皮膚圧迫による発汗抑制効果に対する高度温熱負荷の影響

抄録

Takagi and his colleagues (1960) postulated that skin pressure not only inhibits sweating and various autonomic activities but also reduces central thermoregulatory activity, and that body temperature (T_b) may rise or fall depending upon the ambient temperature. On the other hand, Ogawa et al. (1979, 1981) suggested that the skin pressure may exert a sweat-inhibitory effect primarily through the interaction of sudomotor impulses at the spinal segmental level.
Presently, in an attempt to elucidate the limiting factors of the sweat-inhibitory effect of skin pressure, we examined changes in T_b, whole body sweat rate (m), local sweat rate (S), heart rate (HR), metabolic rate (M) and respiratory frequency (f) during skin pressure (5 kg/50 cm², 12 min) applied to uni- or bilateral subaxillary regions at rest in medium to severe heat (T_a : 37-50°C) and during excercise of medium to heavy loads (WL: 225-750 kpm/min) .
In general, the unilateral pressure caused depression of S on the same side of the upper half of the body, and the bilateral one induced inhibition of S over the whole upper half of the body. However, in severe thermal conditions caused either by exposure to severe heat or by heavy exercise where thermal equilibrium was not attained, the sweat-inhibitory effect of skin pressure was reduced progressively to be either transient, obscure or absent, as thermal load was increased.
These results confirm the assumption made by Ogawa et al. that skin pressure may exert a sweat-inhibitory effect under the control of the thermoregulatory central mechanism.