Sleep
Sleep is a naturally recurring state characterized by reduced or absent consciousness, relatively suspended sensory activity, and inactivity of nearly all voluntary muscles. It is distinguished from quiet wakefulness by a decreased ability to react to stimuli, and is more easily reversible than being in hibernation or a coma. Sleep is a heightened anabolic state, accentuating the growth and rejuvenation of the immune, nervous, skeletal and muscular systems. It is observed in all mammals, all birds, and many reptiles, amphibians, and fish.
Read more about Sleep.
Famous quotes containing the word sleep:
“A solitary traveller can sleep from state to state, from day to night, from day to day, in the long womb of its controlled interior. It is the cradle that never stops rocking after the lullaby is over. It is the biggest sleeping tablet in the world, and no one need ever swallow the pill, for it swallows them.”
—Lisa St. Aubin de Terán (b. 1953)
“Only when one cannot sleep does one know how long the night is.”
—Chinese proverb.
“My one and noble heart has witnesses
In all love’s countries, that will watch awake;
And when blind sleep falls on the spying senses,
The heart is sensual, though five eyes break.”
—Dylan Thomas (1914–1953)