The Different Stages of Sleep
You may think that once you drop off then you sleep soundly until you wake up. However that isn't the case. In fact, there are several different stages to your sleep every night.
Usually when you go to sleep, there are different stages that you go through from the time you sleep until the time you wake up. When you have a sound sleep, you will wake up with a felling of refreshment. This is because how we sleep has an effect on how we will behave, feel, look and the overall quality of life.
While we are asleep, there are other parts of the body that remain alert. The brain specifically has a lot going through it during the sleep. Such activities in the brain are what define the stages of sleep that a human being goes through.
By definition, sleep is a state of mind that occurs naturally, characterized by the altered consciousness of the mind, the sensory activity and the voluntary muscles. While sleeping, most of the systems are in an anabolic state. The sleep appears in periods that recur and makes the body alternate between the Rapid Eye Movement (REM) and the non-REM. Generally the human being goes through four stages of sleep.
The stages starting from stage 1 to 4 go back and forth throughout the whole sleep time. One complete cycle of the sleep will take between 90 minutes to 110 minutes. When you go to sleep, the first sleep cycle will have short REM sleeps registered with long deep sleeps, but the condition tend to change as the night progresses, with the REM increasing and the deep sleep reducing.
This is the first phase of the sleep cycle. It is the transitional stage between being awake and sleeping. The brain produces high amplitude waves known as theta waves, which are the slow brain waves.
The stage lasts for a short time, between 10 to 15 minutes and one can easily return to be awake. The stage really takes place after one has decided to sleep by closing eyes.
When someone is awakened up at this time, they will decline to have slept. The body muscles are not usually inhibited. The heartbeat which might be fast will become regular and the breathing will slow down at this stage.
The body temperature as well as the blood pressure will also decrease, and it is at this point that people sometimes experience movement and jerking motions. The person will be aware of the sounds around them but will be unwilling to respond to them.
This is the onset of the sleep, and it usually takes not more than 20 minutes. Here the brain will produce rapid and rhythmic waves referred to as sleep spindles which are larger waves.
The stage is characterized by the body temperatures decreasing and therefore requiring one to sleep in a cool room. The rate of the heartbeat also slows down.
The person will become disengaged from the surrounding activities. The body usually reduces its activities so as to allow you to enter into the deep sleep state.
It will be very difficult to wake up the person from this stage. It is at this stage that people spend most time during the entire sleep; about 45 percent of the sleep is in stage 2.
This stage is referred to as the delta stage sleep, because the brain produces a certain type of waves referred to as delta waves, which are the slow brain waves. It occurs between 35 and 40 minutes after a person has fallen asleep.
The person will less be responsive to the noise and the activity around his surroundings. This is the transition point between the light sleep and the deep sleep, within a short period of time the person will be in deep sleep.
The muscles are usually relaxed and therefore give way for tissue repair and growth. The blood supply to the muscles is also restored at this stage, paving way for energy restoration.
It is also referred to as the REM sleep. It is the final sleep of the sleep cycle. This happens after you have been asleep for about 90 minutes. The Rapid Eye Movement indicates that the eye moves rapidly in all directions.
This is where there is deep sleep, and powerful dreams happen here. Some of the characteristics include sleepwalking and wet dreaming.
The person also registers an increase in the respiration rates as well as the heart beats. This stage gets longer as the night progresses, with the last stage lasting about 60 minutes.
Usually, sleep does not progress from the first stage to the fourth one in sequence. The second stage is repeated after the third stage before entering in the REM stage.
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