UNLABELLED

Commercial self-monitoring devices are becoming increasingly popular, and over the last decade, the use of self-monitoring technology has spread widely in both consumer and medical markets. The purpose of this study was to evaluate five commercially available self-monitoring devices for further testing in clinical applications. Four activity trackers and one sleep tracker were evaluated based on step count validity and heart rate validity.

METHODS

The study enrolled 22 healthy volunteers in a walking test. Volunteers walked a 100 m track at 2 km/h and 3.5 km/h. Steps were measured by four activity trackers and compared to gyroscope readings. Two trackers were also tested on nine subjects by comparing pulse readings to Holter monitoring.

RESULTS

The lowest average systematic error in the walking tests was -0.2%, recorded on the Garmin Vivofit 2 at 3.5 km/h; the highest error was the Fitbit Charge HR at 2 km/h with an error margin of 26.8%. Comparisons of pulse measurements from the Fitbit Charge HR revealed a margin error of -3.42% ± 7.99% compared to the electrocardiogram. The Beddit sleep tracker measured a systematic error of -3.27% ± 4.60%.

CONCLUSION

The measured results revealed the current functionality and limitations of the five self-tracking devices, and point towards a need for future research in this area.