Price: £79
Rating: 8

Keep fit wristbands such as the Fitbit Flex are becoming a popular way of monitoring and prompting better exercise and health through wearable technology. See also: Which Fitbit is best?

Keeping fit and using computers didn’t used to go together. Sitting in front of a screen for hours doesn’t burn calories or do anything for your posture.

That was before we could carry our computers around with us, and even exercise with them. There are plenty of running apps for the iPhone and Android smartphones that will work out how you’re doing while you work out.

Top 10 tips for hitting your Fitbit step goals

The advent of wearable computing and activity trackers puts tech at the heart of the modern keep fit fanatic. Stats, alerts, prompts and more stats make even boring exercise fun.

There are several wireless keep fit wristbands available today, including a wide range from Fitbit plus rivals such as the Jawbone Up24 and Misfit Shine.

More: Fitbit Charge review Fitbit One review Fitbit Zip review Fitbit Charge HR review (available "early 2015") Fitbit Surge review (available "early 2015")

Fitbit has several fitness products and apps. We liked the Fitbit One, which is a little gadget that clips onto your belt or can be carried in a pocket. A potential pain with the One was that it’s quite easy to lose, with the usual knocks and scrapes a body can get itself involved in during the average day. I lost mine at a children’s party – not an average day (thanks goodness!), but regular enough to pose a risk of loss for the tiny gadget.

Fitness wristbands like the Fitbit Flex remove this risk by being more firmly attached to the body and easier to monitor that it’s still in place. If wearing a wristband doesn’t appeal to you the Fitbit One is a good alternative.

Wearing a fitness wristband is just like wearing a watch. After a few minutes you forget you’re wearing it at all. They’re light, and most are stylish enough for hip keep fit fans to show off. The Flex is smart but it's not a watch, as the display shows just dots not figures. A new, pricier Fitbit wristband, the Fitbit Charge, does show the time and other activities on its display.

The Fitbit Flex is lightweight and available in in ten colours: Black, Slate, Tangerine, Teal, Navy, Violet, Blue, Lime, Pink and Red. You can buy extra bands (without the tracker) for £12.99. For the best prices see the end of this review.

You get two wristbands in the package – one small (140 - 176 mm) and one large (161 - 209 mm), so most wrist sizes are catered for. If you want to check before you buy that it will fit your wrist you can download and print out the two sizes to cut out and try for size.

A small tracker fits into the wristband, and this needs charging every five days or so. As the tracker itself fits into the wristband you can change bands when one wears out or you just fancy a change of colour. This isn't possible with most fitness wristbands.

You wear the Flex all day long, and it’s fully waterproof so you needn’t take it off for a shower, bath or swim, although Fitbit doesn't recommend extended exposure to water.

Why wear the Flex all day and night? Because it monitors not just your activity during the day but how you sleep at night, too.

What does the Fitbit Flex monitor?

Here’s what the Fitbit Flex monitors and measures using its smartMEMS 3-axis accelerometer technology. The Fitbit One, Charge, Charge HR and Surge also boast an altimeter that measures stairs climbed.

When you’re awake the Flex tracks the number of steps you take, the distance these steps mean you have travelled under your own steam, calories burned and minutes you are “very active”.

Sadly it registers barely a footstep for fitness activities such as swimming or cycling. I cycled 10 miles and the Flex counted that as a measly 2,500 steps – nothing like the effort I put into that bike ride. Also a 500m swim counted for next to nothing. Some fitness wristbands allow users to input other exercise data.

You can see how you're doing via the desktop dashboard or the iOS and Android apps. Here's what you might see using the iPhone app, for example.

Fitbit: goals and badges

You can set goals for each of these measurements, and earn badges for goals achieved.

The calculation of steps taken is never going to be 100 percent accurate but the distance isn’t way off in our tests. The thing to remember is that the measurements are relative. You’ll soon get an idea what you get up to in an average day, and you set out to beat that average and walk or run more, climb stairs rather than take the lift, leave the car in the driveway or walk past that bus stop.

You can input your weight every day but this isn’t compulsory so don’t let that put you off. Fitbit sells a £99 Aria Wi-Fi Smart Scale that tracks your weight, body fat percentage, and BMI. It wirelessly syncs your stats with online graph and mobile tools.

You can also create a daily calorie count and log meals to help you reach your weight goal. The food database used by Fitbit is from the US, so is pretty useless for UK users, but you can sync the Flex with other, better calorie-counting apps.

