Why do we Sleep ? Mystery Explained !

If you are one of those who think that sleep is meant to give rest to our brain, then you must rethink as our brain works more while we sleep. This fact might make you think that sleep is meant to give rest to our muscles, but in that case sleep is not necessary as just lying down is sufficient to give rest to muscles. Our sleep is really a mysterious thing and scientists are still trying to find an exact answer to this mystery. If we look at animal kingdom then every animal sleeps and it makes them vulnerable to predators, but still we sleep. It suggests there there must be some serious benefits of sleep, that outweighs the danger that we face during sleep. Here betterhealthfacts.com will try to explain this mystery with latest facts available among the medical community.

Adenosine is a compound present in all human cells. During day time level of adenosine increases which makes is feel tired. During sleep our body breaks this compound and lowers its level and makes us feel fresh when we get awake. An interesting fact about Adenosine is that, when this compound is given as a drug then it has got the ability to stop our heart for 6 to 10 seconds temporarily by stopping the electrical activity in heart.  

Our body reacts to absence of light by increasing melatonin hormone which makes us feel drowsy and ready to sleep. During the early morning hours as sunlight increases our body releases cortisol hormone which increases energy level and alertness. These hormone cycles are directly affected by light and are part of circadian rhythm, our biological clock.

Do you know that blue light in your smartphone decreases melatonin level and don't let you feel enough sleepy, thus affecting your sleep cycle badly.

These hormonal changes trigger us to sleep and wake-up, but it does not explain why we sleep.

Why do we sleep ?

• Some researchers suggest that our brain glycogen level decreases during day. Night sleep gives our brain enough time to refuel the glycogen level.
• Some sleep scientists have found that our brain keeps working even during the sleep. Out of four stages of sleep, REM sleep is the time when we experience dreams, during which our brain waves are equivalent to an awake person. This fact mystifies the sleep even more, because if our brain remains that much awake then what is the usefulness of sleep. Some researchers have found that there is a mechanism of memory erasing that works during REM sleep. Basically this function works to erase the dreams that we are watching, but it also erases the useless temporary memories. It acts like a disc-cleanup of computers and provides some free neurons for further use. Read more about Why do we forget.
• Researchers have found that brain-cells of mice shrink during sleeping, which allows cerebrospinal fluid to flow easily. This fluid is present in the brain and spinal cord and sweeps away the waste material, which is then taken to lymph glands and flushed out of body. During sleeping time this extraction of waste is done efficiently, and all those toxins made during awake hours is cleared. Same process might be happening in human brain during sleeping hours, but it is hard to test.

Why do we sleep during night ?

We are evolved to sleep during night because nights have lower temperature. If we remain awake during night then our body needs to work harder to maintain the body temperature. 

However our brain keeps working during night, but most of those functions are for maintenance of our whole body including brain itself. Lack of sleep is a serious health issue which can cause a number of diseases, both physical and psychological. The main motive of sleep is much more than just resting of our muscles. We are evolved to sleep in night and accordingly developed our eyes.

We the humans have a safer a sound sleep compared to other animals. It might be one of the best reason to explain the better intellectual level among us. Our intelligence level gradually increased during past thousands of years as we started to live and sleep at safer places, where our sleep won't get disturbed by any predator.

Do you know that a sleep deprived person can have microsleeps. These microsleeps can last for just a few microseconds. Such microsleeps often remain unnoticed by the person. Apart from that sometimes only a part of brain sleeps, while the person remain completely awake. Such sleeps are hard to measure. Scientist often struggle to answer if sleep deprivation can kill ? The answer is not yet known. Our brain has got several features that we don't know about and our sleep is one of such mysteries.