How Accurate Is Your Wearable?

Wrist worn fitness trackers are popular with active adults, but how do they compare to old school heart monitors secured with a chest strap? Research presented at the American College of Cardiology's 66th Annual Scientific Session put 5 popular wrist worn fitness trackers to the heart rate monitoring test.
 
Fifty male and female volunteers with an average age of 38 wore a fitness tracker on each wrist or forearm along with EKG and heart rate chest monitors while exercising on a treadmill, stationary bike and elliptical machine for 18 minutes.
 
The heart rate monitor worn across the chest closely matched EKG results. The error range of wrist worn devices was plus or minus 15 to 34 beats per minute. Wearable technology was most accurate on a treadmill at low exercise intensity. Most were inaccurate when exercising on an elliptical machine at high intensity.