Fitness & Sleep Wearables

Wearables — wrist trackers, rings and chest straps — estimate steps, heart rate, calories and sleep stages from motion and optical sensors.

What published research reports

A systematic review of 158 validation publications in JMIR mHealth and uHealth (2020) reported that consumer wearables measure steps and heart rate with reasonable accuracy in most conditions — typically within a few percent for steps, with heart-rate error growing during high-intensity movement — while energy-expenditure (calorie) estimates were consistently inaccurate across brands, often by 30% or more. Sleep-stage estimates from wrist devices are reported in the validation literature as approximate compared with laboratory polysomnography. The review's authors conclude the devices are most reliable for tracking personal trends over time rather than exact numbers.

References

• Fuller D, et al. Reliability and Validity of Commercially Available Wearable Devices for Measuring Steps, Energy Expenditure, and Heart Rate: Systematic Review. JMIR Mhealth Uhealth. 2020;8(9):e18694. JMIR