Sleep and Breathing

, Volume 20, Issue 2, pp 853–854 | Cite as

Fitbit Flex: an unreliable device for longitudinal sleep measures in a non-clinical population

  • Argelinda Baroni
  • Jean-Marie Bruzzese
  • Christina A. Di Bartolo
  • Jess P. Shatkin
Pediatrics • Letter to the Editors

Dear Editor,

Clinicians and researchers are increasingly interested in employing tracking devices to measure activity and sleep, both of which are calculated via algorithms that use accelerometer data [1]. While polysomnography (PSG) is viewed as the gold standard for assessing sleep, it is costly, time-intensive, and intrusive. Actigraphy is often preferred in situations for which PSG is not indicated, such as naturalistic conditions or for prolonged observations—days to weeks. However, actigraphs are relatively expensive as well, making them unsuitable to monitor large samples. As such, activity-tracking devices have been proposed as an alternative. Several recent reports, including one by Montgomery-Downs [2] published in this journal, suggest that consumer-level devices might offer a valid and reliable alternative, as they are easy to use and relatively low in cost [2, 3, 4]. We are writing this letter to report our disappointing experience with Fitbit Flex to measure sleep in a...


College Student Sleep Mode Sleep Parameter Baseline Data Collection Online Video 
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Conflict of interest

Drs. Baroni and Bruzzese and Ms. Di Bartolo have no conflicts of interest to declare. Dr. Shatkin receives royalties for publication from W.W. Norton & Company.


  1. 1.
    Lee J, Finkelstein J (2015) Consumer sleep tracking devices: a critical review. Stud Health Technol Inform 210:458–460PubMedGoogle Scholar
  2. 2.
    Montgomery-Downs HE, Insana SP, Bond JA (2012) Movement toward a novel activity monitoring device. Sleep Breath 16:913–917CrossRefPubMedGoogle Scholar
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    Diaz KM et al (2015) Fitbit(R): an accurate and reliable device for wireless physical activity tracking. Int J Cardiol 185:138–140CrossRefPubMedPubMedCentralGoogle Scholar
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    Tully MA et al (2014) The validation of Fitbit Zip physical activity monitor as a measure of free-living physical activity. BMC Res Notes 7:952CrossRefPubMedPubMedCentralGoogle Scholar
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    Lillehei AS et al (2015) Effect of inhaled lavender and sleep hygiene on self-reported sleep issues: a randomized controlled trial. J Altern Complement Med 21:430–438CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Argelinda Baroni
    • 1
  • Jean-Marie Bruzzese
    • 1
  • Christina A. Di Bartolo
    • 1
  • Jess P. Shatkin
    • 1
  1. 1.The Child Study Center at NYU Langone Medical CenterNew YorkUSA

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