342 research outputs found

    A review of activity trackers for senior citizens: research perspectives, commercial landscape and the role of the insurance industry

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    The objective assessment of physical activity levels through wearable inertial-based motion detectors for the automatic, continuous and long-term monitoring of people in free-living environments is a well-known research area in the literature. However, their application to older adults can present particular constraints. This paper reviews the adoption of wearable devices in senior citizens by describing various researches for monitoring physical activity indicators, such as energy expenditure, posture transitions, activity classification, fall detection and prediction, gait and balance analysis, also by adopting consumer-grade fitness trackers with the associated limitations regarding acceptability. This review also describes and compares existing commercial products encompassing activity trackers tailored for older adults, thus providing a comprehensive outlook of the status of commercially available motion tracking systems. Finally, the impact of wearable devices on life and health insurance companies, with a description of the potential benefits for the industry and the wearables market, was analyzed as an example of the potential emerging market drivers for such technology in the future

    Wearable Technology Devices: Heart Rate and Step Count Analysis

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    The overarching purpose of this dissertation was to evaluate and analyze heart rate and/or step count measurements for six popular wearable technology devices: the Samsung Gear 2, FitBit Surge, Polar A360, Garmin Vivosmart HR+, Leaf Health Tracker, and the Scosche Rhythm+ in four separate conditions: free motion walking, free motion jogging, treadmill walking, and treadmill jogging. The four studies presented here utilized one test design and data collection protocol in which many measurements could be addressed simultaneously. Currently, there is no accepted standardized protocol to evaluate wearable technology devices. The test design utilized for this research series was introduced as a potential foundation for the establishment of a common procedure. There were three purposes for the first study in this series of four research projects. First, this study looked at whether the tested devices that recorded heart rate were reliable and valid in each of the four stated conditions. Only the Garmin Vivosmart HR+ and the Scosche Rhythm+ were significantly acceptable for all four conditions. Secondly, while all the tested devices used photoplethysmography to record heart rate, this technique has not been thoroughly validated for this purpose. Limited research indicates that devices that use this method as a measurement technique and are worn on the forearm are more accurate than those worn elsewhere on the body. Results from our study supported this conclusion. The Scosche Rhythm+, being a fore arm worn device, did produce more significantly acceptable results than the wrist worn Garmin Vivosmart HR+. Third, a standardized heart rate testing protocol has been introduced by the Consumer Technology Association. However, their recommended measurement criteria (a measurement every 1-5 seconds which would require special software to record) can be viewed as financially prohibitive, restrictive, and over compensating. The protocol used in our research presented evidence that ours, which used an average of several minutes of heart rate values, was easier to implement and did not required a financial investment to perform. The second study had two purposes. First, this study looked at whether the tested devices that recorded step count were reliable and valid in each of the four conditions. Only the FitBit Surge, Garmin Vivosmart HR+ and the Leaf Health Tracker were significantly acceptable for all four conditions. Secondly, the Consumer Technology Association has recommended a standardized step count protocol which would require the videotaping of an activity with separate tape reviews by two persons at a future time. This protocol is not feasible in certain conditions such as outside testing. Additionally, both reviewers would need to produce the exact same step count. Our testing used two manual counters where the mean of the two were used as the criterion measure. We provided strong evidence that this is an acceptable criterion measure for step counting that does not require additional time or resources. The third study compared heart rate and step count values measured by the tested devices between the different conditions. Measurements taken during free motion walking were compared to treadmill walking and those taken during free motion jogging were compared to treadmill jogging. It is generally believed that most wearable technology device companies perform device testing on a treadmill in a laboratory. Our conclusion was that there was no significant interaction or main effects for walking heart rate value comparisons. Jogging heart rate values saw significant main effects from both the environment and between the devices. Walking step count values had a significant interaction between the devices and the environment. Jogging step count values had a significant main effect between the devices. When utilizing wearable technology devices for the measurement of heart rate during walking or jogging, the Garmin Vivosmart HR+ and Rhythm Scosche Rhythm+ provided acceptable measures both in the laboratory as well as in a free motion environment. The FitBit Surge, Garmin Vivo Smart HR+, and the Leaf Health Tracker produced similar results for step count. The fourth study evaluated whether there was a correlation between both body composition percentages and body mass index values and the percent error calculated between a manual step count and that recorded by the wearable technology devices. Our results gave evidence that there are no significant correlations between body mass index and the calculated percent error. For body composition, only two conditions for the wrist worn devices had a positive significant correlation; the Samsung Gear 2 when free motion walking and the Garmin Vivosmart HR+ when free motion walking. The waist worn Leaf Activity Tracker had positive significant correlations for both treadmill walking and treadmill jogging. Even though our study produced four conditions with significant correlations, all were low to moderate in value

