Exergy Analysis of the Musculoskeletal System Efficiency during Aerobic and Anaerobic Activities

Spanghero, Gabriel Marques; Neto, Cyro Albuquerque; Fernandes, Tiago Lazzaretti; Hernandez, Arnaldo José; Mady, Carlos Eduardo Keutenedjian

doi:10.3390/e20020119

Cited by 16 publications

(20 citation statements)

References 44 publications

(112 reference statements)

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“…The remaining problem is the gradient of temperature between the core, and the skin which is highly accurate represented by. 15 From these measurements, it is possible to use the stationary bicycle to have the performed work 11,12 and properly evaluate the traditional models of heat and enthalpy transfer to the environment 15 which are highly validated for basal conditions. Eventually, the relations of different researchers of several fields, mechanical engineers (thermodynamic and heat and mass transfer area) and medical doctors (from sports and orthopedic field) have been increasing the relation with two areas with similar objectives, although with a completely different language.…”

Section: Results Of Previous Analyses and Future Workmentioning

confidence: 99%

“…Eventually, it was performed a comparison of two tests in which the power executed by the body is a known variable: bicycle stationary ergometric test and weightlifting 11 . Results indicated that the use of a stationary bicycle is the best option to establish a method to experimentally evaluate the thermal behavior of the human body 11 .…”

Section: Experimental Procedures and Difficultiesmentioning

confidence: 99%

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Clinical Application of Thermography for Energy Balance in Athletes – State of the Art and New Paradigms

Fernandes

Hernandez

Neto

et al. 2018

Rev Bras Med Esporte

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This article aims to describe the evolution of techniques that have enabled the proper application of the Laws of Thermodynamics for physical activity and athletes. The objective is to propose performance indicators to help add information to the current indices used in medicine and sports, such as the lactate threshold and maximum oxygen consumption. A number of analyses of the results obtained by the group were carried out for this purpose. Moreover, a discussion regarding which techniques would provide a better response to the measurements was analyzed. Some examples are the substitution of the treadmill running test with the stationary bicycle (known performed work), and a literature search in order to measure internal temperature more accurately. Level of Evidence V; Expert opinion.

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Section: Results Of Previous Analyses and Future Workmentioning

confidence: 99%

Section: Experimental Procedures and Difficultiesmentioning

confidence: 99%

Clinical Application of Thermography for Energy Balance in Athletes – State of the Art and New Paradigms

Fernandes

Hernandez

Neto

et al. 2018

Rev Bras Med Esporte

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“…In recent years, numerous studies have been published on thermodynamic analysis of processes based on metabolism in the biological systems [7][8][9][10][11][12][13][14][15][16][17][18][19]. However, in the literature, there is a limited number of studies on respiratory thermodynamics [8,10,15,19].…”

Section: Introductionmentioning

confidence: 99%

Solunum Yetmezliği Olan Hastalarda Mekanik Ventilasyon Sırasında ve Sonrasında Entropi Üretimi ve Ekserji Yıkımı

Çatak¹,

Develi²,

Bayram³

2020

European Journal of Science and Technology

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BACKGROUND: Mechanical ventilation is a useful supportive treatment for patients with respiratory failure who are not able to maintain the level of ventilation required to maintain the oxygenation and carbon dioxide elimination. Mechanical ventilation is often life-saving, but it also has risks. Thermodynamic analyses are used to test the feasibility of processes leading to a better understanding of the system's overall performance. Energy losses (entropy) and the destruction of maximum useful work (exergy) leading to reduced respiratory work of breathing efficiency, can be calculated by thermodynamic analysis of the respiratory muscles. OBJECTIVE: To determine the entropy generation, exergy destruction, and glucose consumption during and after weaning from mechanical ventilation in patients with respiratory failure by thermodynamic analysis. METHODS: In this study, a human respiratory system during and after weaning from mechanical ventilation modeled thermodynamically using the first and second laws of thermodynamics. The work of breathing data adapted from the literature. Mass and energy analyzes are carried out according to the 1st law of thermodynamics, while entropy generation is calculated according to the 2nd law of thermodynamics which enables us to measure energy losses. In this thermodynamic model, the body temperature was considered at 37 °C, and the surrounding air condition was taken at 25 °C. RESULTS: Exergy destructions during and after weaning from mechanical ventilation were calculated as 2.23x10-2 and 1.75x10-2 kJ/min, respectively. Entropy generation by the patients through the breathing cycle was 7.48x10-5 (kJ/K)/min during mechanical ventilation while 5.89x10-5 (kJ/K)/min after weaning from mechanical ventilation, respectively. The glucose consumed for work of breathing in patients during and after weaning from mechanical ventilation was calculated as 0.58-0.45 mmol/min, respectively. CONCLUSION: After weaning from mechanical ventilation, the patients have significantly decreased entropy generation, exergy destruction, and glucose consumption, indicating to the improvements in the structure of respiratory mechanics and diaphragm perfusion. The reductions in entropy generation and exergy destruction after weaning from mechanical ventilation also indicates an increase in the mechanical efficiency of the respiratory muscles. According to the results of the energy balance analysis, the decrease in muscle energy requirement, was determined and the calculations found that the patient used 1.3 times more glucose during mechanical ventilation than after weaning from mechanical ventilation for work of breathing. In this study, the thermodynamic approach was used to determine the benefit of mechanical ventilation. More powerful work and multidisciplinary data are needed to progress reliable procedures.

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“…Several Thermodynamic approaches to biological systems have been performed in the past decades. To cite some, there is the study of a single cancerous cell [ 3 ], protocols in hypothermia techniques [ 4 ], and an analysis of physical activities [ 5 , 6 , 7 ]. There is also a review article gathering these new applications as in Ozilgen [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

Exergy Analysis and Human Body Thermal Comfort Conditions: Evaluation of Different Body Compositions

Garcia

Une

Oliveira

et al. 2018

Entropy

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This article focuses on studying the effects of muscle and fat percentages on the exergy behavior of the human body under several environmental conditions. The main objective is to relate the thermal comfort indicators with exergy rates, resulting in a Second Law perspective to evaluate thermal environment. A phenomenological model is proposed of the human body with four layers: core, muscle, fat and skin. The choice of a simplified model is justified by the facility to variate the amount of mass in each tissue without knowing how it spreads around the body. After validated, the model was subjected to a set of environmental conditions and body compositions. The results obtained indicate that the area normalization (Watts per square meter) may be used as a safe generalization for the exergy transfer to environment. Moreover, the destroyed exergy itself is sufficient to evaluate the thermal sensation when the model is submitted to environmental temperatures lower than that considered for the thermal neutrality condition (and, in this text, the thermal comfort) . Nevertheless, for environments with temperatures higher than the calculated for the thermal neutrality, the combination of destroyed exergy and the rate of exergy transferred to the environment should be used to properly evaluate thermal comfort.

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Exergy Analysis of the Musculoskeletal System Efficiency during Aerobic and Anaerobic Activities

Cited by 16 publications

References 44 publications

Clinical Application of Thermography for Energy Balance in Athletes – State of the Art and New Paradigms

Clinical Application of Thermography for Energy Balance in Athletes – State of the Art and New Paradigms

Solunum Yetmezliği Olan Hastalarda Mekanik Ventilasyon Sırasında ve Sonrasında Entropi Üretimi ve Ekserji Yıkımı

Exergy Analysis and Human Body Thermal Comfort Conditions: Evaluation of Different Body Compositions

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