Fitness Trackers: Accurate, More or Less?

DALLAS, TX (KFSN) -- They track everything from how deep you sleep to how many paces you run every minute. But are all these fitness trackers honest? Are they really accurate? And, is there a difference between them? A recent study pitted four different brands against one another and against a heart monitor in a stress test. Which one was best?

Doctor Mark Millard loves accurate measurements. He's a pulmonary specialist and a triathlete. He's connected to a wireless EKG along with two wrist fitness trackers. One costs two hundred dollars, the other, four hundred dollars that's connected to a chest strap. A ten-minute track run tests both of them.

Mark Millard, MD, FCCP at Baylor University Medical Center in Dallas said "I get 155. I got you at 156. So, that's pretty close, but on my wrist sensor, it was only 125."

Resting, all of the monitors read about the same. But add movement, like riding a stationary bike, and the basic wrist monitor doesn't measure up to the wrist/chest monitor and the baseline EKG.

"The big one is 134, the wrist is 120, and the EKG says 135." Doctor Millard continued.

While cheaper fitness trackers can count steps, they're not so great measuring heart rates, according to a study in the annals of internal medicine. But they all have value.

"They get you off the couch. They get you onto the track. They get you active and that, in and of itself, pays for itself in gold. You might even get a discount on your health insurance from your company that you work for." Said Doctor Millard.

Doctor Millard thinks the pricier trackers are worth it.

"It's the best anti-depressant there is, and you sleep well." He said.

So it appears you get what you pay for.

The benefits of exercise are well documented, leading to a longer, happier life. And, exercise can reduce the likelihood of developing Alzheimer's or dementia.