Most of us fail to get good nights sleep. As a result we run the risk of greatly increasing our susceptibility to disease and accidents. Getting a good night sleep is a minimum for a healthy life. For most people this amount needs to be around 6 to 8 hours each night.   Anything less than that and you are sleeping too little and anything more than that and you are probably sleeping too much.

What is it that sleep does for us? The best way to think of sleep is as the body’s form of “downtime”. Just like our computers need to go offline in order to be repaired so must our bodies. During this “downtime” the body actually rebuilds tissue, grows bone and muscle and strengthens the immune system. The truth is we really don’t know everything that does happen in sleep just yet. However, we know enough to realize that without it the body deteriorates along with the mind.

Each night we cycle through three stages of sleep including light sleep, deep sleep and Rapid Eye Movement Sleep (REM). Each of these stages are vital but the last stage is especially vital. Deprivation of this final stage of sleep can seriously decrease our health and productivity and make us increasingly prone to accidents and systematic disorders.

During deep sleep brain activity that controls emotions, decision-making processes and social interaction shuts down. Though these areas become inactive other areas of our brain that are usually dormant come to life. It is also at this stage that cell growth and cell repair takes place. There is in fact some truth to the phrase “beauty sleep”. Missing these vital areas of sleep deprives our body of the chance to revitalize our skin and organs.

Sleep is also integral in fighting off infection. As anybody who has been sick can attest the need for sleep increases when we are ill or bedridden. Part of the reason for this behavior is because our body is trying to shut down other aspects of our functioning in order to send much needed energy to our immune system and other parts of the body that help to fight off infection and sickness. This is a key step in the healing process. Depriving someone of sleep with a major illness can do serious damage to their long-term health.

The effects of sleep deprivation are many and varied. When we are deprived from sleep hallucinations and mood swings are usually the first effects we feel. There is also a general sense of irritability that pervades our waking mood when we are sleep deprived. Lack of sleep also affects our nervous system leaving us drowsy and unable to concentrate. Lack of sleep is also a frequent contributor to the causes of vehicular accidents and all other types of accidents, many of which are fatal.

To make sure you get the most of your sleep try to develop some ritual before going to bed. By creating a routine you condition your body to prepare itself for sleep. Avoid taking medicines since many of these prohibit the deepest levels of sleep, which are most necessary for our body. Also avoid excessive stimulation two hours before sleep. This can cause your body to be unable to fall reach the state of deep relaxation needed to fall to sleep.

When it comes to sleep, the longer you stay awake, the longer you sleep. The amount of sleep a person needs is determined by the Circadian system or the body’s internal clock. Reduction in blood pressure and heart rate are two processes that sleep induces.

The two basic distinctions that apply to sleep are NREM or non-rapid eye movement and REM or rapid eye movement. In the duration of one night they occur as a 90-minute cycle, repeating up to six times for the duration of the night in all four stages of NREM and REM. REM results from NREM.

Sleep Cycle

Four stages in a duration of almost 90-120 minutes makes one sleep cycle. Dreams are common to all stages with the most vivid and memorable in the last stage, the common term for which is REM sleep. The sleep cycle is repeated four to five times a night, sometimes going up to seven. This is the reason for many different dreams in one night. Usually the ones in the last stage prior to waking up are the ones recalled. Not being able to remember the others does not rule out their occurrence. Many are insistent about not dreaming when the truth is that they simply don’t remember doing so.

The Stages Of Sleep

On falling asleep, the transition sleep or stage 1 begins, progressing a few minutes later to stage 2 of baseline sleep. This is the stage leading to the other three and accounts for nearly 50-65% of sleep time. Another 15-20 minutes later, it reaches stage 3, followed by stage 4, referred to as delta sleep or slow wave sleep due to the very high voltage slow brain waves. Delta sleep has a lot in common to a coma, apart from being reversible. During the first four stages, a reduction takes place in respiration and heart rate with the body relatively immobile. After 30 minutes or so of slow wave sleep, there is a sudden lightening into stage 2, rapidly followed by a very active brain wave pattern called paradoxical or REM sleep. At the same time, respiration and heart rate accelerate with loss of postural and skeletal muscle control. Brain activation occurs simultaneously causing hallucinations and dreams.

NREM

In stages 1,2 and 3, it is NREM or non-rapid eye movement sleep, when dreams are not as vivid and eyes move. This inactive stage of sleep makes up 97% of sleep, with only 6% who awaken in NREM being able to recollect their dreams. NREM accounts for 78% of sleep.

REM

During REM or rapid eye movement, eyes move to and fro under closed eyelids. REM occurs in stage 4, for as long as one hour, repeating at 90 to 100 minute intervals, three or four times a night. REM increases brain temperature and makes breathing and heartbeat irregular. Blood flow is increased as well. Most awakening in REM recall dreams vividly due to the brain being very active.

REM sleep is considered important for memory and learning. The hypothesis for sleep in general and REM in particular, is of restorative nature. Loss of REM sleep causes irritability, anxiety and depression. Many lapse into REM rebound when REM sleep is insufficient. Therefore REM sleep periods are more frequent in occurrence with a longer than average duration.