The researchers measured performance at rest, while the wearer was walking and jogging on a treadmill. Participants’ heart rates were recorded at three minutes and then 30, 60 and 90 seconds’ recovery. The study was published online in JAMA Cardiology.
“We found variable accuracy among wrist-worn HR monitors; none achieved the accuracy of a chest strap-based monitor,” the authors wrote. “In general, accuracy of wrist-worn monitors was best at rest and diminished with exercise.”