Thermal Influence on Palmar Sweating and Mental Influence on Generalized Sweating in Man

Abstract

Sweat rates on the forearm and on the palm were simultaneously recorded by resistance hygrometry and the mode of sweating in these areas in response to thermal and non-thermal stimuli were compared with each other. In Series A, periodic infrared irradiation (1min on, 1min off) was done to the back of the trunk, and reflex responses in sweat rate were recorded on both test areas. A high correlation was noted between the mean changes in the palmar sweat rate and those in the forearm one during the irradiation cycle in a majority of cases. However the magnitude of the sweat response was much less on the palm than on the forearm. These observations reveal that the central mechanism of palmar sweating may be affected to some extent by the thermoregulatory mechanism.

Sweating response to passive stretch of the calf muscle during activation of forearm muscle metaboreceptors in heated humans

“…It is known that mental stress can induce sweating responses even in nonglabrous skin (28,33), and it was demonstrated recently that both thermal and psychologenic sweating may share a common descending pathway in the brain stem (11). Therefore, the potential influence of mental stress on nonglabrous sweating during passive stretches could not be eliminated in the present study, although the passive calf muscle stretches did not increase the ⌬SR palm , which may be sensitive to mental stress.…”

Modulation of the thermoregulatory sweating response to mild hyperthermia during activation of the muscle metaboreflex in humans

“…Mean skin temperature ( -Tsk) was calculated according to the method of Hardy & Dubois (1938). The SR on the three body sites was measured continuously by the ventilated capsule method (Van Beaumont & Bullard, 1963;Nadel et al 1971;Ogawa, 1975;Yamazaki et al 1994;Kondo et al 1998). Dry nitrogen gas was supplied to three capsules (chest and forearm: 7·06 cmÂ; palm: 1·53 cmÂ) at a rate of 1·5 l min¢ and the humidity of the nitrogen gas flowing out of the capsules was measured using a capacitance hygrometer (HMP 133Y; Vaisala, Finland).…”

“…However, there is no actual evidence that the sweating response is modulated during activation of the muscle metaboreflex in hyperthermia (when sweating has already been initiated). Furthermore, although the sweating response in the hairy regions is known to differ from that in hairless regions (palm and foot), where mental and emotional sweating occurs (Kuno, 1956;Ogawa, 1975;Sakakibara et al 1989), regional differences in the effect of the muscle metaboreflex on the thermoregulatory sweating response have not previously been studied. The purpose of this study was to examine whether the thermoregulatory sweating response can be modulated by the muscle metaboreflex and if so, whether there are any regional differences in the modulation of the response.…”

Intensity-dependent thermoregulatory responses at the onset of dynamic exercise in mildly heated humans

“…However, the initiation of dynamic exercise (7,19,31) and brief isometric exercise (3,17,28) under warm environmental conditions can increase the sweating rate (SR) without marked changes in the thermal factors. This indicates that sweating responses are due mainly to alterations in nonthermal factors that are associated with mental stress (23,36), central command (7,19,31,34,36), and stimulation of mechanosensitive (7,19,31) or metabosensitive (3,18,28) factors in exercising muscle. Also, it is suggested that the nonthermal sweating response during exercise is a feedforward mechanism of thermoregulation, because this response precedes changes in the thermal factors (31,36).…”