About

Fitbits are an increasingly common activity tracking device in the consumer health space, and can be integrated into Qolty to look at key features such as steps, calories burned (estimation), sleep cycles, and activity levels. The data is plotted over time and can be exported to excel down to 10 second intervals. Multiple models of Fitbit also can be integrated into Qolty. For a review of the use of Fitbit in various clinical populations, see the documentation below.

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Pricing

Monthly

$ 5

Per Patient/Month
  • 3 Years data storage past end of collection date
  • Unlimited sampling intervals during collection period.

1 Year

$ 4.75

Per Patient/Month
  • 5% Discount
  • 3 Years data storage past end of collection date
  • Unlimited sampling intervals during collection period.

3 Years

$ 4.00

Per Patient/Month
  • 20% Discount
  • 3 Years data storage past end of collection date
  • Unlimited sampling intervals during collection period.

Documentation

Introduction

Fitbit is one of the most common physical activity trackers in the consumer market.

The Fitbit company started providing activity trackers in 2008. There are several types of activity trackers, which you can wear on the wrist, or clip to the pocket, waist or bra. These trackers contain a triaxial accelerometer, an altimeter (in some new models), heart rate tracker, and global positioning system (GPS). These trackers process data collected automatically along with the information provided by the user and can estimate physical activity, calories burned, steps taken, distance covered and even the quality of sleep. Additionally, novel features such as setting goals, creating networks with friends and family, posting to social media sites and displaying presentations of data using a smartphone or computer are also in use (Rosenberg, Kadokura, Bouldin, Miyawaki, Higano & Hartzler, 2016). Day level data is available to the consumer, and minute-level data can be obtained and set at intervals of 1, 5, 10, 15, 20, or 60 min. The Fitbit device is available in a variety of shapes and sizes.

All health care providers agree on the fact that physical activity promotes wellbeing among their patients (Hébert, Caughy & Shuval, 2012). Until recently, assessment of physical activity was self-reported, but nowadays many high-tech devices like wearable activity trackers have been developed to evaluate the quality of patient’s life. Activity trackers can be used not only in the consumer market but also in research studies. Many studies related to physical activity are using activity trackers for measurement, goal-setting, self-monitoring and reinforcement (Evenson, Goto, & Furberg, 2015).

Disease Related Studies with Fitbit

Chronic obstructive pulmonary disease (COPD)

Physical activity is crucial in patients with COPD. However, it is difficult for most COPD patients to meet the recommended amount of physical activity. Because of the high-cost of pulmonary rehabilitation programs, other methods of support could be considered to help patients with COPD to enhance their physical activity. Vooijs et al. 2014 evaluated the validity and usability of the low-cost Internet-connected accelerometer, the Fitbit Ultra. They inferred that Fitbit Ultra has good validity and usability properties to monitor physical activity in patients with COPD. Additionally, patients did not express or experience any negative or unpleasant feelings wearing the device during the study, implying that this device can be used for long periods as self-management tool of physical activity.

Prostate cancer

Some of the most common side effects derived from the treatment among men with prostate cancer are the decreased bone mineral density, loss of muscle mass and strength, increased fat mass, enhanced cholesterol level, and glucose intolerance. These side effects could be reversed or limited by regular physical activity. However, men with prostate cancer usually have lower physical activity compared to the general population of elderly men. The Fitbit Zip device was also employed to evaluate the effects of physical activity in patients suffering from prostate cancer (Rosenberg et al.  2016). Patients were advised to wear the device for one baseline week followed by the filling of a brief baseline survey. After this phase, participants were given the Fitbit to keep and use for two optional weeks. Over 90% of the participants reported that the Fitbit Zip was easy to wear. These findings show that wearable activity trackers like Fitbit are highly acceptable, comfortable and easy to wear. On top of that, over 1/2 of participants continued using the Fitbit during the optional two-week phase.

The patients with prostate cancer experienced difficulties like health-related limitations, problems related to the process of syncing devices and data inaccuracies. Specifically, some participants reported that the Fitbit was not helpful because they were unable to comply with the challenges of healthy activity due to extreme pain and injuries. Furthermore, fatigue and poor stamina also limited the participants’ ability to exercise. Some concerns were raised regarding the accuracy of the step count and other forms of physical activity that are not captured by the studied devices. These technological barriers discouraged some patients from using the device, proving that these devices need familiarity with technology (Rosenberg et al. 2016).

