and advice on how to use the Apple Watch Activity app.

While they work brilliantly with the iPhone, Fitbits do not officially support Apple’s Health Kit, although integration is offered by third-party apps.

You can see at a glance how far you are with your daily movement and health goals by looking at the Apple Watch’s colourful three rings, which light up to show your progress. The Move ring shows calories burned. The Exercise ring displays how many minutes of brisk activity you’ve achieved. And the Stand ring shows how often you’ve stood up to stop sitting down. The aim is to complete each ring every day. It’s a great motivation tool.

Apple defines exercise as any activity that’s equivalent to at least a brisk walk. The Watch looks at your heart rate and movement data, so just going for a walk might not move that green ring as much as you’d think. It wants you to get your heart pumping a bit faster. The Apple Watch learns your habits so will push you harder the more active you get over time.

We love the Apple Watch’s ping to remind you if you’ve been sitting around too long – time to stretch the legs and get the heart rate up for a bit, or at least stand up. Basically, it’s a get-off-your-arse alert, from the haptic pulses to your wrist to notifications, that you’ve been idle for a long period of time. You can actually get an alert even when standing up because what the Watch is actually measuring is your lack of moving about.

Fitbit's Reminders To Move works in the same way, and is found on all Fitbits.

The Apple Workout app gives you real-time stats for exercise time, distance walked/run, calories burned and pace, and with the update to watchOS 4, it got a whole lot better. It's easier to use, but importantly now works with 80 percent of gym equipment so you'll get the data from the running machine or bike you use at your local.

Apple Activity vs Fitbit app

Setting goals: Fitbit wins

One big difference here is that Apple doesn't let you set yourself goals for steps or other metrics, except for calorie burn. If burning calories is not your prime objective, then this is a definite limitation of the Watch. 

In comparison, Fitbit allows you to set yourself specific goals for Steps, Distance, Calories Burned, Active Minutes, Floors Climbed and your Hourly Activity Goal.

Heart-rate monitor: narrow Fitbit win

The Apple Watch and heart-rate-checking Fitbits use something called photoplethysmography to measure your heart rate. This uses green LEDs on the underside of the wristband to detect blood volume and capillary-size changes under pressure. When your heart beats, your capillaries expand and contract based on blood volume changes. The LED lights reflect onto the skin to detect blood volume changes.

Blood is red because it reflects red light and absorbs green light. When your heart beats, the blood flow in your wrist – and the green light absorption – is greater.

The Fitbits monitor your heart rate continuously, 24/7. They can store heart rate data at 1-second intervals during exercise tracking and at 5-second intervals all other times.

On the other hand (or should I say wrist?) the Apple Watch checks your heart rate only every ten minutes during the day. However, it does record your heart rate continuously when the Workout app is turned on, so you get constant feedback during training sessions. The Watch’s built-in heart-rate monitor does support external heart-rate monitors too.

Also, in watchOS 4, Apple improved the Heart Rate app which now measures your resting heart rate and your recovery heart rate, and can give you notifications if anything seems awry.

The Apple Watch Series 6 comes with watchOS 7 pre-installed. watchOS 7 features a raft of new features, including sleep tracking, new workouts, weekly listening summaries to show how long you’ve listened to high-decibel sounds, cycling directions, and sharable watch faces.

Fitbit says that the Sense and Versa 3 have also improved heart-rate measurement, as the LED sensors have closer contact with the wrist.

The Apple Watch has the ability to detect and warn of a prolonged elevated heart rate when not exercising, and is able to spot low rates too (which could be a sign of bradycardia, when the heart is not pumping enough oxygen-rich blood around the body). It also looks out for irregular heart rhythms, notifying you of a potential atrial fibrillation.

Patients visiting doctors often complain of heart problems that aren't happening right then, so having detailed and long-term heart data on file in the Health app is potentially beneficial.

However, Stanford University's Apple Heart Study, funded by Apple to determine the Apple Watch's accuracy in detecting irregular heart rhythms, revealed that the Apple Watch can indeed detect AFib, but the majority of warning notifications ended up being false alarms; note that the tests used the pre-version 4 Watch.

