Fitness monitors are growing in popularity as people who want to get in better shape seek ways to track their physical activity. Now, researchers at Iowa State University have released a study about the accuracy of those devices.
Greg Welk is a professor of kinesiology at ISU. “Most of the monitors are released with little or no evidence of validity. Internally, they may do some checking and make sure that their calorie estimates are okay, but none of that is ever been reported or published,” Welk said.
The ISU study tested eight different activity monitors and found the BodyMedia FIT device was the top performer with a 9.3 percent error rating. “The BodyMedia FIT was the one that performed the best, but the other monitors performed fairly well,” Welk said.
The accuracy of the eight monitors, generally worn on the wrist, were tested against a portable metabolic system. “That’s the true gold standard measure,” Welk said. “We basically computed the energy expenditure estimates from all of the devices using their software and compared to the metabolic (system).”
The ISU research is published in the journal Medicine & Science in Sports & Exercise. This summer, Welk plans to test more activity monitors that recently arrived on the market.”A lot of these monitors are now very attractive to people because they integrate with their cell phone and allow connection to social media,” Welk said. Most of the devices range in price between $100 and $200.