Lung cancer patients

It is widely known that lung cancer patients’ experience diminished activity levels with time and treatment. However, physical activity can improve symptom burden, exercise tolerance, and quality of life among lung cancer patients. Thus, researchers realized the importance of investigating the feasibility of monitoring step count in advanced lung cancer and the potential correlations between physical activity and quality of life. They conducted a study among 39 patients with advanced-stage lung cancer. The physical activity was tracked with the aid of Fitbit ZIP. The daily step count, quality of life, dyspnea, and depression scores were determined during the study. The study inferred that physical activity monitored through Fitbit Zip is feasible in advanced-stage lung cancer patients. Among the participants who used the device, higher step count correlated with higher quality of life as well as lower dyspnea, pain, and depression scores (Bade et al. 2016).

Patients with cardiac disease

Cardiac disease could not be excluded from the range of applications of Fitbit. Thus, the Fitbit Zip device was used in healthy adults during treadmill walking and in patients with the cardiac disease while hospitalized at home. The study participants were twenty healthy adults who wore Fitbit devices while walking on a treadmill at different speeds and 24 patients with cardiac disease who wore a device for 24 hours during hospitalization and for 4 weeks after that at home. Measurements agreed that a speed of 3.6 km/hour or higher is required to expect acceptable accuracy in step measurement using the Fitbit device on a treadmill and in real life. Slow speeds lead to inaccuracies, and this might be a problem for patients with cardiac disease who usually walk at a slow pace (Thorup et al. 2017).

Attention Deficit Hyperactivity Disorder (ADHD)

Attention Deficit Hyperactivity Disorder is known to improve with physical activity in both the cognitive performance and executive function domains. The low acceptability and discontinuation of treatment among children raised the need for an innovative intervention incorporating the wearable activity tracker such as Fitbit Flex to enhance physical activity among adolescents with ADHD. In this intervention, the adolescents participated in a 4-week trial utilizing the Fitbit Flex in conjunction with three activities: weekly personalized step count goals, Facebook group support and daily text messages about physical activity. Results have shown that the Fitbit and Facebook intervention was feasible and had high acceptability among adolescents with ADHD, while adherence with wearing the Fitbit was high (Schoenfelder et al. 2017).

Comparisons

Blarigan et al. 2017 probed the validity of the Fitbit One’s measures of physical activity over 7 days against the gold-standard ActiGraph GT3X+ accelerometer. Additionally, they compared the devices mentioned above with the HJ-322U Tri-axis USB Omron pedometer and a physical activity diary. Among the included devices, Fitbit One’s activity and step measurements were well correlated with the ActiGraph GT3X+ and Omron pedometer. On the other hand, the Fitbit One measured two times more moderate-to-vigorous physical activity (minutes/day) on average compared with the ActiGraph. Current evidence suggests that postdiagnosis and physical activity may improve clinical outcomes in prostate cancer patients.

Lee et al. 2017 compared Fitbit Charge HR with actigraphy (Actiwatch 2) for sleep evaluation and circadian rest-activity rhythm measurement. For the comparison between the two devices, the sleep variables used were sleep start time and sleep duration and the activity variable compared included circadian rest-activity rhythm. The results revealed that the sleep start times determined by the Fitbit Charge HR and Actiwatch 2 did not significantly differ. Though, the Fitbit Charge HR tended to overestimate sleep duration for each day compared with the Actiwatch 2. Previous findings have shown a tendency for the Fitbit Charge HR to overestimate sleep duration by 20–30 min compared with the Actiwatch 2. It was due to the different mechanisms used by the two devices for the detection and calculation of sleep duration.

Furthermore, the two devices showed some differences in the activity scores.  According to the findings of this study, the Fitbit Charge HR is a reliable, valid and alternative device to use for sleep evaluations and circadian rest-activity rhythm measurements compared with Actiwatch 2, but the sensitivity of the Fitbit Charge HR was not that accurate for identifying activity as the latter.

Specificity Analysis of Five Physical Activity Monitors

The great number of physical activity trackers increased the demand for specificity among these devices, resulting to related studies. In one related study, participants had to wear the five activity trackers in activities like taking a bus journey, deskwork, taking an elevator, automobile driving, washing and drying dishes, indoor and outdoor cycling and others. Each task was carried out for either a specific duration of time or over a specific distance. The activity trackers used in this study were: Jawbone UP, ActivPAL micro, NL-2000pedometer, Withings Smart Activity Monitor Tracker (Pulse O2) and Fitbit One.  All activity monitors registered a significant number of false positive steps per minute during one or more of the prescribed activities.

