Regional relationship of water vapor pressure of human body surface

¹ Department of Physiology 2nd Division, Nagoya City University Medical School, and Department of Dermatology, Nagoya University Medical School, Nagoya, Japan

A new simple method for measurement of water discharge from the skin, as well as for estimation of absolute and relative humidity of the skin surface, was reported. The accuracy of the method was high with errors in the order of 2.5%. Estimations were made, using this method, at 108 points over the body of a young healthy nude male subject under neutral thermal conditions. Regional relationship of the rate of insensible perspiration, as well as the absolute and relative humidity of the skin surface, were obtained from the experiments. There was no difference between the regional relationship of the insensible perspiration and that of the absolute humidity. In the regions where perspiration rate is high, the water vapor pressure of the skin surface is also high. Sole, face, palm, and neck are the highest regions. Back of hands and gluteal region are the second highest zone. In distal parts of extremities, there exists an increasing gradient toward the palm or the sole. In the median region of the chest and epigastrium the values are somewhat higher though the chest and abdomen as a whole belong to the lowest regions. Distribution of the relative humidity showed no great difference in general from that of the perspiration rate or absolute humidity. It was found that the regional relationship is not perfectly symmetrical in both sides of the body.