JMIR Publications

ABSTRACT

Background:

Increasing use of smartwatches for physical activity monitoring raises questions about their accuracy, particularly in patients with cardiovascular and peripheral artery diseases. These patients often struggle to meet recommended activity levels.

Objective:

This study evaluates the accuracy of the Life Plus smartwatch (versions 2 and 3) designed for easy activity tracking via step counts.

Methods:

34 participants, comprising of healthy individuals (n=10), cardiovascular disease (CVD) patients (n=14), and peripheral artery disease (PAD) patients (n=10), wore 6 Life Plus watches simultaneously (3 of version 2 (V2) and 3 of version 3 (V3)), positioned on wrists, hips and ankles. Participants walked on a treadmill for 3-min sessions at speeds of 1.8, 2.5, 3.2, and 4 km/h. Actual step counts were recorded through video footage.

Results:

The V3 watch demonstrated higher accuracy. Among healthy subjects, mean percentage differences between actual steps and V3 watch steps were lower when worn at the wrist (+1.4% at 3.2 km/h and +0.54% at 4 km/h). In patient groups, differences were lower with the V3 watch worn at the wrist at slower speeds (1.8 km/h: CVD +5.84%, PAD +7.36%; 2.5 km/h: CVD +0.72%, PAD +2.24%) and at the hip at moderate speeds (3.2 km/h: CVD +3.27%, PAD +1.18%; 4 km/h: CVD -4.14%, PAD -2.61%).

Conclusions:

For optimized counting, V3 watches should be preferred, worn at the wrist for healthy individuals, worn at the wrist or hip for patients with slow walking speeds (1.8 km/h, 2.5 km/h) and worn at the hip for faster walking patients (3.2 km/h, 4 km/h). Clinical Trial: This study was approved by the ethics committee of the University Hospital of Saint-Etienne in June 2022 (reference CE 2022-36).