    Validity evaluation of the Fitbit Charge2 and the Garmin vivosmart HR+ in free-living environments in an older adult cohort

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    Background: Few studies have investigated the validity of mainstream wrist-based activity trackers in healthy older adults in real life, as opposed to laboratory settings. Objective: This study explored the performance of two wrist-worn trackers (Fitbit Charge 2 and Garmin vivosmart HR+) in estimating steps, energy expenditure, moderate-to-vigorous physical activity (MVPA) levels, and sleep parameters (total sleep time [TST] and wake after sleep onset [WASO]) against gold-standard technologies in a cohort of healthy older adults in a free-living environment. Methods: Overall, 20 participants (>65 years) took part in the study. The devices were worn by the participants for 24 hours, and the results were compared against validated technology (ActiGraph and New-Lifestyles NL-2000i). Mean error, mean percentage error (MPE), mean absolute percentage error (MAPE), intraclass correlation (ICC), and Bland-Altman plots were computed for all the parameters considered. Results: For step counting, all trackers were highly correlated with one another (ICCs>0.89). Although the Fitbit tended to overcount steps (MPE=12.36%), the Garmin and ActiGraph undercounted (MPE 9.36% and 11.53%, respectively). The Garmin had poor ICC values when energy expenditure was compared against the criterion. The Fitbit had moderate-to-good ICCs in comparison to the other activity trackers, and showed the best results (MAPE=12.25%), although it underestimated calories burned. For MVPA levels estimation, the wristband trackers were highly correlated (ICC=0.96); however, they were moderately correlated against the criterion and they overestimated MVPA activity minutes. For the sleep parameters, the ICCs were poor for all cases, except when comparing the Fitbit with the criterion, which showed moderate agreement. The TST was slightly overestimated with the Fitbit, although it provided good results with an average MAPE equal to 10.13%. Conversely, WASO estimation was poorer and was overestimated by the Fitbit but underestimated by the Garmin. Again, the Fitbit was the most accurate, with an average MAPE of 49.7%. Conclusions: The tested well-known devices could be adopted to estimate steps, energy expenditure, and sleep duration with an acceptable level of accuracy in the population of interest, although clinicians should be cautious in considering other parameters for clinical and research purposes

    Occupational physical activity in sedentary and active workers

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    2017 Spring.Includes bibliographical references.With the increasing use of technology in the workplace, many jobs are becoming more sedentary. The purpose of this study was to establish a quantitative baseline measure of occupational physical activity (OPA) in active and sedentary workers. Two activity trackers (Fitbit Charge HR™ and Hexoskin) were used to assess activity measures (step count, heart rate and energy expenditure) among workers during their work shift. The first objective of the study was to assess the agreement between two types of accelerometer-based activity trackers as measures of OPA. The second objective of this study was to assess differences in measures of OPA among workers in physically active and sedentary work environments. There was a statistically significant difference in measures of total step counts between the two devices. When comparing active and sedentary workers there were also statistically significant differences in measures of step counts, mean percent heart rate increase, maximum heart rate range and energy expenditure. Conclusion: The Fitbit Charge HR™ and Hexoskin had significant differences in measures of step counts and heart rate. When comparing active and sedentary workers, there were significant differences in measures of step counts, mean heart rate, maximum heart rate range required by job, and energy expenditure. The results of the present study provide quantitative evidence that active workers require greater physiologic demands than sedentary workers

    Accuracy of consumer-level and research-grade activity trackers in ambulatory settings in older adults

