Sleep is Important
Your body temperature, blood pressure, breathing rate, and most other bodily functions slow down. Brain activity, however, never ceases. As a person sleeps, the brain organizes long-term memory, integrates new information, and repairs and renews tissue and nerve cells.
Sleep=Life. All mammals, birds and even some reptiles need sleep in order to stay alive. Sound dramatic? The fact is, going without sleep for more than 20 days leads to death.
There are two different types of sleep that your body cycles through each night:
- REM sleep (Rapid Eye Movement)
- Non-REM sleep
You alternate between these two stages of sleep about every 90-110 minutes throughout the night.
Approximately 75% of the sleep cycle is spent in non-REM sleep, which is the type of sleep that helps restore your body. This is the stage of sleep when you move from wakefulness to light dozing and finally to deep sleep. Brain activity slows, muscle activity is still functional, and breathing is low and steady.
REM sleep helps restore your mind. During REM sleep, brain activity is strong, and this is the stage of sleep when you dream. Eyelids flutter, breathing is irregular, and muscles remain immobile so you cannot act out your dreams.
You need both types of sleep to be healthy.
The sleep cycle is often compared to a roller coaster, because you go up and down from wakefulness to deep sleep throughout the night. A normal night’s sleep may include as many as five up-down cycles.