Indices and Sweating Patterns for the Assessment of Heat Tolerance

Abstract

2) Ohara's sweating type method, representing a relation between local sweat rate and sodium concentration in sweat, was modified by using salt loss in place of sodium concentration. Sweating patterns were classified into U, N, and T Types in the Q' (salt loss)-V (peak sweat rate) plane. Type U corresponds to Ohara's Type 1, the least heat tolerant, and Type T corresponds to Ohara's Type 4, the most heat tolerant.3) Results obtained with the authors' method and Index I coordinated well. Type U showed the highest value of Index I, Type T the lowest which suggest that the lower value of Index I indicates a greater heat tolerance.4) The three type method and Index S revealed no significant correlation, which suggests that Index S is not a measure to be applied to heat tolerance. It was discussed that Index S may be utilized as an index to represent effectiveness of homeostatic mechanism to thermal regulation. 5) Ohara's four sweating types and Index I showed no significant correlation. Thus, the three-type method appears to be a more satisfactory tool for examining heat tolerance.As an index for determining heat adaptability, OHARA (1967) proposed

Effect of Exercise in a Hot Environment for 7 Successive Days on Physiological Responses and Heat Tolerance

“…A smaller value of B (rise in rectal temperature) after heat acclimatization might be due to increased heat dissipation by profuse sweating. A smaller value of index I indicates superior heat tolerance (Hori et al, 1974). Thus, it can be said that heat tolerance was improved at the cost of increase of strain in terms of water metabolism.…”

“…By calculation and transformation, Eq. I =a(1 + S2) 1/2 can be derived as follows (Hori et al, 1974) Thus, the value of parameter "a" runs parallel to change in sweating reaction. Mechanism of changes in physiological response to heat induced by physical training for 7 successive days might be as follows.…”

“…Tel. (0798) 45-6385 proposed a numerical index for evaluation of human heat tolerance (Hori et al, 1974 (Hori et al, 1975(Hori et al, , 1978. Mean values are given with their standard deviations.…”

Comparison of physiological responses to heat between subtropical and temperate natives.

“…Accordingly, heat tolerance of subjects in group O was superior to that of subjects in group M when heat tolerance was assessed by numerical heat tolerance index. The value of index S represents the ratio of relative rise in core temperature to relative water loss and relative salt loss and the parameter "a" represents the magnitude of strain in terms of water-electrolyte metabolism (Hori et al, 1974). Figure 1 represents I versus S plot for groups O and M. In this figure, iso-sweating lines are drawn by connecting Isosweating lines were drawn with their values of parameter.…”

“…Circles: Drawn around the means with radiuses of standard errors the points of the same value of parameter "a", A (1+C2/A2)1/2 (Hori et al,1974).…”