Fitbit vs Apple Watch SP02 blood oxygen

Checking heart irregularities: Apple win

Measuring heart rate also allows for the devices to check when the heart’s rhythm is irregular - which can be a sign of atrial fibrillation (AFib), a leading cause of stroke.

Both Apple and Fitbit include the ability to measure a person's electrocardiogram (ECG) signal and blood-oxygen saturation (SpO2) level.

The Fitbit Sense and Apple Watch include ECG tests. For example, by placing a finger on the Digital Crown of the Watch you can get it to run an electrocardiogram (ECG) test on you. 

Both the Apple Watch and the latest Fitbit smartwatches offer SP02 sensors to detect AFib. Both allow on-demand readings of your blood oxygen.

The new Apple Watch can take a blood O2 reading in just 15 seconds at any time of day, while Fitbit only measures your blood-oxygen levels while you sleep, and you have to remember to switch the clock face for it to take a reading.

Each ECG app is CE marked and cleared in the European Economic Area and FDA-approved in the US.

Apple Watch vs Fitbit tracker calorie counters

Calorie counting: draw

The basic formula for losing weight is to count calories in and ensure you are expending more calories out through exercise. Both the Watch and Fitbits help you count these calories.

The Apple Watch uses motion and heart rate data to determine calorie count, which then dictates the Move metric of the Activity app. As you continue to wear your Apple Watch it will better learn your habits, average heart rate ranges, and normal activity levels, helping to make calorie counts more accurate.

Unlike Fitbit, Apple splits apart "resting calories" (calories you burn just by existing) and "active calories" (burnt through more vigorous activity). The Move ring is interested in Active, not Resting calories, which is a little more rigorous than Fitbit’s approach. Fitbit allows for "resting calories" too. 

Your Resting Metabolic Rate (RMR) is the amount of calories that your body burns while you are at complete rest (with muscles relaxed, such as asleep) to keep itself alive (sustain vital organs such as your heart, brain, nervous system, lungs, kidneys, liver, muscles, and skin) and digest food. (Technical bit: Resting Metabolic Rate is not the same as Basal Metabolic Rate (BMR), which excludes the calories burned digesting food.)

If you set your calorie-burn target high on the Apple Watch you'll need to walk the equivalent of 20,000 Fitbit steps.

However, some Apple Watch owners have complained about calorie-counting inaccuracies, which might be down to the Watch's occasional inability to accurately record distance (and the fact it doesn't detect exercise automatically: you have to tell it you're cycling, running etc). The Versa and Ionic recognise when you’re running and automatically enter Run Mode - starting the GPS or connected GPS - and even automatically pause when you do.

Fitbit estimates the number of calories burned based on your BMR (Basal Metabolic Rate), calculated using your height, weight, age, and gender. The trackers that measure heart rate go into more detail,  with the calorie burn estimate taking heart rate into account.

Fitbit calorie tracking begins at midnight and incorporates the calories burnt while sleeping – which is obviously missed by the Apple Watch that has to charge overnight. When you sync your tracker, Fitbit replaces the estimated calorie burn with your tracker's data.

You can also manually log fitness activities, so the calories burned during those activities are also taken into account. When you log your meals each day you can set a Fitbit Food Plan that estimates your daily calorie consumption, and records the number of calories you have burned and eaten so far in the day.

Apple Watch vs Fitbit Sleep Tracking

Sleep monitoring: another Fitbit win

Scientists are increasingly linking weight gain and poor metabolism to sleep deprivation, so getting a good night's sleep should be part of your health, fitness and weight-loss strategy. Sleep loss can lead to an increased prevalence of diabetes and obesity. We should all be aiming for 8 hours of sleep per day. 

8 hours is a worthy aim, but unrealistic for many (such as parents!). Between 6 and 7.5 hours is maybe a goal you'll hit more often.

Because its battery life is limited (see below), Apple recommends the Watch be charged every night. The Apple Watch's battery life is much improved, however, so can (on light, non-GPS use) last nearly three full days and two nights.

But that is not as impressive as Fitbit battery life that can last a week or more between charges.