Fitbit Flex: monitoring sleep

When you’re ready for sleep you tap the Flex five times and it notes that you are now in sleep mode. The Flex tracks both the number of hours slept (until you tap five more times when you get out of bed) and the quality of that sleep (eg. restlessness). I'm not sure I believed the data that I woke up several times during the night but it's a handy way to check your getting enough shut eye.

Helpfully, the Flex has a silent wake alarm that gently vibrates to wake you at your desired time, without disturbing anyone else.

You set alarms using your computer or mobile device. Silent Alarms can be configured to recur every day, or on particular days of the week. You can set up to eight alarms on your Flex.

The alarm notification repeats three times, or until dismissed. You dismiss the alarm by tapping a few times after the vibration has stopped. If you do not dismiss the alarm, the Flex alarm repeats in nine minutes.

Fitbit Flex: syncing and monitoring data

You sync your activity data to your Mac or PC using the supplied Wireless Sync Dongle that plugs into a computer’s USB slot, and uses Bluetooth 4.0 to connect.

The Flex syncs automatically whenever it’s within about 20 feet of the dongle. All you need to do is download the Fitbit Connect application. This gives you access to a dashboard full of stats and graphs tracking your activity.

More fun and even easier is to use your smartphone or tablet to sync the Flex to via the free app (iOS, Android and Windows Phone).

Syncing to your phone is great as you can set notifications on the go when you are close to your pre-set goals to keep you motivated.

The Flex also gives you a gentle vibrating buzz on the wrist when you hit those goals.

Fitbit: compete with friends

While setting yourself goals is a good push to keep up your motivation there’s nothing like a little competition, and Fitbit allows you to track your exercise against other Fitbit-wearing friends. There’s a leaderboard on the website and on the app.

Fitbit Flex: Stats and graphs

On the desktop site and via the mobile app there are tons of gorgeous-looking graphs and stats to keep an eye on.

Fitbit sends out a weekly email of your stats so you can easily keep up on your progress. It will also compare your stats with the people you are competing with. If you want to keep any stats secret you can use the privacy settings on the website.

Flex: tapping for updates

The Flex is the most minimalist wristband in terms of screen info. It’s made up of a row of flashing LED dots that you activate by tapping a number of times. These indicator lights keep you up to date with your goal progress, battery charging and sleep/wake modes.

Fitbit’s larger and pricier Charge (£99) has a more versatile display, which doubles as a watch, for instance, and shows you steps, active minutes, calories burned and even floors climbed.

When you tap your Flex twice with your finger, the LED indicator lights to show how much of your goal you’ve accomplished. Each fully lit indicator represents 20 percent of your total goal. A blinking light shows the current segment of the goal you’re working on.

So, for example, two lights solid and the third blinking means you’ve achieved between 40 and 60 percent of your overall goal.

When you reach your goal, your Flex will vibrate and flash the LED indicator lights to celebrate.

To enter sleep mode, tap your Flex rapidly for one to two seconds; the Charge features auto sleep detection. Your Flex will vibrate and display two slowly dimming lights to indicate that sleep mode has begun.

When you wake up, tap your Flex rapidly for one to two seconds to exit sleep mode. Upon exiting sleep mode, your Flex will vibrate and flash all five LED indicator lights.

Fitbit Flex: battery life

The Flex should last about five days before needing a charge. Try to remember to keep it charged as it’s frustrating when you’re just about to walk or run and the battery fades out. The best time to give it a charge is while you’re asleep or sat stuck in the office, or maybe relaxing in front of the TV or reading a book.

Fitbit premium

There’s also a premium Fitbit Digital Trainer that studies your exercise and activity data to design a personalized fitness plan to make you fitter and adapts to your progress. It costs £39.99/year, and there’s a free 7-day trial.

Buying Advice

The Fitbit Flex is a cool-looking, lightweight wristband that tracks and monitors your daily activity and sleep patterns. It syncs with a desktop dashboard and mobile app to give you up-to-date activity data in gorgeous graphs. You can compete with Fitbit-using friends and even upgrade to a premium Daily Trainer service. I found the Fitbit Flex gave me added motivation to walk or run that bit further, and keep an eye on my weight and fitness activities. Its addictive and fun, and if that gets you moving more and generally fitter and leaner its better for you than most other computing or mobile devices. Also consider the next step up: the Fitbit Charge also counts floors climed, and shows you your stats right there on your wrist.