The Fitbit tracker was found to be specific during the deskwork and elevator ride activities. However, the Fitbit One registered a significant number of false positives during the bus journey and on automobile driving.  On the other hand, the Fitbit One was found to be specific during the moderate non-stepping activities of washing and drying dishes and during the functional reaching task, correctly registering zero false positives. The Withings activity tracker was the one that performed best regarding specificity during the activities of daily living tested (O’Connell, ÓLaighin & Quinlan,2017).

Cosmin

Reliability

  • Excellent reliability (ICC= 0.99) when the ‘steps taken’ variable is under consideration. The energy expenditure (cal.) variable is also reliable with the mean ICC of 0.96 (Diaz et al. 2015).
  • Ferguson et al. 2015 validated that ‘steps taken’ variable was reliable with the mean ICC score of 0.95, whereas the energy expenditure (cal.) variable was fair with the mean ICC score of 0.55.
  • Excellent reliability (ICC= 0.98) when the ‘steps taken’ variable is under consideration. The energy expenditure (cal.) variable is also reliable with the mean ICC of 0.95 (Takacs et al. 2013).

Validity

  • Excellent criterion validity with the ‘steps taken’ variable; Spearman coefficient of ≥ 0.97. The energy expenditure (cal.) variable showed good criterion validity with the spearman coefficient of ≥ 0.86 (Diaz et al. 2015).
  • Lee et al. 2014 only demonstrated the criterion validity for energy expenditure; Spearmen coefficient 0.81.
  • Takacs et al. 2013 only studied the criterion validity for steps taken; excellent criterion validity with Spearmen coefficient of ≥ 0.97
  • Excellent criterion validity with the ‘steps taken’ variable; Spearman coefficient of 0.99. On the contrary, the energy expenditure (cal.) variable showed adequate criterion validity with the spearman coefficient of 0.76 (Ferguson et al. 2015).

Strengths

An increasing number of studies use activity trackers such as the Fitbit to promote physical activity among inactive populations. These trackers can also be used by health care providers to monitor patient prognosis and recovery by tracking activity levels and mobility. Furthermore, these trackers can also be used as a problem-solving tools to open new avenues in the field of medical research. Studies have shown that the validity and reliability of the data provided by the Fitbit depend on the population that uses these devices and the type of activity performed.

It has been validated that Fitbit One worn on the ankle maintained accuracy in individuals who walked more slowly and with shorter strides but other devices were less accurate in these individuals (Treacy et al. 2017).

The applicability of data obtained from a wearable activity tracker such as Fitbit Charge HR in medical research is of great importance. Compared with other actigraphy devices, these are more accessible because of their low cost.

Limitations

The specificity of the Fitbit tracker is a serious limitation. The Fitbit One registered a significant number of false positives during the bus journey and on automobile driving.  On the other hand, the Fitbit One was found to be specific during the moderate non-stepping activities of washing and drying dishes and during the functional reaching task, correctly registering zero false positives (O’Connell, ÓLaighin & Quinlan,2017).

In some cases, Fitbit One overestimated energy expenditure estimations of single speeds. Price et al. 2016 implied that such devices are not suitable as research measurement tools for recording precise and accurate energy expenditure estimates but may be suitable for use in interventions of behavior. Contrary to the above findings, a previous study demonstrated that the Fitbit One and Fitbit Flex trackers reasonably and reliably estimate step counts and energy expenditure during walking and running.  (Diaz et al., 2015).

The findings demonstrate that reliability and validity of activity trackers such as Fitbit depend on walking speed and activity trackers perform better at an average and vigorous walking speed than at a slower walking speed (Fokkema et al. 2017).

References

Bade, B., Brooks, M., Nietert, S., Ulmer, A., Thomas, D., & Nietert, P. et al. (2016). Assessing the Correlation Between Physical Activity and Quality of Life in Advanced Lung Cancer. Integr Cancer Ther. http://dx.doi.org/10.1177/1534735416684016

Blarigan, E., Kenfield, S., Tantum, L., Cadmus-Bertram, L., Carroll, P., & Chan, J. (2017). The Fitbit One Physical Activity Tracker in Men With Prostate Cancer: Validation Study. JMIR Cancer, 3(1).

