According to a medical theory one passes in sleep through many phases until one arrives at a state in which there is absolute rest and silence - it lasts only for ten minutes, the rest of the time is taken up by travelling to that and travelling back again to the waking state. I suppose the ten minutes sleep can be called susupti in the Brahman or Brahmaloka, the rest is svapna or passage through other worlds (planes or states of conscious existence). It is these ten minutes that restore the energies of the being, and without it the sleep is not refreshing.

According to the Mother's experience and knowledge one passes from waking through a succession of states of sleep consciousness which are in fact an entry and passage into so many worlds and arrives at a pure Sachchidananda state of complete rest, light and silence - afterwards one retraces one's way till one reaches the waking physical state. It is this Sachchidananda period that gives sleep all its restorative value. These two accounts, the scientific, and the occult-spiritual, are practically identical with each other. But the former is only a recent discovery of what the occult-spiritual knowledge knew long ago.