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:
“Man has lost the basic skill of the ape, the ability to scratch its back. Which gave it extraordinary independence, and the liberty to associate for reasons other than the need for mutual back-scratching.”
—Jean Baudrillard (b. 1929)
“May they rest in peace.
[Requiescant in pace.]”
—Missal, The. Order of Mass for the Dead.
The Missal is book of prayers and rites used to celebrate the Roman Catholic mass during the year.
“The superstition respecting power and office is going to the ground. The stream of human affairs flows its own way, and is very little affected by the activity of legislators. What great masses of men wish done, will be done; and they do not wish it for a freak, but because it is their state and natural end.”
—Ralph Waldo Emerson (1803–1882)
“The cycle of the machine is now coming to an end. Man has learned much in the hard discipline and the shrewd, unflinching grasp of practical possibilities that the machine has provided in the last three centuries: but we can no more continue to live in the world of the machine than we could live successfully on the barren surface of the moon.”
—Lewis Mumford (1895–1990)