The existence of a Basic Rest - Activity Cycle, or BRAC, during both sleep and wakefulness was proposed by Nathaniel Kleitman.
It is a human biological cycle of approximately 90 minutes (80–120 minutes) that is characterized by different level of excitement and rest. The cycle is controlled by the human biological clock. It is best observed in stages of sleep, for example, REM and the delta activity cycle.
Famous quotes containing the words basic, rest, activity and/or cycle:
“I fly in dreams, I know it is my privilege, I do not recall a single situation in dreams when I was unable to fly. To execute every sort of curve and angle with a light impulse, a flying mathematics—that is so distinct a happiness that it has permanently suffused my basic sense of happiness.”
—Friedrich Nietzsche (1844–1900)
“The rest I keep silent; a great ox stands on my tongue.”
—Aeschylus (525–456 B.C.)
“Criticism is infested with the cant of materialism, which assumes that manual skill and activity is the first merit of all men, and disparages such as say and do not, overlooking the fact, that some men, namely, poets, are natural sayers, sent into the world to the end of expression, and confounds them with those whose province is action, but who quit to imitate the sayers.”
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“Oh, life is a glorious cycle of song,
A medley of extemporanea;
And love is a thing that can never go wrong;
And I am Marie of Roumania.”
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