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How to buy the best activity tracker or fitness watch

How to buy the best fitness or activity tracker

By Hannah Walsh

Article 1 of 3

Fitbit, Garmin or Misfit? How many sensors do you need, and what can you track? Our guide will help you find the best fitness or activity tracker.

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The best fitness or activity trackers can provide you with an accurate, comprehensive and easy-to-understand snapshot of your health – day after day, year after year. 

But our independent tests have also uncovered trackers that just aren’t up to the task - and there’s little point buying an imprecise, uncomfortable device that lacks the useful features you may need

There’s plenty of choice when it comes to what you want your fitness band to do, and that’s where we can help. How many types of sensors do you need? Would you be better off with a fitness watch? Should you buy a device with a screen? And is it worth paying extra for a model that can also relay texts and notifications from your phone? 

Once you know what type of fitness or activity tracker you want, find the best one for you by using our fitness watches and activity tracker reviews.

How much does a good fitness or activity tracker cost?

You can buy a tracker for less than £15, or you could pay close to £200. But our testing has shown there’s little correlation between price and accuracy. 

We've found a model costing just £20 that tracked steps with no error

It’s absolutely possible to pick up a great, affordable fitness tracker if you don’t mind missing out on some more advanced functions. We’ve found some great budget-friendly options in our tests – check out our best cheap fitness trackers for 2017.

Should I buy a device with a screen?

If you want to check exercise progress on your activity tracker, or see the time, then a screen is a must. Without one, a tracker can still monitor the steps you take, and even your heartbeat, but you’ll have to check the relevant app on your phone to see any of your stats.

Pros: With a screen on your device, it’s possible to see your progress as you exercise. Some models with larger screens will even relay text messages and other notifications directly from your phone to your wrist.

Cons: A tracker with a small screen can look rather basic and cheap. One with a larger screen, or a high-resolution screen, will be heavier, bulkier and may require more frequent charging. If you want a light tracker that you’ll hardly notice you’re wearing, then consider one with either a small LCD display or no display at all.

Which sensors do I need?

Some fitness or activity trackers have as many as 11 separate sensors, to track everything from your steps and heart rate to your exact location and even the intensity of sunlight to let you know when it’s time to reach for the sunscreen. Having a variety of accurate, consistent sensors gives you more detailed and, in some cases, more accurate, data. But, as revealed by our tough tests, not every device has accurate sensors.

And having too many sensors can reduce the battery life of your device or make it more complicated to use. We rate every device in our tests to see how easy it is to use – check out our ease-of-use ratings before you buy.

Step tracking: A pedometer is the most basic sensor, and one you’ll find in every fitness tracker. This will count your steps and can often capture distance, too, based on an estimation of your stride length. We put the step counter through its paces in our tough lab test and check the accuracy.

Built-in GPS: If your tracker has built-in GPS, it can track distance more accurately – as long as the GPS works well and doesn’t drop the connection, that is. Many fitness trackers can be paired to your mobile phone to make use of your phone’s GPS, but built-in GPS is useful if you want to jog or cycle without carrying your phone.

Heart-rate monitoring: A heart-rate monitor is another option worth considering. This, as you might expect, will measure your heart rate throughout the day. It will report on your average heart rate, and periods of peaks and troughs – useful for tracking the effect of any periods of activity. During our lab testing, we put the accuracy of heart-rate monitoring to the test to ensure they don’t miss a beat.

Calorie burn: Most trackers provide an ongoing record of your calorie burn. Models with heart-rate monitors usually loop in the heart-rate data to better estimate how many calories you’ve burned. However, the accuracy of calorie-burn data is largely dependent on how well the algorithm built in by the manufacturer interprets your fitness data. The presence of a heart-rate monitor doesn’t guarantee more accurate calorie-burn information. 

Sleep monitoring: Most trackers will keep an eye on your sleep, including motion sensing to see whether your sleep is disturbed, and a measure of REM, light and deep sleep. A smart alarm feature means your tracker will pick the optimal time in your sleep cycle, that’s close to your alarm, to wake you up.

Advanced sensors: More advanced models have specialist sensors to track everything from your oxygen consumption (VO2 Max) to barometers and lux meters for checking the relative pressure or light levels where you are. These are interesting but won’t help much in tracking your fitness. If you're looking for a device capable of advanced sports tracking, a fitness watch may be the device for you.

Is battery life important?

Using your tracker could become irritating if you find yourself needing to charge it too frequently. Models with lots of sensors, particularly heart-rate monitors or built-in GPS, and high-resolution screens will need charging more regularly. Most activity trackers have a battery life that ranges from a couple of days to a couple of weeks. Some models use coin-cell batteries, like a watch, and these will last several months before needing replacing.

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