Everybody sleeps. As a matter of fact almost every living thing sleeps. Many animals have adapted the amazing skill of shutting off parts of their brain to go to “sleep” and then shutting down the other half after a rest. Birds can do this in flight and fish can do this while swimming. Evolution has given these animals the skills they need to sleep, above anything else, but still be able to maintain movement long enough to stay alive. 

Even the apple

Your brain and body prioritize sleep over anything else once you really start to need it. Truck drivers fall asleep at the wheel every year from driving for days on no sleep and having their brain shut down on them.

But why? What is it about sleep that makes it so damn important? We learned a little bit about this in class that one hypothesis for sleep is the importance it has on our brains. We form new neurons and get rid of ones we don’t need. It releases stress and gets rid of chemicals in the brain that can damage cells as you stay awake. Is that it? Every single animal that exists had an ancestor that decided somewhere down the line the best way to solve those problems and do those things was to make yourself as vulnerable as possible to any threat you actively avoid during the day. In a world where everything wants to kill and eat you that doesn’t make a lot of sense evolutionarily. Sleep is so important to the human brain’s cleansing and healing process that it makes itself vulnerable just to get it done.

Sleep in neuroscience is defined as “a state that optimizes the consolidation of newly acquired information in memory.” It’s main purpose is to take the memories you kept from the day and decide what’s important about them, what to keep and what to get rid of. Of course it’s not just the new experiences of the day that become consolidated it’s the information you have deemed important over your recent past. When you’re constantly thinking about a movie you saw a week ago or the girl you met a few days ago that’s what is going to be running through your memory mills as you sleep. And your brain works very hard at night to do this. Without sleep you are unable to keep focused because sleep maintains all the information you’ve been dealing with in a time where the brain has no other obligations. As it’s awake it’s doing a million things just to keep you awake and alive, but at rest it can use that energy to clean the garbage out of its cells and deal with the massive influx of information.

One team of scientists compiled evidence on sleep and learning and concluded that each stage of sleep, slow wave sleep and REM sleep, holds a very important piece in memory formation. In sleep your brain establishes patterns of neurotransmitters and neurohormones to reactivate memories and create representations of them in your long-term memory. This process places them in two long-term memory categories, procedural and declarative. Procedural memory is your unconscious memory of skills and actions and relies below your own awareness. Declarative memory is the memory you can consciously recall at will. Almost all your ability to consolidate these forms of your long-term memory happen in sleep. If it was not for sleep your life wouldn’t be more than what happened to you in the last few days.