Validity and reliability of Fitbit activity monitors compared to ActiGraph GT3X+ with female adults in a free-living environment.

OBJECTIVES Inexpensive activity monitors have recently gained popularity with the general public. Researchers have evaluated these consumer-based monitors in laboratory-conditions. Given the current wide-spread consumer use of these devices, it is important to ensure users are attaining accurate information compared to previously validated measures. This study investigates the accuracy of Fitbit One and Flex activity monitors in measuring steps, sedentary time, and time spent in light, moderate, and vigorous intensity activities with ActiGraph GT3X+ with female adults in free-living conditions. DESIGN Cross-sectional study. METHODS Twenty-two women, 21.23±1.63 years, BMI: 22.35±2.34kg/m2 wore two Fitbit Ones (bra and waist), one Fitbit Flex on the wrist, and one ActiGraph GT3X+ on the waist for seven-consecutive days. Repeated measures ANOVA was used to explore differences in steps, sedentary time, and time spent in light, moderate and vigorous intensity activities among the four devices. RESULTS No differences were found in number of steps recorded across the four devices. Fitbit One, waist and bra, overestimated time spent in light intensity activities. Fitbit One (waist) and Fitbit Flex overestimated time spent in moderate intensity activities. Fitbit One, waist and bra, and Fitbit Flex overestimated time spent in vigorous intensity activities. All Fitbit activity monitors overestimated MVPA and underestimated sedentary time compared to the ActiGraph. CONCLUSIONS Regardless of wear-location all Fitbit devices provide similar activity monitoring and users can wear the devices wherever best accommodates their lifestyle or needs. Users should not rely solely on these monitors when tracking vigorous and MVPA activities.

[1]  L. Mâsse,et al.  Physical activity in the United States measured by accelerometer. , 2008, Medicine and science in sports and exercise.

[2]  Edward McAuley,et al.  Predicting long-term maintenance of physical activity in older adults. , 2003, Preventive medicine.

[3]  Gregory J Welk,et al.  Validity of consumer-based physical activity monitors. , 2014, Medicine and science in sports and exercise.

[4]  S. Fowler,et al.  Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. , 2002 .

[5]  C. Tudor-Locke,et al.  How Many Steps/Day Are Enough? , 2004, Sports medicine.

[6]  Gregory J Welk,et al.  Comparison of Consumer and Research Monitors under Semistructured Settings. , 2016, Medicine and science in sports and exercise.

[7]  J. Tucker,et al.  Physical activity in U.S.: adults compliance with the Physical Activity Guidelines for Americans. , 2011, American journal of preventive medicine.

[8]  S. Blair,et al.  Sedentary behaviors increase risk of cardiovascular disease mortality in men. , 2010, Medicine and science in sports and exercise.

[9]  Guy Faulkner,et al.  Is this Bit Fit? Measuring the Quality of the Fitbit Step-Counter , 2012 .

[10]  M. Hamilton,et al.  Validity of GT3X and Actiheart to estimate sedentary time and breaks using ActivPAL as the reference in free-living conditions. , 2015, Gait & posture.

[11]  T. Wadden,et al.  Effects of lifestyle activity vs structured aerobic exercise in obese women: a randomized trial. , 1999, JAMA.

[12]  Barry I Graubard,et al.  Association of self-reported sleep duration with eating behaviors of American adults: NHANES 2005-2010. , 2014, The American journal of clinical nutrition.

[13]  C. Matthews,et al.  Too much sitting: the population health science of sedentary behavior. , 2010, Exercise and sport sciences reviews.

[14]  Matthew P Buman,et al.  Twenty-four Hours of Sleep, Sedentary Behavior, and Physical Activity with Nine Wearable Devices. , 2016, Medicine and science in sports and exercise.

[15]  J. Schwartz,et al.  Abstract MP11: Fitbit: An Accurate and Reliable Device for Wireless Physical Activity Tracking , 2015 .

[16]  M. Tremblay,et al.  A comparison of direct versus self-report measures for assessing physical activity in adults: a systematic review , 2008, The international journal of behavioral nutrition and physical activity.

[17]  C. Caspersen,et al.  Physical activity and the incidence of coronary heart disease. , 1987, Annual review of public health.

[18]  Jing Wang,et al.  Effect of adherence to self-monitoring of diet and physical activity on weight loss in a technology-supported behavioral intervention , 2012, Patient preference and adherence.

[19]  J. Shaw,et al.  Objectively Measured Sedentary Time, Physical Activity, and Metabolic Risk , 2007, Diabetes Care.

[20]  J. Shaw,et al.  Breaks in Sedentary Time , 2008, Diabetes Care.

[21]  J. Takács,et al.  Validation of the Fitbit One activity monitor device during treadmill walking. , 2014, Journal of science and medicine in sport.

[22]  Dinesh John,et al.  Validation and comparison of ActiGraph activity monitors. , 2011, Journal of science and medicine in sport.

[23]  L. Cadmus-Bertram,et al.  Use of the Fitbit to Measure Adherence to a Physical Activity Intervention Among Overweight or Obese, Postmenopausal Women: Self-Monitoring Trajectory During 16 Weeks , 2015, JMIR mHealth and uHealth.