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Latest Which? fitness tracker test results reveal accuracy issues

Devices struggled with calories and heart rate

Fitness trackers

Some devices still struggle to track activity and fitness accurately

Our recent fitness tracker results revealed that some devices regularly struggle to track calories burnt, with two devices overstating the figure by 100%. One device also understated heart rate by nearly 60%.

Our tough fitness tracker and smartwatch tests put five of the latest devices through their paces, including the Apple Watch Series 1, Fitbit Charge 2 and TomTom Touch. One of the fitness trackers overstated calories burnt during walking by a whopping 105% – meaning you’ll think you’ve burnt double the number of calories that you actually have.

We know that fitness trackers can struggle to track calories burnt, but unusually one device in the latest batch consistently understated heart rate by nearly 60% during high intensity exercise – the biggest inaccuracy we’ve seen. If you’re looking to get fit or lose weight then knowing your heart rate can be important, but during high intensity exercise such a big understatement could also be risky.

It’s not all bad news, though, as we also found a Best Buy wearable device that was accurate at counting steps during walking and running, as well as tracking calorie burn and distance correctly.

Don’t end up with an inaccurate device – check out all of our Best Buy fitness trackers and Best Buy smartwatches.

Fitness tracker vs smartwatch

The difference between smartwatches and fitness trackers boils down to whether you want a wearable device that’s designed to help you communicate and deliver notifications, or one that primarily keeps track of exercise and health.

Our latest batch put fitness trackers and smartwatches to the test. To help you pick the right type of wearable for you, use the interactive tool on our should I buy a fitness tracker or smartwatch guide.

Latest wearable reviews

Click on the links below to read individual reviews of the latest phones we’ve tested. Models are listed in alphabetical order.

Apple Watch Series 1 – £269
Fitbit Charge 2 – £110
Fitbit Flex 2 – £70
TomTom Touch – £130
Xiaomi MiBand 2 – £20

Prices are correct as of 4 January 2017 and are subject to change.

More on this…

Find out how to buy the best fitness tracker

The Apple smartwatches are popular, but which Apple Watch should you buy?

We reveal the best fitness trackers of 2017

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