Like eating, sleep must be kept to a minimum: only as much as is needed for regaining the strength to carry on a life of Torah and mitzvoth. As well as the effort to supervise sleep, Haredim aim to keep it as short as possible, be that by getting up at dawn or sometimes even in the middle of the night, and through exercises in waking up quickly.
In Haredi folklore stories are told of rabbis who can make do with a cup of tea and two biscuits a day, and one hour’s sleep a night. Torah students boast about and compete over sleepless nights devoted to studying Gemara. In addition there is the weekly “guard”: Thursday’s studies carry on all through the night until sunrise the following day.
When Haredim experience tiredness, they feel that they are spoiling themselves and being tested by bodily temptations.
They react aggressively to napping during study, and laud a legendary rabbi who never “dozed off” in the Bet Midrash. A yeshiva education includes various techniques for overcoming fatigue. An ascetic cult has developed, which includes self-torture aimed at preserving attentiveness, despite long hours of study. Throwing a glass of cold water over one’s head does not cause a stir among onlookers.
In small study houses in Haredi neighborhoods I saw persistent students who, when their eyelids began to droop in the early hours of the morning, would pound their fists or head on the table to the point of acute pain so as to prevent dropping off. It is told of a certain rabbi that at times like that he would stamp on his own toes until he drew blood.
Taken from “Denial Does Not Make The Haredi Body Go Away Ethnography of a Disappearing (?) Jewish Phenomenon”, By Prof. Gideon Aran.