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    Wrist-worn activity trackers have experienced a tremendous growth lately and studies on the accuracy of mainstream trackers used by older adults are needed. This study explores the performance of six trackers (Fitbit Charge2, Garmin VivoSmart HR+, Philips Health Watch, Withings Pulse Ox, ActiGraph GT9X-BT, Omron HJ-72OITC) for estimating: steps, travelled distance, and heart-rate measurements for a cohort of older adults. Eighteen older adults completed a structured protocol involving walking tasks, simulated household activities, and sedentary activities. Less standardized activities were also included, such as: dusting, using a walking aid, or playing cards, in order to simulate real-life scenarios. Wrist-mounted and chest/waist-mounted devices were used. Gold-standards included treadmill, ECG-based chest strap, direct observation or video recording according to the activity and parameter. Every tracker showed a decreasing accuracy with slower walking speed, which resulted in a significant step under-counting. A large mean absolute percentage error (MAPE) was found for every monitor at slower walking speeds with the lowest reported MAPE at 2 km/h being 7.78%, increasing to 20.88% at 1.5 km/h, and 44.53% at 1 km/h. During household activities, the MAPE climbing up/down-stairs ranged from 8.38–19.3% and 10.06–19.01% (dominant and non-dominant arm), respectively. Waist-worn devices showed a more uniform performance. However, unstructured activities (e.g. dusting, playing cards), and using a walking aid represent a challenge for all wrist-worn trackers as evidenced by large MAPE (> 57.66% for dusting, > 67.32% when using a walking aid). Poor performance in travelled distance estimation was also evident during walking at low speeds and climbing up/down-stairs (MAPE > 71.44% and > 48.3%, respectively). Regarding heart-rate measurement, there was no significant difference (p-values > 0.05) in accuracy between trackers placed on the dominant or non-dominant arm. Concordant with existing literature, while the mean error was limited (between -3.57 bpm and 4.21 bpm), a single heart-rate measurement could be underestimated up to 30 beats-per-minute. This study showed a number of limitations of consumer-level wrist-based activity trackers for older adults. Therefore caution is required when used, in healthcare or in research settings, to measure activity in older adults

    Highly accurate step counting at variouswalking states using low-cost inertial measurement unit support indoor positioning system

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    © 2018 by the authors. Licensee MDPI, Basel, Switzerland. Accurate step counting is essential for indoor positioning, health monitoring systems, and other indoor positioning services. There are several publications and commercial applications in step counting. Nevertheless, over-counting, under-counting, and false walking problems are still encountered in these methods. In this paper, we propose to develop a highly accurate step counting method to solve these limitations by proposing four features: Minimal peak distance, minimal peak prominence, dynamic thresholding, and vibration elimination, and these features are adaptive with the user’s states. Our proposed features are combined with periodicity and similarity features to solve false walking problem. The proposed method shows a significant improvement of 99.42% and 96.47% of the average of accuracy in free walking and false walking problems, respectively, on our datasets. Furthermore, our proposed method also achieves the average accuracy of 97.04% on public datasets and better accuracy in comparison with three commercial step counting applications: Pedometer and Weight Loss Coach installed on Lenovo P780, Health apps in iPhone 5s (iOS 10.3.3), and S-health in Samsung Galaxy S5 (Android 6.01)

    Measuring Physical Activity Using Triaxial Wrist Worn Polar Activity Trackers: A Systematic Review

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    International Journal of Exercise Science 13(4): 438-454, 2020. Collecting objective physical activity data from research participants are increasingly done using consumer-based activity trackers. Several validation studies of Polar devices are conducted to date, but no systematic review of the current level of accuracy for these devices exist. The aim of this study is therefore to investigate the accuracy of current wrist-worn Polar devices that equips a triaxial accelerometer to measure physical activity. We conducted a systematic review by searching six databases for validation studies on modern Polar activity trackers. Studies were grouped and examined by tested outcome, i.e. energy expenditure, physical activity intensity, and steps. We summarized and reported relevant metrics from each study. The initial search resulted in 157 studies, out of which fourteen studies were included in the final review. Energy expenditure was reviewed in seven studies, physical activity intensity was reviewed in four studies, and steps was reviewed in 11 studies. There is a large difference in study protocols with conflicting results between the identified studies. However, for energy expenditure there is some indication that Polar devices perform better in free-living, compared to lab-based studies. In addition, step counting seems to have less average error compared to energy expenditure and physical activity intensity. There is large heterogeneity between the identified studies, both in terms of study protocols and results, and the accuracy of Polar devices remains unclear. More studies are needed for more recently developed devices, and future studies should take care to follow guidelines for assessment of wearable sensors designed for physical activity monitoring

    Validity of Step Counting Methods over One Day in a Free-Living Environment

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    This thesis was designed in two parts to determine the step count accuracy of activity monitors in a free-living environment. The aims of the first and second part of the study were to (1) critically evaluate the effects on step counts using the study methodology of wearing multiple monitors on the same area of the body and to (2) determine the step count accuracy of numerous consumer- and research-grade activity monitors worn on various locations of the body across all hours of a day in a free-living environment, respectively. For both parts of the study, the same hip- and wrist-worn monitor brands were examined. Wrist monitors included the ActiGraph GT9X (GT9X), Fitbit Alta (FA), Garmin Vivofit 3 (GV), and Apple Watch Series 2 (ApW). Hip monitors included the ActiGraph GT9X (GT9X), Fitbit Zip (FZ), Omron HJ-325 (OM), Yamax Digiwalker SW-200 (YX). In the second part of the study, a thigh-worn monitor, activPAL (AP), was also examined
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