Q. If one does comply with a mitzva by just sitting in a shul or beis medrash, if one gets tired during learning and needs to stop, should he better remain in the beis medrash (rather than start walking around, talking a walk, etc.)? Should one stay and comply with this mitzvah when he puts his head down, etc. on a shtender, or falls asleep on a chair?
A. Shulchan Aruch (O.H. 151: 2-3) permits sleeping in a beis hameresh and in need even in a shul, Mishna Berura (ibid. 16) quoting R’A Eiger debates the permissiveness, but concludes that for a Talmid Chacham who constantly learns there, even a night sleep is acceptable.
Kinyan Torah (4: 15) quoting Divrei Chaim mentions that there is added leniency in Chassidik shuls that were established with specific tolerant conditions and therefore referred to as a “shtivel” or a room.
However, Horav Shlomo Miller’s Shlit’a opinion is that it is better, for the kavod and honor of the beis hamedresh to exit to another room and sleep there even temporarily, when possible.
Walking around the place may also be disturbing to others learning.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a