Chu, A., Ng, S., Paknezhad, M., Gauterin, A., Koh, D., Brown, M., & Müller-Riemenschneider, F. (2017). Comparison of wrist-worn Fitbit Flex and waist-worn ActiGraph for measuring steps in free-living adults. PLOS ONE, 12(2), e0172535. http://dx.doi.org/10.1371/journal.pone.0172535

Diaz, K., Krupka, D., Chang, M., Peacock, J., Ma, Y., & Goldsmith, J. et al. (2015). Fitbit®: An accurate and reliable device for wireless physical activity tracking. International Journal Of Cardiology, 185, 138-140. http://dx.doi.org/10.1016/j.ijcard.2015.03.038

Evenson, K., Goto, M., & Furberg, R. (2015). Systematic review of the validity and reliability of consumer-wearable activity trackers. International Journal Of Behavioral Nutrition And Physical Activity, 12(1). http://dx.doi.org/10.1186/s12966-015-0314-1

FOKKEMA, T., KOOIMAN, T., KRIJNEN, W., VAN DER SCHANS, C., & DE GROOT, M. (2017). Reliability and Validity of Ten Consumer Activity Trackers Depend on Walking Speed. Medicine & Science In Sports & Exercise, 49(4), 793-800. http://dx.doi.org/10.1249/mss.0000000000001146

Hébert, E., Caughy, M., & Shuval, K. (2012). Primary care providers’ perceptions of physical activity counselling in a clinical setting: a systematic review. British Journal Of Sports Medicine, 46(9), 625-631. http://dx.doi.org/10.1136/bjsports-2011-090734

Lee, H., Lee, H., Moon, J., Lee, T., Kim, M., & In, H. et al. (2017). Comparison of Wearable Activity Tracker with Actigraphy for Sleep Evaluation and Circadian Rest-Activity Rhythm Measurement in Healthy Young Adults. Psychiatry Investigation, 14(2), 179. http://dx.doi.org/10.4306/pi.2017.14.2.179

O’Connell, S., ÓLaighin, G., & Quinlan, L. (2017). When a Step Is Not a Step! Specificity Analysis of Five Physical Activity Monitors. PLOS ONE, 12(1), e0169616. http://dx.doi.org/10.1371/journal.pone.0169616

Price, K., Bird, S., Lythgo, N., Raj, I., Wong, J., & Lynch, C. (2016). Validation of the Fitbit One, Garmin Vivofit and Jawbone UP activity tracker in estimation of energy expenditure during treadmill walking and running. Journal Of Medical Engineering & Technology, 41(3), 208-215. http://dx.doi.org/10.1080/03091902.2016.1253795

Rosenberg, D., Kadokura, E., Bouldin, E., Miyawaki, C., Higano, C., & Hartzler, A. (2016). Acceptability of Fitbit for physical activity tracking within clinical care among men with prostate cancer. AMIA Annu Symp Proc., 1050–1059. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5333209/

Schoenfelder, E., Moreno, M., Wilner, M., Whitlock, K., & Mendoza, J. (2017). Piloting a mobile health intervention to increase physical activity for adolescents with ADHD. Preventive Medicine Reports, 6, 210-213. http://dx.doi.org/10.1016/j.pmedr.2017.03.003

Thorup, C., Andreasen, J., Sørensen, E., Grønkjær, M., Dinesen, B., & Hansen, J. (2017). Accuracy of a step counter during treadmill and daily life walking by healthy adults and patients with cardiac disease. BMJ Open, 7(3), e011742. http://dx.doi.org/10.1136/bmjopen-2016-011742

Treacy, D., Hassett, L., Schurr, K., Chagpar, S., Paul, S., & Sherrington, C. (2017). Validity of Different Activity Monitors to Count Steps in an Inpatient Rehabilitation Setting. Physical Therapy. http://dx.doi.org/10.1093/ptj/pzx010

Vooijs, M., Alpay, L., Snoeck-Stroband, J., Beerthuizen, T., Siemonsma, P., & Abbink, J. et al. (2014). Validity and Usability of Low-Cost Accelerometers for Internet-Based Self-Monitoring of Physical Activity in Patients With Chronic Obstructive Pulmonary Disease. Interactive Journal Of Medical Research, 3(4), e14. http://dx.doi.org/10.2196/ijmr.3056

Lee JM, Kim Y, Welk GJ. (2014). Validity of consumer-based physical activity monitors. Med Sci Sports Exerc. 46(9):1840-8. doi: 10.1249/MSS.0000000000000287.

Takacs J, Pollock CL, Guenther JR, Bahar M, Napier C, Hunt MA. (2014). Validation of the Fitbit One activity monitor device during treadmill walking. J Sci Med Sport. 17(5):496-500. doi: 10.1016/j.jsams.2013.10.241.

Ferguson T, Rowlands AV, Olds T, Maher C. (2015). The validity of consumer-level, activity monitors in healthy adults worn in free-living conditions: a cross-sectional study. Int J Behav Nutr Phys Act. 12:42. doi: 10.1186/s12966-015-0201-9.