Hot Spring (Onsen) and Health

Abstract

　This paper describes the outline of balneology and the hot spring effect for the human body. Hot springs (onsen in Japanese) are defined by certain criteria for the ingredients and hot water temperature. The thermal effect, one of the physical effects of hot springs, expand blood vessels to improve blood flow and recover fatigue. In addition, the chemical effect as mineral content of hot springs enhances the thermal effect. Japan has 21 health promotion facilities using hot springs which are approved by the national government, and the cost of using these facilities is recognized as medical expenses under the Japanese tax system. The development of measuring instruments and epidemiological surveys at hot springs are necessary for the development of balneology.