Fitness bands undervalue exercise by up to 40 per cent: study

Fitness freaks, take note! Popular wrist-worn tracking bands may underestimate exercise levels by up to 40 per cent, a new study has found.
Researchers from the University of Queensland (UQ) in Australia determined the accuracy of several popular wrist-worn fitness monitors.
"None of the devices proved to be consistently more accurate overall and the percentage error for energy expenditure was between nine and 43 per cent. Measurement of heart rate was more accurate, with only minor variances," said Matthew Wallen from UQ's School of Human Movement and Nutrition Sciences.
"Combining these two factors, it shows there are limits to how much trust we can place in such devices to monitor energy balance and, therefore, to serve as weight loss aids," said Wallen.

Testing for the study involved 22 healthy volunteers (even split of males and females) completing a variety of activities - ranging from running, cycling and walking, to seated and laying rest - for a period of approximately one hour.
The measurements of the wrist-worn devices were compared to electrocardiography readings every 15 seconds and against a portable gas analysis system which measured the number of calories burnt.

As per manufacturer instructions, each of the wrist-worn devices was individualised to reflect the user's age, gender, height and weight.
Researchers found that wrist-worn fitness monitors underestimated energy expenditure with variances of more than 40 per cent.

The findings were published in the journal PLOS One.