Influences of overall thermal balance on local inputs for drive of evaporation in men

Abstract

Three kinds of experiments were carried out in a climatic chamber: experiments with warm load on the whole body at 36 degrees C (4 subjects); experiments at 36 degrees C with reduction of thermal load (28 degrees C) on the left leg (right leg at 36 degrees C) (8 subjects); and experiments at 36 degrees C with antisymmetric thermal load on the legs of 44 degrees C (right leg) and 28 degrees C (left leg), which resulted in additional thermal loads of +/- 30 W/leg (8 subjects). The additional thermal loads, which were applied via two climatic boxes, produced measurable effects on sweat rate when applied to one leg only. In comparison to the experiment 1, experiment 2 brought about a significant reduction of local evaporation on the left leg. With antisymmetric thermal loads on both legs (experiment 3), which did not influence the overall thermal balance, there was no significant influence on local evaporation, although significant changes of local temperatures were measured. It is suggested that the well-known regulatory models, declaring local, mean skin, and core temperatures as local evaporation drive should be supplemented with an important additional feature: local control of evaporation by local skin temperature may be blocked by an overall thermal balance.

Human sudomotor responses to heating and cooling upper‐body skin surfaces: cutaneous thermal sensitivity

“…While the present design does not permit an evaluation of the mechanisms underlying this hypothesis, the current data are not consistent with such observations, with alterations in sweat output occurring in all regions simultaneously, with each region being affected by about the same extent, regardless of the skin region being treated. Similar trends have been observed by Heising & Werner (1987), Werner & Heising (1990) and Bothorel et al . (1991).…”

Development of an empirical model of human sweating and a semi-empirical model of human thermoregulation

“…Hertman (1952) found the sweat rate increased linearly above 34 °C. Heising (1987) investigated the interaction between core and peripheral control and introduced the idea that an overall thermal balance actually had an overriding effect on thermoregulatory control. In experiments performed in the dry desert heat, no correlation was found between the skin and core temperature during exercise with water and salt replenishment (Dill et al 1973).…”