Your fitness tracker is lying to you

By Oliver Smith 8 January 2016
Fitbit Charge HR

Wearables and fitness trackers provide key datasets to measure your well being, but what if the data is dodgy?

You might not realise it, but you’re collecting medical data about yourself every day, just by carrying a smartphone in your pocket or wearing a fitness tracker or smartwatch.

iPhones automatically measure step counts, Apple Watches take heart rate readings every 10 minutes and some fitness trackers can even measure the number of steps you climb.

All this data is fantastic, both for monitoring your own health and for doctors to get a picture of your well-being.

But, what happens when this data goes wrong?

Dodgy data

Fitbit, the maker of some of the world’s most popular fitness trackers, is being taken to court in the US for putting its users lives at risk by allegedly mis-reporting their heart-rates.

Fitbit’s Charge HR and Surge both promise that their built-in PurePulse heart rate monitors “ensure you’re pushing yourself hard enough, but not overtraining”.

However Teresa Black, along with two other claimants, is arguing that her Fitbit reported a heart-rate of 82 bpm while her personal trainer recorded this at 160 bpm.

“Plaintiff Black was approaching the maximum recommended heart rate for her age, and if she had continued to rely on her inaccurate PurePulse Tracker, she may well have exceeded it, thereby jeopardizing her health and safety,” the lawsuit claims.

“But far from ‘counting every beat’, the PurePulse Trackers do not and cannot consistently and accurately record wearer’s heart rates during the intense physical activity for which Fitbit expressly markets them.”

Fitbit said it will defend against the lawsuit.

But it’s a worry because the medical data being generated by wearables like Fitbits and even the smartphones we carry around will be used by doctors and nurses in the future (if not already) to monitor your wellbeing.

Apple has even partnered with universities around the world, including the University of Oxford, to create ResearchKit, a way for iPhone and Apple Watch users to share their step counts, heart rates and take part in medical studies.