Keiichi Yoshida

Thermal reaction and manual performance during cold exposure while wearing cold-protective clothing

Abstract Subjects were exposed in a climatic chamber for 60min to air temperature at — 5, —15 and — 20°C wearing cold-protective clothing with cotton working gloves. Subjects were asked to perform a 15 s counting task using a manual counter as fast as possible with the right hand, at approximately 15-min intervals during cold exposure. Skin and rectal temperatures were measured. On cold exposure, skin temperatures and body temperatures dropped gradually; after 1 hour most sites were colder, especially hand and finger temperatures. Finger temperatures decreased gradually with time, and steeply at the lower air temperatures, being temporarily raised by the counting task performed and possibly by cold-induced vasodilatation. By contrast, the gradual decline in hand temperatures showed no such transient changes. The decline in task performance with time was greater the lower the air temperature. The performance at -20°C decreased significantly with each further 15min exposure in comparison with the values bef...

Physiological reactions to different vertical (head-foot) air temperature differences

Six healthy male subjects were exposed to different vertical air temperature differences between the upper and lower parts of the body for 90 min, wearing light clothing. The lower part of the body was exposed to an air temperature of 25°C and the upper part of the body to air temperatures of 15, 20, 25, 30 or 35°C. The preferred air temperature was different from those for uniform experimental conditions found by other investigators. The thermal sensations on the upper part of the body and the whole body were similar, and those on the lower part of the body were almost constant under each condition. From the relationship between thermal sensation and mean skin temperature, subjects may feel thermal neutrality at a slightly lower mean skin temperature, when the lower part of the body is at a comfortable temperature, than when both upper and lower parts of the body are exposed to the same temperature. The lower part of the body was exposed to thermally neutral condition and the skin temperatures of the low...

RHYTHMIC CIRCULATORY CHANGES IN THE PERIPHERAL VASCULATURE

In 1946, the term, “vasomotion,” was applied to spontaneous rhythmic contractility in the peripheral vasculature when it occurred a t slow rates in the arterioles of the mesoappendix of the rat.l Since 1954, the term, “microcirculation,” has been used to describe the flow of blood through the peripheral vasculature at the level of capillarie~.~J Investigators in this field have used various species and different techniques and have postulated some principles of microcirculation. In an attempt, first, to focus on a particular aspect of the circulatory rhythm, we shall refer to our results obtained on the microcirculation by way of the rabbit ear chamber t e ~ h n i q u e ~ ~ and then extend references to related studies, especially to those done in human beings by Takagi and Nagasaka.?