The Different Stages of Sleep

In recent years, more information about what our brains do during sleep has emerged.  Below is a summary of these findings and the benefits of sleep.

Stage1:  Light Sleep.   When a person begins to sleep, their muscles relax.  Because the body is less physically active, the temperature lowers slightly.  The brain wave activity is still highly active.

Stage2: Transition.  The breathing and heart rate slow.  The brain waves start to slow down.

Stage 3:  Deep sleep.   The electrical brain waves are now at their slowest.  The brain is in a state where it is least receptive to external stimuli.

Stage 4:  Rapid Eye Movement (REM).  During this stage, it is believed that the brain relives the day's memories.  It is during this stage that dreams take place.  The eyes move rapidly.  The heart rate and blood pressure increase.  The body is in a state of paralysis.

At the beginning of the night, the lack of light is monitored by the eyes, which then relay this information to the brain.  A specialised part of the brain interprets this information and then controls how sleepy or awake you feel.  It does this by telling the pineal gland (located at the base of the brain) to release a sleep-inducing hormone, called melatonin.  Another gland called the pituitary gland releases growth hormone.  This helps to repair damaged body tissue during the night. 

A person goes through the sleep stages several times during one night.  By the early morning, the sleeper spends most time in the REM stage.  This is why it is possible to remember dreams straight after waking up.  By morning the brain will have helped to process the previous days memories, and to have repaired damaged tissue.

Why do we dream?

In the early 20th Century, Freud suggested that dreams were the brains way of dealing with memories and thoughts, buried in the subconscious.  Today the theory has become more detailed.  Using specialist imaging equipment, scientists now suggest that dreams are the minds way of dealing with the emotional aspects of memories and thought.

During REM sleep, the 'emotional brain' (the limbic system) is highly active whilst the rational brain (prefrontal cortex) is off-line.  Therefore, it is the limbic system where the emotional content is contained.  Through dreams, the limbic system brings these emotions and moods to the attention of the brain to deal with.  The same can be said for nightmares.  A person may have nightmares after experiencing a traumatic event.  The extreme of this is called night terror, were the person may actually wake up sweating and screaming from the experience.

It has been found, that people tend to have bad dreams at the start of sleep and progress through the night, with better dreams being experienced by the morning.  This process is thought to be the way in which the brain works through the negative emotions, in order to wipe the board clean, ready for a new day.

Some Tips for a good nights sleep

1) A glass of milk (preferably warm) before bedtime can help to induce sleep.

2) Trying Progressive Muscular Relaxation (PMR).  Gradually tensing and relaxing body muscles.  Starting from the feet and working up to the face.  With deep breaths throughout.  This often takes some practice.

3) Counting from 100 to 1!  This may sound like too much work, but it can be done.  Especially when you are experiencing constant thoughts.

4) Lavender scented container next to the pillow.  For some the scent can induce relaxation, which in turn aids sleep.

5) One of the main reasons for lack of sleep, is sleeping on a curved mattress.  Position extra mattress layers to support your lower back.  This is very good for when you sleep on your side.

Latest Research

* Having a 'power nap' in the afternoon (10 to 20 minutes) can boost concentration for the rest of the day.

* The brain has its own 'sleep switch'  (a clump of cells called the suprachiasmatic nucleus), which turns the brain on in the morning and off before sleep.  That's provided your 24-hour biological clock is in sync, and you're not worrying about work, bills, mortgage etc!

* Further evidence is supporting the idea that during sleep, the brain files away information that has accumulated during the day, into the long-term memory storage.  This frees up space in the short-term memory storage, which can then be used for the following day.