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 4? 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.

Until it launched its new Fitbit Ionic smartwatches Fitbit didn’t actually label its wristbands as smartwatches. Its old Surge device was dubbed a “superwatch”, and it called the Blaze (also now discontinued) a "Fitness Watch". Otherwise, the correct term is activity trackers.

Aside from the Ionic and Versa, 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 many 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 new Series 4) vs the Fitbit Alta HR, Fitbit Charge 3, Fitbit Versa and Fitbit Ionic. The Fitbit Flex 2 is the cheapest wristband but has a far more minimal display screen, and no watch function. 

Fitbit Ionic smartwatches

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 wristbands (excluding the Flex 2, Alta and Alta HR) 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 3, Ionic and Versa supporting running, cross-training, biking, strength and cardio workouts.

Serious runners dismissed the original Apple Watch 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 Ionic.

The Series 2 Watch has been replaced by the Series 3 and Series 4, which have faster processors and better battery life. A version of each 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 Ionic, 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 trackers and 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. 

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 taptic 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 work in the same way, and are found on the Flex 2, Alta, Alta HR, Charge 2, Versa and Ionic.

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.

Fitbit vs Apple Watch heart rate monitor  

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

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 has 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.

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

The Apple Watch has the ability to detect and warn of a prolonged elevated heart rate when not exercising, and, with Series 4, 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). The 4 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.

By placing a finger on the Digital Crown of the Series 4 Apple Watch you can get the watch to run an electrocardiogram (ECG) test on you, which Apple says marks the first time an ECG device has been made available over the counter direct to consumers - although just for US users right now (although if you change your region setting...). Read Macworld's explainer for more on How to use the ECG feature on Apple Watch Series 4.

Apple Watch vs Fitbit tracker calorie counters

Calorie counting

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 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.

Sleep on Apple Watch and Fitbit

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 - so sleep monitoring isn't built in. You can install a sleep monitoring app, but you might have to charge your Watch during the day, which isn't ideal. The Series 3 and 4 Apple Watch's battery life is much improved, however, so can (on light, non-GPS use) last nearly three full days and two nights.

See the screens above to compare the Fitbit Sleep screen and the third-party Apple Watch sleep app Sleep Watch, which you need to download separately and pay for. You can see that the two apps were pretty close on measuring the time I was asleep (not a great night, I admit, but you try sleeping while wearing two devices!).

We found that the auto-sensing sleep function on the Fitbit worked a lot better than on Sleep Watch, which sometimes took relative inactivity on waking as continued sleep. Fitbit also goes into much greater detail on the different Sleep Stages you go through. 

If you use Fitbit Alta HR, Versa, Charge 2 or Ionic 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.

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

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 and Ionic work with the Fitbit Coach, which combines dynamic video workouts with Audio Coaching sessions to help users increase endurance, speed and form. With (introductory) pricing of £7.99 a month, Fitbit says the app will grow to include advanced tools with a library of programs and workouts to deliver personalised adaptive health and fitness coaching.

The Versa and Ionic 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 or Ionic 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.

Apple Watch design fitness

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