Smart watches, activity monitors and fitness trackers abound and are fun and informative gadgets to help track daily physical activity. You undoubtedly know more than one person who actively is counting their daily steps.
Current fitness trackers record activity in terms of the number of steps per day. The recommendation for 150 minutes of physical activity per week is generally consistent with activity monitor studies suggesting step counts of 7,000 to 8,000 per day. As activity monitors become more sophisticated and less expensive, there's growing interest in using them as a source of data on daily physical activity.
In a study conducted at the University of Pittsburgh, researchers identified the limitations of current commercial activity monitors in both step counting accuracy and usability features for older adults. Led by Andrea L. Hergenroeder, the study evaluated the accuracy of seven commercial activity monitors in measuring steps in older adults with varying walking abilities. Forty-three participants (age = 87 ± 5.7 years) completed a gait speed assessment while wearing the activity monitors. The Accusplit AX2710 Accelerometer Pedometer had the highest accuracy (93.68% ± 13.95%), whereas the Fitbit Charge had the lowest (39.12% ± 40.3%). Device accuracy varied based on assistive device use, and none of the monitors were accurate at gait speeds <0.08 m/s. Barriers to monitor usability included inability to apply the monitor or find the step display.
When fitness trackers overestimate exercise, people who need more exercise to maintain or lose weight might get too little activity, increasing their risk for obesity and other chronic health problems. At the same time, trackers that underestimate activity might lead some people to overdo it and put too much stress on their cardiovascular system.
Journal of Aging and Physical Activity Volume 27, Issue 2, April 2019
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