Short review of human prolonged horizontal bed rest studies in Japan

As many as 700,000-1,000,000 Japanese are spending a substantial part of their life in bed not being able to resume standing position due to disease and/or accident. Our objectives were urgently derived from that fact. The research project group at Faculty of Medicine, University of Tokyo, in Japan have studied effects of prolonged horizontal bed rest on humans since 1990. Financial supports from the Japanese Ministry of Education (Grant-in aide for scientific research), National Aero Space Development Agency of Japan and Japan Federation for Health Sciences have enabled us to perform five prolonged bed rest experiments for 5 years from 1990 to 1994. Many scientists in Europe, America and Russia have already made a heap of studies on this subject since the latter half of 1940s (eg. 39). However, our studies mainly focused upon the effects of inactivity on human health to determine how to bring a human from inactivity back to an unrestricted active life. This short review is going to summarize our results obtained from 1990 to 1993.