Prediction of mean skin temperature for use as a heat strain scale by introducing an equation for sweating efficiency

Abstract

The present paper made the heat balance equation (HBE) for nude or minimally clad subjects a linear function of mean skin temperature (t(sk)) by applying new equations for sweating efficiency (η(sw)) and thermoregulatory sweat rate (S(wR)). As the solution of the HBE, the equation predicting t(sk) was derived and used for a heat strain scale of subjects. The η(sw) was proportional to the reciprocal of S(w)/E(max) (S(w), sweat rate; E(max) maximum evaporative capacity) and the S(wR) was proportional to t(sk) with a parameter of the sweating capacity of the subject. The errors of predicted t(sk) from observations due to the approximation of η(sw) were examined based on experimental data conducted on eight young male subjects. The value of errors of t(sk) was -0.10 ± 0.42 °C (mean ± sample standard deviation (SSD)). We aim to apply the predicted t(sk) of a subject at a level of sweating capacity as a heat strain scale of a function of four environmental factors (dry- and wet-bulb temperatures, radiation, and air velocity) and three human factors (metabolic rate, sweating capacity, and clothing (≤0.2clo)).

Analysis of sweating efficiency and its effects on the heat strain alleviation of clothed subjects

“…The results obtained from Eq. () are shown in Figure 5 (Kubota et al, 2014a) and compared with the results by Alber & Holmér, Candas, and by η sw = 1 – 0.5 w sw 2 in ISO7933 (ISO7933, 1989).…”

“…As shown in Eq. (), the equation for η sw is expressed in the form (Kubota et al, 2014a)where .…”

“…() on the imaginary SE for the two‐part‐pattern was previously introduced by the present authors in Ref. (Kubota et al, 2014a) without the prior knowledge of η sw , which enabled the explicit derivation of the MST from the heat balance equation. The area of a HP / A D =0.31 for the cycle ergometer is nearly equal to the area of the “trunk and head.” Eq.…”

“…The sweating efficiency (SE), or the evaporative efficiency of sweating, is of prime importance for estimating human response to a hot environment. It is essential for assessing heat strain to estimate the amount of heat loss accurately through the evaporation of sweat (Kubota et al, 2014a, 2014b); however, it requires time‐consuming work to elucidate the SE by experiments. Until now, a limited number of experiments with human subjects have been conducted to identify the SE.…”

Influence of Internal Structure and Composition on Head’s Local Thermal Sensation and Temperature Distribution

“…A lot of studies [23][24][25] have been carried out on heat generation, heat dissipation and heat exchange with the environment of the body. Some scholars carried out the experiment with subjects, to study the heat generation and dissipation [26][27][28][29][30], and obtained the thermal response of the human body to the environment, which includes the temperature change and skin temperature distribution, as well as the subjective thermal sensation and thermal comfort state of subjects [7,11,20,29,[31][32][33][34]. However, although these experiments can obtain the human body thermal response and the subjective thermal state of the human body, few of them can obtain the heat transfer law of internal tissues, which results in the incomplete explanation of the heat transfer process in the human body.…”