Field-based Measurement of Sleep: Agreement between Six Commercial Activity Monitors and a Validated Accelerometer

ABSTRACT

Objective

To examine agreement between multiple commercial activity monitors (CAMs) and a validated actigraph to measure sleep.

Methods

Thirty adults without sleep disorders wore an Actiwatch Spectrum (AW) and alternated wearing 6 CAMs for one 24-h period each (Fitbit Alta, Jawbone Up3, Misfit Shine 2, Polar A360, Samsung Gear Fit2, Xiaomi Mi Band 2). Total sleep time (TST) and wake after sleep onset (WASO) were compared between edited AW and unedited CAM outputs. Comparisons between AW and CAM data were made via paired t-tests, mean absolute percent error (MAPE) calculations, and intra-class correlations (ICC). Intra-model reliability was performed in 10 participants who wore a pair of each AW and CAM model.

Results

Fitbit, Jawbone, Misfit, and Xiaomi overestimated TST relative to AW (53.7–80.4 min, P ≤ .001). WASO was underestimated by Fitbit, Misfit, Samsung and Xiaomi devices (15.0–27.9 min; P ≤ .004) and overestimated by Polar (27.7 min, P ≤ .001). MAPEs ranged from 5.1% (Samsung) to 25.4% (Misfit) for TST and from 36.6% (Fitbit) to 165.1% (Polar) for WASO. TST ICCs ranged from .00 (Polar) to .92 (Samsung), while WASO ICCs ranged from .38 (Misfit) to .69 (Samsung). Differences were similar between poor sleepers (Pittsburgh Sleep Quality Index global score >5; n = 10) and good sleepers. Intra-model reliability analyses revealed minimal between-pair differences and high ICCs.

Conclusions

Agreement between CAMs and AW varied by device, with greater agreement observed for TST than WASO. While reliable, variability in agreement across CAMs with traditional actigraphy may complicate the interpretation of CAM data obtained for clinical or research purposes.

Acknowledgments

All devices evaluated in this study were purchased using laboratory funds set aside for CEK; device manufacturers had no role in the study design, reporting of results, or interpretation of results. Investigator support for CEK was provided by National Institutes of Health grant K23HL118318.

Disclosure statement

BBG has received grant support independent of this project from the American Heart Association, National Institutes of Health (NIH), and the Tomayko Foundation. DJB has received grant support independent from this project from the NIH, served as a paid consultant for the American Academy of Physician Assistants, Bayer, BeHealth, CME Institute, Ebb Therapeutics, and Emmi Solutions, and received licensing fees for the Pittsburgh Sleep Quality Index, copyrighted to the University of Pittsburgh. MHH and CEK have received grant support independent of this project from the NIH. SRP has received grant support independent of this project from the NIH, American Sleep Medicine Foundation, ResMed Foundation, Bayer Pharmaceuticals, and Philips Respironics.

Supplementary material

Supplemental data for this article can be accessed at the publisher’s website.

Additional information

Funding

This work was supported by the National Heart, Lung, and Blood Institute [K23HL118318].