Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2016 Nov 29;3(2):2055102916679012.
doi: 10.1177/2055102916679012. eCollection 2016 Jul.

A practical validation study of a commercial accelerometer using good and poor sleepers

David L Dickinson  1   2   3 , Joseph Cazier  1 , Thomas Cech  4
Affiliations

A practical validation study of a commercial accelerometer using good and poor sleepers

David L Dickinson et al. Health Psychol Open. .

Abstract

We validated a Fitbit sleep tracking device against typical research-use actigraphy across four nights on 38 young adults. Fitbit devices overestimated sleep and were less sensitive to differences compared to the Actiwatch, but nevertheless captured 88 (poor sleepers) to 98 percent (good sleepers) of Actiwatch estimated sleep time changes. Bland-Altman analysis shows that the average difference between device measurements can be sizable. We therefore do not recommend the Fitbit device when accurate point estimates are important. However, when qualitative impacts are of interest (e.g. the effect of an intervention), then the Fitbit device should at least correctly identify the effect's sign.

Keywords: Fitbit; actigraphy; longitudinal studies; sleep; validation studies.

PubMed Disclaimer

Conflict of interest statement

Declaration of conflicting interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Figures

Figure 1.
Figure 1.
Fitbit versus actigraphy (ordinary least squares line fit shown).
Figure 2.
Figure 2.
Fitbit scored versus raw nightly TST data compared to actigraphy (ordinary least squares line fit shown). Left panel of Figure 2 reproduces the left panel of Figure 1 with axis rescaled for comparability with raw Fitbit data.
Figure 3.
Figure 3.
Bland–Altman plots—total sleep time (TST). 95 percent confidence interval shown.
Figure 4.
Figure 4.
Bland–Altman plots—efficiency (device-scored). 95 percent confidence interval shown.
Figure 5.
Figure 5.
Bland–Altman plots—quasi-efficiency (TST/TIB). 95 percent confidence interval shown.
Figure 6.
Figure 6.
Fitbit–Actiwatch longitudinal TST device differences.
Figure 7.
Figure 7.
Fitbit–Actiwatch longitudinal device-measured sleep efficiency differences.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Bland MJ, Altman DG. (1986) Statistical methods for assessing agreement between two methods of clinical measurement. The Lancet 327(8476): 307–310. - PubMed
    1. Buysse DJ, Reynolds CF, III, Monk TH, et al. (1989) The Pittsburgh Sleep Quality Index: A new instrument for psychiatric practice and research. Psychiatry Research 28(2): 193–213. - PubMed
    1. De Zambotti M, Claudatos S, Inkelis S, et al. (2015) Evaluation of a consumer fitness-tracking device to assess sleep in adults. Chronobiology International 32(7): 1024–1028. - PMC - PubMed
    1. Evenson KR, Goto MM, Furberg RD. (2015) Systematic review of the validity and reliability of consumer-wearable activity trackers. International Journal of Behavioral Nutrition and Physical Activity 12(1): 1–22. - PMC - PubMed
    1. Goldman SE, Stone KL, Ancoli-Israel S, et al. (2007) Poor sleep is associated with poorer physical performance and greater functional limitations in older women. Sleep 30(10): 1317–1324. - PMC - PubMed

LinkOut - more resources