Cited by 76Sleep and related disordersNon-Invasive Vital Sign MonitoringContext-Aware Activity Recognition Systems

Accuracy of Fitbit Wristbands in Measuring Sleep Stage Transitions and the Effect of User-Specific Factors

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Liang, Zilu, Chapa-Martell, Mario Alberto·2019·JMIR mHealth and uHealth

Published version of a preprint

Abstract

BACKGROUND: It has become possible for the new generation of consumer wristbands to classify sleep stages based on multisensory data. Several studies have validated the accuracy of one of the latest models, that is, Fitbit Charge 2, in measuring polysomnographic parameters, including total sleep time, wake time, sleep efficiency (SE), and the ratio of each sleep stage. Nevertheless, its accuracy in measuring sleep stage transitions remains unknown. OBJECTIVE: This study aimed to examine the accuracy of Fitbit Charge 2 in measuring transition probabilities among wake, light sleep, deep sleep, and rapid eye movement (REM) sleep under free-living conditions. The secondary goal was to investigate the effect of user-specific factors, including demographic information and sleep pattern on measurement accuracy. METHODS: A Fitbit Charge 2 and a medical device were used concurrently to measure a whole night's sleep in participants' homes. Sleep stage transition probabilities were derived from sleep hypnograms. Measurement errors were obtained by comparing the data obtained by Fitbit with those obtained by the medical device. Paired 2-tailed t test and Bland-Altman plots were used to examine the agreement of Fitbit to the medical device. Wilcoxon signed-rank test was performed to investigate the effect of user-specific factors. RESULTS: Sleep data were collected from 23 participants. Sleep stage transition probabilities measured by Fitbit Charge 2 significantly deviated from those measured by the medical device, except for the transition probability from deep sleep to wake, from light sleep to REM sleep, and the probability of staying in REM sleep. Bland-Altman plots demonstrated that systematic bias ranged from 0% to 60%. Fitbit had the tendency of overestimating the probability of staying in a sleep stage while underestimating the probability of transiting to another stage. SE>90% (P=.047) was associated with significant increase in measurement error. Pittsburgh sleep quality index (PSQI)<5 and wake after sleep onset (WASO)<30 min could be associated to significantly decreased or increased errors, depending on the outcome sleep metrics. CONCLUSIONS: Our analysis shows that Fitbit Charge 2 underestimated sleep stage transition dynamics compared with the medical device. Device accuracy may be significantly affected by perceived sleep quality (PSQI), WASO, and SE.

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Authors
Liang, Z., & Chapa-Martell, M. A.
Affiliations
The University of Tokyo (JP)
Corresponding author
Liang, Zilu
Venue
JMIR mHealth and uHealth
Published
2019-06-06
Volume
7
Issue
6
Pages
e13384
ISSN
2291-5222 (ISSN-L)
OpenAlex
W2940755444
Cited by
76
References
64
Citations by year
2026: 9 · 2025: 2 · 2024: 10 · 2023: 12 · 2022: 13 · 2021: 13 · 2020: 12 · 2019: 4 · 2018: 1
FWCI
12.38
Type
journal article
Language
en
Open access
Licence
cc-by
Locations
  • JMIR mhealth and uhealth (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
Japan Society for the Promotion of Science (16H07469, 19K20141)
Topics
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Sleep and related disorders
  • Physical Sciences › Engineering › Biomedical Engineering › Non-Invasive Vital Sign Monitoring
  • Physical Sciences › Computer Science › Computer Vision and Pattern Recognition › Context-Aware Activity Recognition Systems
Keywords
sleep stage transitions, wearable devices, sleep stage classification, measurement accuracy, polysomnography, sleep efficiency, wake after sleep onset, Pittsburgh Sleep Quality Index
MeSH terms
Wearable Electronic Devices, Adult, Female, Humans, Japan, Male, Surveys and Questionnaires, Sleep Stages, Weights and Measures, Reproducibility of Results, Polysomnography

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