When we sleep, our brain undergoes 5 different sleep stages. Each sleep stage shows a different activity of brain wave and serves a particular purpose. When we are awake, our brain is active at its highest levels. These brain waves are known as beta. Beta waves are related to conscious active thinking. This is the stage where a majority of sufferers of insomnia are found as they remain awake all night long. Before the human body can slow down all its processes and rest at night, the brain has to undergo a sequence of slowing down and then sleeping.
The first of the sleep stages is known by many names like trancing, zoning out, day dreaming and so on. It is associated with self hypnosis or hypnosis. It is the stage where we fall asleep and our brain enters the pattern of alpha waves. A person is somewhat aware in the first stage. Sounds could be enhanced. Awareness is shifting inwards. If a person looks like he is falling asleep and you ask him if he is sleeping, he will give a negative answer. This is because anyone can easily come out of the first stage of sleep. This stage is also the most effective when catching 40 winks as the brain gets to rest as well as replenish but the body does not have to shut down. The first stage could be 10 to 15 minutes long and will be different for everyone. The second of the sleep stages involves sudden bursts of activity in the brain. The body starts shutting down at this stage. Random leg and arm movements might be seen here. This is the reason why we are startled into waking up when we fall asleep in public. The on off switch into deep sleep sees to it that the position of the body is secure and safe before it is shut down completely. At this stage, patterns of brain waves are called K-complexes or sleep spindles due to the peaks and valleys that are formed on graphs. The third and fourth sleep stages involve deep sleep that is very difficult to wake from. It leads to grogginess. The brain reaches its lowest frequency known as delta waves. The body shuts down completely here and is rejuvenating. When we are in deep sleep, our heart rate, breathing and blood pressure is at the lowest. There is a complete dilation of blood vessels. Blood flows to those parts that are usually turned off. Muscles get repaired and nourished. In the course of a regular night, the 4th stage is reached only in the initial few sleep cycles. It might not even be reached if body remains inactive. Hence, activity is very important.
The last of the sleep stages is REM sleep, Random or Rapid Eye Movement. It is most fascinating as this is when we dream. Scientists have not been able to find its true purpose. There is a lot of debate on this. It is assumed that this stage allows brain to recollect the experiences of the day and process all that was learned.
