Fitness trackers put through their paces
Fitness trackers can monitor the wearer's activity 24/7 - every footstep, mile walked, calorie burned and even the amount of sleep they are getting.
But how accurate is the data from the devices?
BBC Click's Lara Lewington wore four of the best-known trackers, (Garmin Vivosmart, Fitbit Charge, Misfit Shine and Jawbone Up Move) to see if they came up with the same results - but discovered they gave different readings.
The manufacturers say the differences are in part due to the lack of a standardised algorithm and the important measure for users is the trend - showing they are taking more steps and increasing their calorie burn over time.
10 Feb 2015