Exergy efficiency on incremental stationary bicycle test: A new indicator of exercise performance?

  • Carlos Eduardo Keutenedjian MadyEmail author
  • Tatiane Lie Igarashi
  • Cyro Albuquerque
  • Paulo Roberto Santos-Silva
  • Tiago Lazzaretti Fernandes
  • Arnaldo Jose Hernandez
Technical Paper


The first and second laws of the thermodynamics were applied to the human body to evaluate the performance of subjects under different training levels. Ten cyclists were evaluated in the stationary bicycle with the indirect calorimetry analysis to obtain the metabolism on an energy and exergy basis. A distinguishing feature of this article is the evaluation of the exergy efficiency of the body with the knowledge of the real performed power and the internal temperature (measured tympanic temperature and calculated esophagus temperature). Regarding the skin temperature, an infrared camera was used to measure different parts of the body. Therefore, the phenomenological behavior of the body was assessed and used as a basis to apply the exergy analysis. Results indicate that the destroyed exergy can be an indicator of performance when compared with maximum oxygen consumption. Nevertheless, more experiments must be carried out to proper state if there is a correlation. Eventually, the exergy efficiency was calculated for all subjects, and its value was around 23 to 28%.


Stationary bicycle test Thermodynamic analysis Exergy analysis Maximum oxygen consumption Destroyed exergy Performance indexes 



The first author acknowledges FAPESP (São Paulo Research Foundation) for the Grant 2015/22883-7 and CNPQ (National Council of Scientific and Technological Development) for Grant 400401/2016-9.

Compliance with ethical standards

Conflit of interest

Authors declare that there is no conflict of interest in the publication of the present manuscript.

Informed consent

Consent to submit has been received explicitly from all co-authors, as well as from the responsible authorities—tacitly or explicitly—at the institute/organization where the work has been carried out, before the work is submitted.


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Copyright information

© The Brazilian Society of Mechanical Sciences and Engineering 2019

Authors and Affiliations

  • Carlos Eduardo Keutenedjian Mady
    • 1
    Email author
  • Tatiane Lie Igarashi
    • 2
  • Cyro Albuquerque
    • 2
  • Paulo Roberto Santos-Silva
    • 3
  • Tiago Lazzaretti Fernandes
    • 3
  • Arnaldo Jose Hernandez
    • 3
  1. 1.School of Mechanical EngineeringUniversity of CampinasCampinasBrazil
  2. 2.Department of Mechanical EngineeringCentro Universitário da FEISão Bernardo do CampoBrazil
  3. 3.Sports Medicine Group of the Department of Orthopedics and TraumatologyUniversity of São Paulo Medical SchoolSão PauloBrazil

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