Abstract
The heat loss responses (sweating and skin blood flow responses) during exercise are very important for maintaining internal temperature. This study focuses on the characteristics of heat loss responses during exercise from a viewpoint of investigating non-thermal factors. In the mild hyperthermic condition, short-term dynamic exercise induces to show an intensity-dependent increase in sweating rate and decrease cutaneous vascular conductance (skin blood flow) without changes in thermal factors. These responses are caused by mainly non-thermal factors include central command, peripheral mechanisms activating the mechanosensitive and metabosensitive receptors in exercising muscle, baroreflex, mental stress, and so on. In case of activating mostly central command and metaboreflex from exercising muscle, these factors affect the heat loss responses during exercise by facilitating the sweating response, and inhibiting heat loss by altering cutaneous vascular conductance. On the other hand, an activation of mechanoreflex from exercising muscle only seems to influence the increase in the sweating response but not cutaneous vascular conductance. On the bases of these results, non-thermal factors associated mainly with central command, peripheral mechanisms activating the mechanosensitive and metabosensitive receptors in exercising muscle enhances the sweating response which may compensate the inhibition of heat loss by the altered skin blood flow which might play a role in maintenance of cardiovascular system during exercise. [J Physiol Sci. 2007;57 Suppl:S52]
