Sri Aurobindo
Bases of Yoga
Bases of Yoga
It is not a right method to try to keep awake at night; the suppression of the needed sleep makes the body tāmasic and unfit for the necessary concentration during the waking hours. The right way is to transform the sleep and not suppress it, and especially to learn how to 
become more and more conscious in sleep itself. If that is done, sleep changes into an inner mode of consciousness in which the sadhana can continue as much as in the waking state, and at the same time one is able to enter into other planes of consciousness than the physical and command an immense range of informative and utilisable experience.