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Human body heat balance equation to consider core body temperature in assessment of heatstroke risk

Sakoi, Tomonori ; Kurazumi, Yoshihito ; Apriliyanthi, Sri Rahma ; Sawada, Shin ichi and Gao, Chuansi LU (2024) In Building and Environment 247.
Abstract

Increased core body temperature and dehydration are critical thermal physiological responses to heat disorders. Dehydration is preventable through adequate water intake. However, a simple heat balance equation for assessing the heatstroke risk considering the core body temperature is currently lacking. Hence, this study proposes an equation for evaluating heatstroke risk. To derive the equation, the thermal regulation of the human body and heat interactions between the body core, skin, clothing, and indoor and outdoor environments were considered. The heat flow and heat capacity were represented as water flows caused by the water head difference and cross-sectional area of the tanks, respectively. Subsequently, the importance of... (More)

Increased core body temperature and dehydration are critical thermal physiological responses to heat disorders. Dehydration is preventable through adequate water intake. However, a simple heat balance equation for assessing the heatstroke risk considering the core body temperature is currently lacking. Hence, this study proposes an equation for evaluating heatstroke risk. To derive the equation, the thermal regulation of the human body and heat interactions between the body core, skin, clothing, and indoor and outdoor environments were considered. The heat flow and heat capacity were represented as water flows caused by the water head difference and cross-sectional area of the tanks, respectively. Subsequently, the importance of considering the above elements as a unified system for designing a thermally comfortable environment and preventing heatstroke is discussed. Next, a heatstroke threshold equation is presented in the form of human body heat balance equation, which considers the core body temperature. This equation enabled us to evaluate the threshold for the combination of the environmental, clothing, and activity parameters beyond which the body temperature exceeds the acceptable limit for heatstroke. The equation was validated by comparing the thresholds with the reported upper limit of the prescriptive zone. The calculated thresholds for various parameters revealed that the parameters related to evaporative heat loss, such as clothing evaporative resistance, were the dominant parameters influencing the threshold. Although the equation can evaluate the influences of various types of activity and clothing, it can be applied only to acclimatized workers in good health with sufficient water and salt intake.

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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Core body temperature, Heatstroke, Heatstroke threshold equation, Human body heat balance equation, Occupational health, Prescriptive zone
in
Building and Environment
volume
247
article number
111020
publisher
Elsevier
external identifiers
  • scopus:85178357220
ISSN
0360-1323
DOI
10.1016/j.buildenv.2023.111020
language
English
LU publication?
yes
id
d5a6c5cf-38e9-4ee4-b78d-605ead011cc8
date added to LUP
2023-12-20 13:33:53
date last changed
2024-02-09 11:27:55
@article{d5a6c5cf-38e9-4ee4-b78d-605ead011cc8,
  abstract     = {{<p>Increased core body temperature and dehydration are critical thermal physiological responses to heat disorders. Dehydration is preventable through adequate water intake. However, a simple heat balance equation for assessing the heatstroke risk considering the core body temperature is currently lacking. Hence, this study proposes an equation for evaluating heatstroke risk. To derive the equation, the thermal regulation of the human body and heat interactions between the body core, skin, clothing, and indoor and outdoor environments were considered. The heat flow and heat capacity were represented as water flows caused by the water head difference and cross-sectional area of the tanks, respectively. Subsequently, the importance of considering the above elements as a unified system for designing a thermally comfortable environment and preventing heatstroke is discussed. Next, a heatstroke threshold equation is presented in the form of human body heat balance equation, which considers the core body temperature. This equation enabled us to evaluate the threshold for the combination of the environmental, clothing, and activity parameters beyond which the body temperature exceeds the acceptable limit for heatstroke. The equation was validated by comparing the thresholds with the reported upper limit of the prescriptive zone. The calculated thresholds for various parameters revealed that the parameters related to evaporative heat loss, such as clothing evaporative resistance, were the dominant parameters influencing the threshold. Although the equation can evaluate the influences of various types of activity and clothing, it can be applied only to acclimatized workers in good health with sufficient water and salt intake.</p>}},
  author       = {{Sakoi, Tomonori and Kurazumi, Yoshihito and Apriliyanthi, Sri Rahma and Sawada, Shin ichi and Gao, Chuansi}},
  issn         = {{0360-1323}},
  keywords     = {{Core body temperature; Heatstroke; Heatstroke threshold equation; Human body heat balance equation; Occupational health; Prescriptive zone}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Building and Environment}},
  title        = {{Human body heat balance equation to consider core body temperature in assessment of heatstroke risk}},
  url          = {{http://dx.doi.org/10.1016/j.buildenv.2023.111020}},
  doi          = {{10.1016/j.buildenv.2023.111020}},
  volume       = {{247}},
  year         = {{2024}},
}