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Biomedical Algorithms for Wearable Monitoring
Published in Christopher Siu, Krzysztof Iniewski, IoT and Low-Power Wireless, 2018
Su-Shin Ang, Miguel Hernandez-Silveira
Another means of estimating energy expenditure involves the use of motion sensors such as accelerometers. This is based on the fact that energy expenditure increases proportionally with the muscular activity responsible for acceleration and movement of the body and its extremities during physical exercise and locomotion. Recent advances of micro-engineering technologies have enabled the development of small portable and wearable devices intended for measuring physical activity. These lightweight and unobtrusive systems are equipped with accelerometers and data-logging capabilities. Therefore, they can be used in routine clinical practice, and/or at home or elsewhere in the community, i.e. where the patient carries on with his/her usual ordinary activities of daily living. Many of these devices are available in the market, and are described in various studies and comparative reviews [30, 31]. Unfortunately, there are some biomechanical disadvantages impeding the sole use of accelerometers for energy expenditure assessment, as follows.
Effects of Environmental Conditions on Performance in winter sports
Published in Youlian Hong, Routledge Handbook of Ergonomics in Sport and Exercise, 2013
Whereas hot environments in summer add to the heat load arising from exercise, cold temperatures in winter time favour heat dissipation. Consequently, maintaining the balance between heat production and heat loss will be easier during exercise in winter. When the production of heat exceeds heat loss, body temperature rises, resulting in hyperthermia and when heat loss exceeds heat production the body temperature drops, causing hypothermia. Intense physical activity increases the energy expenditure by 10–20 times over resting condition and at least 75 per cent is degraded as heat. Without effective heat dissipation, even moderate exercise intensity would increase body temperature by ~ 1°C every 5–6 minutes (Nimmo, 2004). Beside ambient temperature, wind, humidity and radiant energy determine environmental or climatic heat stress. The overall effect of theses factors can be assessed by the Wet Bulb Globe Temperature (WBGT). Evaporation is the most effective mechanism to dissipate body heat, contributing about 80 per cent to total heat loss and to avoid the development of hyperthermia. One litre of sweat removes 580 kcal from the body. In contrast, the amount of metabolic heat production (e.g. due to shivering or exercise) is crucial at cold environmental temperature for the maintenance of body temperature and protecting from hypothermia.
Business Improvement through Innovation in Construction Firms: The ‘Excellence’ Approach
Published in Ben Obinero Uwakweh, Issam A. Minkarah, 10th Symposium Construction Innovation and Global Competitiveness, 2002
Herbert S. Robinson, Patricia M. carrillo, Chimay J. Anumba, Ahmed M. Al-Ghassan
The idea behind indirect calorimetry is quite simple. Since oxygen is used and carbon dioxide is produced during energy-yielding reactions, exhaled air contains less oxygen and more carbon dioxide than inhaled air. The difference in composition between inspired and expired air volumes reflects the body’s release of energy through aerobic metabolic reactions. Research has shown that for every liter of oxygen consumed, 4.83 kilocalories of energy, on average, are produced. Thus, by measuring the rate of oxygen consumption before, during, and after performance of physical activities, the total energy expended by a human can be estimated. It should be noted that the conversion multiplier varies slightly depending on a physiological attribute termed the “Respiratory Quotient”. This method of estimating energy expenditure from oxygen uptake is referred to as “indirect calorimetry”. Compared to direct calorimetry, indirect calorimetry provides a reasonably accurate, portable, and relatively inexpensive method of measuring energy expenditure.
Why Do People Abandon Activity Trackers? The Role of User Diversity in Discontinued Use
Published in International Journal of Human–Computer Interaction, 2023
Christiane Attig, Thomas Franke
Finally, low trust in tracker measurement was strongly linked to abandonment due to data inaccuracy/uselessness and permanence of abandonment, suggesting a chain of causation from perceived inaccuracy to tracking attrition. Studies focusing on evaluation of objective measurement accuracy highlight the varying accuracy of tracker data types (e.g., step count, heart rate, energy expenditure; Alinia et al., 2017; Fuller et al., 2020; Beagle et al., 2020). Less clear is how users actually use measurement data to support their goal achievement and the extent to which inaccurate data prevents them from achieving their goals. For instance, it is conceivable that individuals with the external goal of losing body weight may use the indicated energy expenditure to adjust their intake of food calories. However, if the energy consumption is systematically overestimated by the tracker (as it is the case with Apple and Polar devices; Fuller et al., 2020), then the food energy supplied might also be too high to achieve the targeted weight reduction. Transparency regarding the accuracy of tracked data is essential (Yang et al., 2015) so that such a user does not falsely attribute the non-attainment of the target to their own failure. This could be realized by presenting a notice to the user if data could not be tracked correctly (e.g., because the sensors did not capture the data during an activity). To best support users in achieving their health goals, the complex interplay between data accuracy, trust, transparency, and tracking motivation needs more scientific consideration.
Impact of wildland firefighting on arterial stiffness and cardiorespiratory fitness
Published in Archives of Environmental & Occupational Health, 2022
Zachary Zeigler, Joe Sol, Payton Greer, Laura Verduzco
Prior research on seasonal effects of WLFF and body fat changes is conflicting.10,14 Our study found no changes in body mass or body fat percentage following a WLFF season. Few differences between prior studies and the current one exists that could partially explain this discrepancy. First, body composition assessment methods differ between studies with DEXA, hydrostatic weighing, and hydrodensitometry all being described. Additionally, the geographical region of WLFF is vastly different from Alaska, Montana, and Arizona being reported in the literature. Different geographic areas with accompanied environmental demands may differentially impact energy expenditure and, subsequently, body composition. Lastly, differences in dietary intake and total energy expenditure between squads and fire seasons could account for these differences. It should also be noted that the average WLFF in the current study reported 1713 h worked over six months. Thus, the average WLFF in this study worked roughly 70 h per week. It is rather remarkable that no changes took place in body weight or body fat percentage. WLFF's more than likely increased total caloric and fat consumption to offset the added energy expenditure from long work hours.
Bi-directional prospective associations between sedentary time, physical activity and adiposity in 10-year old Norwegian children
Published in Journal of Sports Sciences, 2021
Turid Skrede, Eivind Aadland, Sigmund Alfred Anderssen, Geir Kåre Resaland, Ulf Ekelund
Overweight and obesity among children is an unfavourable condition that adversely affects almost every organ system (Daniels, 2009) and increases the risk of early-onset cardiovascular disease and type 2 diabetes (Maffeis & Tato, 2001). Reasons for overweight and obesity in children include a complex mix of social, cultural, genetic, and behavioural factors (Ebbeling et al., 2002). At a fundamental level, however, weight gain occurs when energy intake exceeds energy expenditure over time (Lee et al., 2010). Physical activity (PA) increases energy expenditure and is acknowledged as an important modifiable factor for preventing weight gain (Han et al., 2010). Cross-sectional studies report that increasing time spent in moderate-to-vigorous PA (MVPA) not only reduces the risk of obesity (Katzmarzyk et al., 2015; Mitchell et al., 2017) but also is inversely associated with cardiometabolic risk factors (Renninger et al., 2020). On the other hand, time spent in sedentary behaviours is strongly associated with weight gain (Ekelund et al., 2006; Mitchell et al., 2013), suggesting that sedentary time is a risk factor for children’s health (Saunders et al., 2014).