A Validation Study of Two Wrist Worn Wearable Devices for Remote Assessment of Exercise Capacity

We determined wearable device errors in assessing a 6-Minute Walk Test (6MWT). 16 healthy adults (male 7(44%), mean $age\pm SD \ 27\pm 4$ years) performed a standard (6MWT-S) and modified, free range’, (6MWT-FR) protocols with a Garmin and Fitbit smartwatch to measure three parameters: distance, step count and heart rate (HR). Distance during the 6MWT-FR was measured with smaller errors during 6MWT-S for both Garmin (Mean Absolute Percentage Error, $MAPE=9.8{\%}$ [4.6%,12.6%] $vs \quad 18.5\%[13.0\%,27.4\%],p < 0.001)$ and Fitbit $(M A P E=9.4 \%[4.5 \%, 13.3 \%] \ {vs } \ 22.7 \%[18.3 \%, 29.3 \%],p < 0.001)$ . Steps were measured with smaller errors with Garmin $(M A P E=2.3 \%[1.1 \%, 2.9 \%]; r=0.96)$ than Fitbit (Fitbit: $MAPE=8.1\%[5.0\%,12.9\%]; \ r=0.24)$ . Heart rate at rest, peak exercise and recovery was measured with median MAPE ranging between 1.2% and $2.9{\%}$ , with no evidence of difference between the two devices. Wearable measurements of the 6MWT provide insights about exercise capacity which could be monitored and evaluated remotely.