With watchOS 7 Apple adds a Sleep app to the Series 3, 6 and entry-level SE Watches. It helps you establish a regular bedtime routine and keep track of your sleep trends night after night.

Apple Sleep uses motion sensors, heartbeat sensors, and microphones to detect micro-movements to track of how deeply users are sleeping. Watch will sync with the iPhone or iPad to show visualisations of the periods of wake and sleep, plus a chart showing weekly sleep trends.

Comparing Apple's Sleep app to Fitbit's is revealing, as my colleague David Price describes in his otherwise glowing Apple Watch 6 review. Despite loving the latest Apple Watch, he still replaces it with a Fitbit at bedtime!

He writes: "Sleep tracking is the biggest disappointment with the Apple Watch. Its data is so facile compared to that of a decent-quality Fitbit that it barely seems worth the effort".

If you use Fitbit Inspire 2, Versa 3, Charge 4 or Sense to track your sleep, you can see a record of the Sleep Stages you cycle through at night. While you’re asleep each night, your body typically goes through several sleep cycles: Light Sleep, Deep Sleep, and REM sleep that’s associated with dreaming.

Fitbit also goes into much greater detail on the different Sleep Stages you go through, and now offers a nightly Sleep Score on the quality of your sleep. 

Sleep stages are traditionally measured in a lab using an electroencephalogram to detect brain activity along with other systems to monitor eye and muscle activity. Fitbit’s trackers can’t match this level of medical accuracy but can estimate your sleep stages every night.

Fitbit estimates sleep stages using a combination of movement and heart-rate patterns. While you’re sleeping, your device tracks the beat-to-beat changes in your heart rate, known as heart rate variability (HRV), which fluctuate as you transition between light sleep, deep sleep, and REM sleep stages.

 Fitbit vs Apple Watch 2016

Apps: Fitbit wins on fitness, Apple on everything else

Apple’s Activity and Workout apps look glorious, of course, but Fitbit’s appealing multi-phone app features more stats and data graphics. Fitbit also wins by having a rich desktop dashboard to collect and organise your activity data.

The Versa 3 and Sense work with the Fitbit Coach and Premium, which combine dynamic video workouts with Audio Coaching sessions to help users increase endurance, speed and form. With pricing of £7.99 or $9.99 a month, Fitbit says its Premium service will grow to include advanced tools with a library of programs and workouts to deliver personalised adaptive health and fitness coaching.

Apple is soon to release Fitness+ with workouts and trainers for £9.99 or $9.99 a month. 

The Versa 3 and Sense might measure up better against the Apple Watch when they have a much-expanded range of non-fitness apps. Right now its apps are very limited outside of Fitbit's impressive health and fitness functions, plus notification features - but more are being released, and there are over 500 to download. If you want a large range of non-health apps then the Watch or an Android equivalent will suit you better than a Fitbit, although they do feature Caller ID, text message and calendar alerts on screen.

Wearing both Watch and Versa 3 and Sense we found that the most used Apple Watch apps were Notifications, which are ably handled by the Fitbit smartwatches too - and in a less graphic way by the less smart Fitbit trackers too. If the Apple Watch has a "killer app" it's probably Activity - so the Fitbits compete very favourably for the most-used daily apps despite offering fewer third-party apps.

Other Apple apps include Calendar, Camera Remote, Weather and Apple Maps. And there's a huge range of downloadable apps for the Apple Watch.

With the Watch, you can also create an album of photos stored on your watch and share these with people. You can also create a Watch face with one of your photos as the background.

The Fitbits are limited almost exclusively to fitness features. In addition, the Inspire 2, Charge 4, Versa 3 and Sense all feature Caller ID and Text notifications, buzz and show on screen who’s calling when your phone (iPhone, Android or Windows Phone) rings.

The Sense and Versa also have on-watch music controls (not the Versa Lite Edition), and 2.5GB of storage - enough for 300 songs, or your favourite podcasts and audiobooks. There's a Weather app also included on the Fitbit smartwatches, and Coach on-screen video workouts on the Versa 3 and Sense.

Apple Watch design fitness

Continues on the next page.