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).
The most vivid and realistic dreaming occurs in rapid eye movement (REM) sleep, which is concentrated more in the second half of the night. While some dream activity does occur during deep (or slow wave) sleep as well, it is much less formed and structured, and recall of the content of those dreams is much more limited. 2. In REM sleep, there is loss of almost all muscle tone, except for the diaphragm and eye muscles.