How Do We Sleep?

How Do We Sleep?

During the sleep cycle, the human body undergoes anabolism, which means that it uses energy to produce or repair tissues such as bones, spinal cord, brain, and muscles etc. Hormones also play a role in inducing our bodies to sleep by responding to signs within the body and also to external stimuli.

Though a person might appear to be inactive during sleep, the body is actually carrying out important functions. These functions are actually more critical during sleep than during consciousness. For instance, our respiratory system undergoes change during the sleep cycle. Our breathing patterns are much more regular and controlled during sleep. On the other hand, when we are awake, our breathing is affected by many factors such as movement, posture, weather, emotions, exercise, and speech etc. Other functions include changes in cardiovascular activity, thermoregulation or body temperature, brain activity, and miscellaneous physiological activity.

There are mainly 4 different stages of sleep that the human body experiences. These stages include NREM Stage 1, NREM Stage 2, NREM Stage 3, and REM. NREM here stands for Non-Rapid Eye Movement and REM stands for Rapid Eye Movement.

The NREM Stage 1 is the initial stage of sleep. It usually occurs between being awake and deep sleep. It is characterized by active muscles and eyes that roll slowly while showing moderate movement.

In the NREM Stage 2, the body enters a phase of light sleep right before going into deep sleep. This stage is characterized by a drop in body temperature and a decreased heart rate.

In the NREM Stage 3, the body enters into deep sleep and enters a phase of inactivity. It is generally hard to arouse from this state and if aroused, can result in temporary disorientation.

The REM or Rapid Eye Movement stage is the final stage of sleep and occurs after 90 minutes after the body goes into deep sleep. In this stage, the brain becomes active which leads to dreaming. Each REM cycle gets longer as you sleep. The first REM cycle lasts 10 minutes while the final one can last up to 60 minutes. There is an increase in heart rate as well as respiration during the REM stage. Adults spend about 20% of their sleep time in the REM stage while infants and young children have been observed to spend 50% of their sleep time.

Sleep is something that is shared between all organisms on earth. It is a function that all living creatures have exhibited since the beginning of their existence. Sleep has been a subject of study for several years and continues to arouse the curiosity of experts everywhere. Though our perception of sleep might have changed over a period of time, our requirement for it has not.