3/31: How little we know about sleeping

Everyone does it, for 7–8 hours every day we disconnect ourselves from the real world to enter to an unknown land called dreaming, where anything can happen. But we are not still sure why.

Sleeping is an important part of our lives

The truth is science still doesn’t know why we need to sleep. There are some theories that can explain in a sort of logic way why we do it, but the lack of experimenting in this area haven’t helped to find an explanation of this natural phenomena.

If we trace sleep through the evolutionary tree we would find that practically every animal needs to sleep. While certain animals do it a little bit different, like Sharks and Dolphins which usually rest one half of the brain at the time. But the necessity of sleeping is always present.

From a survival point of view, staying still for a long period of time doesn’t seem to be the best thing for an animal, but still all animals do it. The average time of sleeping varies a lot from species, so there isn’t a thumb rule for this. But still, all the processes that are made while sleeping are more important than staying awake 24 hours.

The benefits of sleep are well known. It helps to keep us alert the rest of the day, a lot of the reconstruction process of bruises and injuries are performed in this stage, before reaching the growing period animals grow while they are sleeping, almost all the physiological process are activated while sleeping, that’s why we know it’s a crucial part of survival for animals. But still the origin can’t be explained, and we don’t really know why we dream.

But which are the theories that we have now about sleeping? Why sleeping is so important for humans? Well, all of these theories are usually related to the brain and its own regeneration cycles that are needed to keep a good health, both mental and physical.

Flush theory. Some specialists think that the brain needs to sleep in order to get rid of all the chemicals produced by the day activities. At the end of the day, the brain is an organ that works with chemical reactions and at some point it needs to get rid of all the waste that was produced during the day. Sleeping could be a solution to flush everything without taking care of the processes that are needed when the body is awake.

Memory processing. This is one of the most popular theories, because it’s the most logic one. The brain works like a big library that receives data that needs to be stored, but not all the data we receive should be passed from the short term memory to the long term one, so while sleeping the brain does this curation process where it decides what should be kept and what not. This one also explains in certain way why our dreams are usually influenced by our recent experiences.

Restart theory. This one is easier to explain in our current time, it may be possible that the brain needs to restart itself like a computer. All the synaptic connections that were made in the day and were kept like this need to be restarted at some point. It could be possible that the brain goes to sleep in order to restart these connections, that’s why our dreams include experiences, ideas or feelings that were part of our day.

Preservation. This theory supports the idea that sleeping is a way to keep the body of risking itself for that period of time. An animal doesn’t need to be awake 24 hours to perform all the daily processes, also the brain is one of the organs that consume the most resources in the body, so sleeping is a way of reducing the consumption levels of the brain, while keeping the animal safe from the external environment, because all the animals look for a secure place to sleep. This theory tries to explain why sleeping exists, it’s possible that after sleeping became a part of ancient animals lives then other metabolic processes took advantage of the sleeping period.

These are only some of the theories that you can find about sleeping, of course there are more of them, because the less we know about something the more theories you will find about that certain topic.

A lot of research is made by different psychology schools in order to find a possible explanation about the sleeping cycle.

And this are the theories that try to explain why we sleep, psychologists wonder also about dreaming and why it’s a crucial part of sleep. Do other animals dream? Why does the brain need to have dreams? Are they connected?

Dreaming has been proved in other animals like mice, cats, dogs, and all mammals. It’s also present in a big number of birds and reptiles. So it’s not hard to understand that dreaming and sleeping are directly related.

Experiences reaffirmation. Some scientists believe that we dream in order to reprocess some of our new acquired experiences. It’s a way the brain can practice again what it learnt the previous day. It may be possible that primitive animals evolved dreams as a way to train, in a sort of sandbox world, what they just learnt. Dreaming would be a way to assure the right brain connections were made to perform them in the real world.

Long term memory. Other scientists believe that dreaming is just a consequence of the memory management process. While the brain is choosing between which memories are kept in long term and which ones need to be flushed away, it might be possible that the brain needs to reproduce them. This theory then takes two different paths, one of the branches believe that our dreams are a way to reprocess the memories that would become part of the long term memory in order to store them as they should; the other branch believes that the memories that are not going to be kept are the ones that are part of our dreams as a way to trash them, so the brain needs to reproduce the memory while it’s getting rid of it.

Random evolution theory. This theory says that dreaming could be just a random process that evolved from sleeping but it has not a real purpose. It believes that at the beginning the small brains of early animals weren’t as complex as they are today, so they weren’t able to dream because the sleeping process was simpler. With the evolution of more complex brains dreaming became a part of sleeping without any reason, just as a result of the increasing complexity of the brain structure.

There are even more theories about why we dream, because it’s harder to prove in a lab the benefits of dreaming, so what we really know about this topic is even less than what we know about sleeping.

If you are interested in knowing a little bit more about this I recommend you Dreamland: Adventures in the Strange Science of Sleep by David K. Randall. Which is a great recompilation and explanation of all the different theories and experiments performed trying to solve the mystery of sleeping and dreaming.


This story is part of my 31/31 challenge. Following a friend’s idea I will publish at least one story every day for the next month.

If you see any error please let me know, the idea is to stop over-reviewing my stories before publishing them.

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