An inactive state resembling deep sleep in which certain animals living in cold climates pass the winter. In hibernation, the body temperature is lowered and breathing and heart rates slow down. Hibernation protects the animal from cold and reduces the need for food during the season when food is scarce. Compare estivation.
Does Dreaming Indicate a Good Nightâs Sleep? Dreams are typically indicative of a good nightâs sleep, demonstrating that you have passed through the light sleeping phase (NREM) and entered into a deep sleep (REM).
This is called a lucid dream. Research has shown that lucid dreaming is accompanied by an increased activation of parts of the brain that are normally suppressed during sleep. Lucid dreaming represents a brain state between REM sleep and being awake.