Rascher was also tasked with discovering how long German airmen would be able to survive if shot down above freezing water. His victims were forced to remain out of doors naked in freezing weather for up to 14 hours, or kept in a tank of icewater for 3 hours, their pulse and internal temperature measured through a series of electrodes. Warming of the victim was then attempted by different methods, most usually and successfully by immersion in very hot water, and also less conventional methods such as placing the subject in bed with women who would try to sexually stimulate him, a method suggested by Himmler.