What happens during sleep?”Why do we sleep”? is a question for many people and has mystified scientists for thousands of years,Modern research has identified clues about what is the function of sleep and what happens to our body when we sleep.Many biological processes happen when we sleep:
- Our brain stores new information and get rid of toxic waste.
- Nerve cells in our body communicate each other and reorganize which supports healthy brain function.
- Sleeps affects almost every type of tissue and system in the body like brain,lungs,heart,metabolism,mood,disease resistance,immune function.
- Our body repairs cells,releases molecules likes harmones and proteins,restores energy.
These processes are very important for our body to function properly throughout the life.Infact,during sleep,our brain and body is remarkably active.
No doubt,we spend our one third of lives in sleeping. Our sleep timing is controlled by the circadian clock,sleep-wake homeostasis and in humans,within certain bounds,willed behavior.
Many experiments reveal that if we sleep for even eight hours saves even a minute amount of energy about 50kcal.Sleep is essential to maintain our cognitive skills such as speech,innovative and flexible thinking,memory.So sleep is a crucial part for brain development.A good amount of sleep during night helps a person to organize and archive his memories and get re-energized for the next day.
What happens during sleep: Case Study
Stages of Sleep
There are two types of sleep:
- REM(Rapid Eye Movement)
- non-REM(non-Rapid Eye Movement)
Each type of sleep is linked with specific waves and neuronal activity.We cycle through all the stages of REM and non-REM sleep several times during night with increasingly deeper,longer REM period occurring towards morning.
The changeover from wakefulness to sleep is non-REM sleep.During this short period,(lasting several minutes)of relatively light sleep,our heartbeat,eye movements,breathing get slow and muscles get relax with occasional twitches and your brain waves begin to slow from their wakefulness daytime patterns.
non-REM sleep is the period of light sleep before you enter into deeper sleep.So now your heartbeats and breathing slow and muscles relax even further.Your body temperature drops and eye Movements stop.Brain activity is also gets slow but is marked by bursts of electrical activity.This is the stage where you spend more of your repeated sleep cycles than other sleep stages.
non-REM sleep is the period of deep sleep that you need to feel refreshed in the morning.During first half of the night,it occurs in longer periods.Your breathing and heartbeats slow to their lowest level during this sleeping period.Yours muscles are more relaxed and it may be difficult to awaken you.Your brain waves even get slower.
Firstly it occurs about 90 mins after falling asleep.In this stage,your eye moves rapidly from side to side behind eyelids.Your breathing faster and irregular and your heart rate and blood pressure increases to near waking levels.Mixed frequency brain waves activity becomes closer to that seen in wakefulness.Most of your dreaming occurs in REM sleep and some can also occurs in non-REM sleep.During this time,your arms and legs becomes temporarily paralyzed which prevents you from acting out your dreams.As you age,you will be sleeping less in your REM sleep.Memory consolidation process requires both non-REM and REM sleep.(what happens during sleep)
There are two internal biological mechanisms-circadian rhythm and homeostasis,they both work together to regulate when you sleep and awake.
It direct a various functions from daily fluctuations in wakefulness to body temperature,metabolism and the release of harmones and proteins.They control your timing of sleep,cause you to feel sleepy and your tendency to wake up in the morning without an alarm.Your body’s biological clock which is based on 24-hour day,controls circadian rhythms.It synchronize with environmental cues like light,temperature about the actual time of day,but they continue even absence of cues.*what happens during sleep.
This mechanism keeps track of your need for sleep.The homeostatic sleep drive reminds the body to sleep after a certain time and regulates sleep intensity.This drive gets stronger every hour you are awake and causes you to sleep longer and deeply after a period of sleep deprivation.
There are various factors that influence your sleep-wake needs include medical conditions,stress,medications,sleep environment and what you eat and drink.However,The greatest influence experienced is the exposure to light.In the retina of our eyes,there is specialized cells which process light and tell the brain whether it’s a day or night and can advance or delay our sleep-wake cycle.Exposure to light can make you difficult to fall asleep and return to sleep when awakened.
Let’s take example of night shift workers,oftenly they have trouble falling asleep when they go to bed and they also have trouble staying awake at work because their circadian Rhythm and sleep-wake cycle is disrupted.So this is like creating a mismatch between their internal clock and the actual clock.