The body does not simply go to sleep it goes through phases and gets deeper and deeper over the course of the night until you wake up. During a normal night of sleep, a person will go through five phases of sleep. This means that as you sleep your body actually experiences different sensations during the five sleep phases.
Phases 0 is wakefulness. When we are experiencing wakefulness, our brains exhibit high brain waves, this is known as beta waves which allow us to consciously function during our waking hours.
Phase 1 sleep. During phase 1 sleep, our brain exhibits a combination of alpha and theta brain waves, this is our bodies begin to relax and prepare for sleep. This sleep phase is normally experienced while we are daydreaming, or feeling drowsy during the day
Phase 2 sleep. This phase is very interesting; it is where our brain exhibits sudden bursts of activity. Like the phase 1 sleep, people in the second sleep phase are still considered awake, this is also a transitional phase into actual sleep. During this phase the brain is attempting to ‘switch off’ in preparation for us to sleep. If someone is awoken during the second sleep phase, they often don’t remember having fallen ‘asleep’.
Phases 3 and 4 are considered ‘deep sleep’ – this is when you are actually asleep and if you are awoken, you will know you have been asleep. It is at this phase that the brain exhibits a combination of delta and theta brain waves. Our bodies physiologically adapt to the sleeping environment, we experience a drop in blood pressure, heart rate and respiration.
Phases 5 is termed REM sleep. REM is an acronym for Rapid Eye Movement, and very little is known by the scientific community about the purpose or activity that occurs during this sleep phase. Experiments conducted in the 1950s discovered that when people were in this phase of sleep, their eyes would move very rapidly, and if woken up during this phase of sleep, 95% of subjects reported that they have been dreaming. Thus, REM sleep is also known as dream sleep. The brain exhibits extraordinary high activity during this final sleep phase. The body generates chemicals that cause mussel paralysis; this is done to keep the body from acting out your dream. Night terrors are usually a result of lack of this mussel paralysis.
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