The saintly Rabbi, Chafetz Chaim, used to direct his yeshiva students to eat properly, get enough sleep, and take walks. Only if someone is healthy will he be able to study properly. Occasionally the Chafetz Chaim personally closed the lights in his yeshiva late at night to make sure the students got sufficient rest.
Love Yehuda
--
Visit my Blog: http://yehudalave.blogspot.com/