"Fitness trackers accurately measure heart rate but not calories burned, study finds Fitness trackers..."

“Fitness trackers accurately measure heart rate but not calories burned, study finds Fitness trackers accurately measure heart rate but not calories burned, study finds”

- https://www.sciencedaily.com/releases/2017/05/170524141812.htm

source http://physiquesportsuk.tumblr.com/post/161178074919