What is sleep? If we go by the scientific definition, it can be defined as the natural and periodic state of rest during which consciousness is suspended. It is the time when our body and mind relax and get ready for next day’s work. Scientists have since long tried to decipher the mysteries behind this natural process. What happens after we fall asleep? Do we see dreams all the while? Different theories have come up in response to these questions.
Sleep can be categorised into different categories- deep slumber, light sleep, falling asleep immediately etc.Â Falling asleep constitutes the stage one of falling asleep. The mind starts to relax and a person starts drifting away into the mysterious world of sleep. The breathing becomes slow, heart beat becomes more regular and blood pressure decreases. It is easier to wake up a person during this stage and the person would not feel if he actually fell asleep.
After 15 to 20 minutes of falling asleep, we descend into the stage two of sleep. During this point of time, the brain does not show any change in the brain wave pattern. It is slightly difficult to wake up a person from this stage of sleep. A sound in the close vicinity may wake up a person.
After 30 to 45 minutes of falling asleep, the brain wave pattern changes. At this stage we move into the stage 4 of deep sleep. At this time, it will take a lot of efforts to wake up a person. Only a very loud noise may wake up a person. If woken up from this stage of sleep, a person feels groggy. The metabolic activity of brain decreases during deep sleep.
During the deep sleep our body and mind replenish and rejuvenate. Hypothalamus signals the pituitary gland to increase the secretion of human growth hormone(HGH). HGH is also referred to as ‘fountain of youth’ as it enables to restore the youthful state. It promotes tissue building and growth in children.
During the Rapid Eye Movement(REM) the brain waves shift again and eyes flutter back and forth under closed eyelids. It is during the REM that we dream.
For a healthy body and mind, it is essential to take 6 to 8 hours of sleep everyday. Sleep disorders are caused by the lack of proper sleep. It can be avoided by maintaining a proper sleep cycle.