The unconscious is based on all we were conscious of before this moment, so that the dreaming mind is part of the unconscious of our waking mind, forming our intuition, and the waking mind is part of the unconscious of our dreaming mind, forming our reason. The two are combined into lucidity in dreams or into hypnosis in waking. To combine the two, we must remain at the point between waking up and falling asleep, and the easiest way to do so is to go back to sleep after waking up for 1 hour before the last sleep cycle (1,5 hours), during which we dream the most. After 6 hours of sleep it’s hard to fall asleep again, but as we only need 6 hours of sleep, 1 2 we could instead have our last sleep cycle after waking up from 4,5 hours of sleep.
1 NYTimes: Study Ties 6-7 Hours of Sleep to Longer Life
2 Telegraph: Five hours' sleep is enough, study finds