Fitness Trackers. There are so many of them on the market now as the health and fitness industry is still riding the crescent of a wave. But a new study published this week in the Journal of Personalised Medicine, from a team of Stanford researchers states that there is a much higher margin for error than perhaps the majority had thought.
The study looked at the accuracy and reliability of 7 of the most popular trackers on the market; the Apple Watch, Basis Peak, Fitbit Surge, Microsoft Band, Mio Alpha 2, PulseOn, and Samsung Gear S2.
60 participants were asked to wear the fitness trackers and were monitored while sitting, running, walking and cycling, whilst being simultaneously assessed via telemetry and indirect calorimetry.
The results were quite shocking.
‘Don’t rely on fitness trackers to track number of calories burned.’ The Register 26 May 2017
‘Why your personal fitness tracker may not be all that accurate.‘ Consumer Affairs 25 May 2017
‘Fitness tracker fail: Research shows devices off by as much as 93 per cent when counting calories’ National Post 25 May 2017
I have always been very cautious over recommending fitness trackers to clients or anybody who asks my opinion, especially when it comes down to relying on them for how many calories you have burnt. But even I was shocked to read that when tested, the margin for error for calories burnt was between 24-90%!!! That is a whopping difference, especially for those people who use them to ‘eat back their calories.’
An acceptable error range would be 5%, so even 24% (which was the Fitbit Surge) is very high.
The study stated that the devices ‘adequately’ tested average heart rate, but there was still margin for error beyond what you might expect.
In my personal experience (I do not own one but some clients do), I think they are great for encouraging you to get more active, to strive towards the recommended 10,000 steps per day, to remind you to get up and move if you have been sitting for too long. However I have never liked the calories burnt aspect of them, and usually disregard what they say and tell clients not to use it as an excuse to eat more.
Somebody checks their fitness tracker at the end of the day and discover that they have burnt 1200 calories that day, when in actual fact they have only burnt 900. They may have an extra piece of cake or a glass of beer since they think they have done well that day and met their target. Overtime though this adds up, that is an extra 2100 calories every week which the user thinks they have ‘deserved’. If your goal is losing fat then this is could certainly be counterproductive.
SO SHOULD WE JUST THROW FITNESS TRACKERS AWAY?
Hold your horses.
I am not saying fitness trackers are useless and should be resigned to your top drawer. I am just suggesting that you start using them with a little bit more caution. Track your steps, make sure you are being active. If you like seeing what calories you have burnt, great, but don’t use it as your tracking for food. Use it in conjunction with other measurements and look at trends over time.
Do you own a fitness tracker? What has been your experience with one?
Love Abi xxxx
Ps Have you read my April favourites blog yet? Click here.