The technical report is intended to support efforts by the prefectural government of Hyogo (Japan) towards a comprehensive system for public health prevention of heat disorders. It is the result of an evidence-building process involving relevant stakeholders at the local and national level in Japan. The state of the science regarding public health action on heat waves is reflected only as required by practical purposes, and is based on published scientific literature, as well as the gathering of critical inputs from experts within and outside the World Health Organization (WHO).