Effect of local cooling on sweating rate and cold sensation

Abstract

Subjects resting in a 39 degrees C environment were stimulated in different skin regions with a water cooled thermode. This local cooling produced decreases in sweating rate measured at the thigh and increases in magnitude estimates of the cold sensation. The are of cold stimulation varied from 111 cm2 to 384 cm2. Sensitivity coefficients of the changes in sweating rate and magnitude estimate were corrected for differences in size of the area of stimulation and change in skin temperature and were normalized to the responses of the chest. The normalized coefficients showed the following relative sensitivities for changes in sweat rate and magnitude estimate respectively: forehead 3.3, 2.2; back 1.2, 1.4; lower leg 1.1, 0.9; chest 1.0, 1.0; thigh 0.9, 1.0; abdomen 0.8, 0.8. Varying the area stimulated from 122 cm2 to 384 cm2 produced greater changes in the sweating response than in the magnitude estimate. Rate of skin cooling during the period of stimulation had more effect on the sweating response than on the magnitude estimate. We conclude that cooling different body regions produces generally equivalent changes in the sweat rate and sensation, with the forehead showing a much greater sensitivity per unit area and temperature decrease than other areas.

Heat Exposure Control Using Non-refrigerated Water in Brazilian Steel Factory Workers

“…Literature evidence on the reduction of sweat loss of the forehead by skin cooling 15) could explain our findings with regard to the decrease in sweat loss perception. Technically, we were not able to measure this parameter objectively, due to the intervention based on water pouring on the head and for safety reasons.…”

“…Regarding head cooling 12,13) , the previous studies were performed in controlled conditions such as climatic chambers, or wearing cooling devices amidst performance comparisons 14) . In a study performed by Crawshaw et al in 1975, evidence indicated that the forehead would be one of the most sensitive places in the body to reduce sweat loss through skin cooling 15) . Thus, we hypothesized that the simultaneous washing of hands and head using 2 l of non-refrigerated water would be effective as a cooling method for workers.…”

UTCI-Fiala multi-node model of human heat transfer and temperature regulation

“…The distribution coefficients for sweating and vasodilation were obtained from Stolwijk (1971). The coefficients used in the UTCI-Fiala model to distribute the overall shivering and vasoconstriction responses were estimated from simulations of cold and extreme-cold exposures (Fiala et al 2001), while the skin sensitivity coefficients were obtained from Nadel et al (1973) and Crawshaw et al (1975).…”

Thermal sensation and comfort models for non-uniform and transient environments, part III: Whole-body sensation and comfort

“…body-segment cooling or heating b. thermal sensation scale c. thermal comfort scale The tests were designed to force local skin temperatures through a range of values. 19 body segments were tested 1 . The entire surface of a body segment was cooled or heated by using a sleeve of conditioned air that enclosed the segment (the head sleeve is shown in Figure 1a).…”

“…The differences may depend on many factors: how the body's local thermoregulatory mechanisms respond to the body's overall thermal state, asymmetry in clothing insulation and environment conditions around the body, the rate of change in the body's skin and core temperatures, and on the thermal sensitivity of the different parts involved. Although the thermosensitivity of individual body parts has been investigated in the past (e.g., [1,2]), there have been no studies of how people integrate the sensations from all their body parts when judging their whole-body thermal sensation.…”