Why do people need to sleep?

There is nothing better than a good night's sleep. But have you ever wondered why this is true?
It's hard to understand how important sleep is to stay healthy and feel good until you do not sleep enough. But if you add up the number of hours you spend sleeping, that equates to about a third of your life – so this must be used for something.

No animal, including humans, can survive without sleep. As early as 1894, Marie de Manacéine, a Russian doctor and scientist, discovered that when he kept the puppies in constant activity without sleep, they died after a few days. As for us humans, scientists and scientific citizens, we have deprived their sleep or sleep researchers of their sleep for extended periods and have all noted similar effects: distorted sense of time and immense fatigue.

The most notable is the case of Randy Gardner. Still alive, Gardner is the world record holder for the longest time that a man has willingly deprived himself of sleep. In 1965, at the age of 16, Gardner remained awake for 11 days and 24 minutes. At the end of the stunt, his speech was blurred, his thinking was fragmented and he was not able to do a simple math longer than a few minutes.

Since then, some scientists have deprived volunteer participants of several hours of sleep for several days. They then tested the effectiveness of their noggins by submitting various cognitive tests. They found that participants suffered less each hour of lost sleep and better if they had a complete night of rest.

Many scientists have wondered why sleep gives our brain such momentum. After all, it would be ideal if we did not need to sleep at all: closing the eyes makes animals vulnerable to predators. They think that sleep is important for two main reasons: it helps us repair and restore our organ systems, including our muscles, our immune system and various other hormones. And this plays a crucial role in memory, helping us retain what we have learned at work or at school for later use.

Scientists have found that sleeping well seems to help our immune system function better. As our body is resting, the immune cells known as T-cells spend this time running around our bodies. Other immune cells also work better with more sleep. Researchers have been studying how our body responds to vaccines, drugs targeting the immune system, after a night of rest and no night's sleep. They found that sleeping well at night after a vaccine creates a stronger immune response to the virus that a vaccine is supposed to attack.

Other scientists have also examined the impact of sleep on learning and memory. Every day, at work or at school, we learn new things. But the ability to remember and use this information later seems to rest on sleep. In one study, the researchers gave the same information to two groups of teenagers and told them they would be tested. One group learned this information at 9 am and took the test 12 hours later at 9 pm that same night. The other group learned this information at 9 pm, rested a full night and passed the test at 9 am the next morning. Even with no extra study time, students who slept in-between did 20% better on tests measuring their knowledge of the subject.

There is still a lot we do not know about the potential benefits of sleep, but one thing is certain: we can not survive without it. And the closer we get to the amount of optimal sleep (eight hours for adults and more for kids and teens), the better we could be.