Research
Print page Print page
Switch language
The Capital Region of Denmark - a part of Copenhagen University Hospital
Published

Estimating physical activity and sedentary behaviour in a free-living environment: A comparative study between Fitbit Charge 2 and Actigraph GT3X

Research output: Contribution to journalJournal articleResearchpeer-review

  1. Assessment of the sublingual microcirculation with the GlycoCheck system: Reproducibility and examination conditions

    Research output: Contribution to journalJournal articleResearchpeer-review

  2. Novel functions of the luteinizing hormone/chorionic gonadotropin receptor in prostate cancer cells and patients

    Research output: Contribution to journalJournal articleResearchpeer-review

  3. Hepatitis C prevalence in Denmark in 2016-An updated estimate using multiple national registers

    Research output: Contribution to journalJournal articleResearchpeer-review

  4. Inflammation, non-endothelial dependent coronary microvascular function and diastolic function-Are they linked?

    Research output: Contribution to journalJournal articleResearchpeer-review

  1. Familial associations in hair cortisol concentration: A cross-sectional analysis based on the Healthy Start study

    Research output: Contribution to journalJournal articleResearchpeer-review

  2. Vitamin D and Calcium Milk Fortification in Pregnant Women with Periodontitis: A Feasibility Trial

    Research output: Contribution to journalJournal articleResearchpeer-review

  3. Prediction of carotid intima-media thickness and its relation to cardiovascular events in persons with type 2 diabetes

    Research output: Contribution to journalJournal articleResearchpeer-review

View graph of relations

BACKGROUND: Activity trackers such as the Fitbit Charge 2 enable users and researchers to monitor physical activity in daily life, which could be beneficial for changing behaviour. However, the accuracy of the Fitbit Charge 2 in a free-living environment is largely unknown.

OBJECTIVE: To investigate the agreement between Fitbit Charge 2 and ActiGraph GT3X for the estimation of steps, energy expenditure, time in sedentary behaviour, and light and moderate-to-vigorous physical activity under free-living conditions, and further examine to what extent placing the ActiGraph on the wrist as opposed to the hip would affect the findings.

METHODS: 41 adults (n = 10 males, n = 31 females) were asked to wear a Fitbit Charge 2 device and two ActiGraph GT3X devices (one on the hip and one on the wrist) for seven consecutive days and fill out a log of wear times. Agreement was assessed through Bland-Altman plots combined with multilevel analysis.

RESULTS: The Fitbit measured 1,492 steps/day more than the hip-worn ActiGraph (limits of agreement [LoA] = -2,250; 5,234), while for sedentary time, it measured 25 min/day less (LoA = -137; 87). Both Bland-Altman plots showed fixed bias. For time in light physical activity, the Fitbit measured 59 min/day more (LoA = -52;169). For time in moderate-to-vigorous physical activity, the Fitbit measured 31 min/day less (LoA = -132; 71) and for activity energy expenditure it measured 408 kcal/day more than the hip-worn ActiGraph (LoA = -385; 1,200). For the two latter outputs, the plots indicated proportional bias. Similar or more pronounced discrepancies, mostly in opposite direction, appeared when comparing to the wrist-worn ActiGraph.

CONCLUSION: Moderate to substantial differences between devices were found for most outputs, which could be due to differences in algorithms. Caution should be taken if replacing one device with another and when comparing results.

Original languageEnglish
JournalPLoS One
Volume15
Issue number6
Pages (from-to)e0234426
ISSN1932-6203
DOIs
Publication statusPublished - 2020

    Research areas

  • Accelerometry/instrumentation, Adult, Energy Metabolism/physiology, Exercise/physiology, Female, Fitness Trackers, Humans, Male, Middle Aged, Monitoring, Ambulatory/instrumentation, Reproducibility of Results, Sedentary Behavior

ID: 61192974