Wearables lack accuracy in measuring energy output

Most wearable devices are not producing accurate results for tracking energy expenditure, according to a new study published in the Journal of American Medicine Association (JAMA).

The study investigated the accuracy of energy use measurement among 12 wearables, including Fitbit, Jawbone and Garmin devices, and compared the results with metabolic chamber and doubly labeled water methods. It involved 19 healthy participants, nine men and 10 women, between 21 and 50 years old.

"The wearable devices tested were able to rank daily total energy expenditure between individuals, but absolute values differed widely among devices and varied significantly from the gold standard measures," according to the study's authors. An accurate estimation of energy expenditure is critical in determining the relationships between aspects of human behavior, physical activity, and overall health, the authors added.

One reason the devices may underestimate total energy expenditure is because users might take them off for activities such as bathing; changing the battery may also impact measurements, the authors said.

The number of U.S. consumers using wearables has doubled from 16 percent in 2014 to 33 percent as of this month. 

In addition, strong smartwatch adoption and increasing consumer awareness will cause wearables shipments to hit 110 million by year's end and pass the 200 million mark in three years. 

Grand View Research identified North America as the most mature fitness device market thanks to increasing consumer awareness, new technology and a higher spend on healthcare. 

For more information:
- here's the JAMA study