Sometimes, I keep myself up at night by thinking about the necessity of sleep. It's ironic, I know, but what does sleep actually do for us? Obviously it helps us recharge somehow, but most of us are unclear on how exactly that works, scientifically speaking. Even some of the leading experts on sleep psychology are unsure of the answer to the question "Why do we need sleep?" Although the true purpose of sleep is still relatively unknown, there are definitely some clear benefits to a good night's sleep.
From an evolutionary standpoint, psychologists and biologists think sleep might have been to protect early humans. By sleeping at night, they were inactive during a period in which they would have been very vulnerable. Many early nocturnal animals posed a great threat to the survival of early humans, so by getting away for the night, humans were protected from possibly running into any of these creatures. If this explanation of sleep seems out of date today, that's because it probably is. The evolutionary basis for sleep makes sense, but if we don't need sleep to serve this purpose any more, what other benefits could it have?
Another popular theory addresses the restoration of the body. During sleep, many biological processes occur, to include protein synthesis, tissue repair, release of hormones and other regulatory functions. In a series of recent studies, researchers found that many of these processes occur mostly, or even exclusively, during sleep. If you've taken intro bio already, you know how important these processes are for the natural growth and regulation of our bodies. If you've ever noticed that you're not on your "A-game" after an all-nighter, this is why. Protein synthesis in the hippocampus promotes memory and cognitive function, but this protein synthesis is severely impaired if you don't get enough sleep. Another recent study found that in rats, loss of memory and lapses in concentration could be linked significantly to the amount of sleep the rats got, and by tagging proteins, the researchers were able to track this phenomenon specifically. The regulation of biological processes seems like a pretty good reason to make sure you get a decent amount of sleep every night.
Another theory (which happens to be my personal favorite) is the idea that sleep actually changes the structure and function of the brain. It's called neuroplasticity, and although we still don't know much about it, scientists have noticed a clear correlation between sleep and brain development in young children. The brain develops rapidly during early stages of childhood, when children sleep the most. The implications of these studies are still unclear, but one thing isn't: sleep is important.
If you find yourself up late during the school year, take a minute to think about this. Are you going to gain more from staying up all night, trying to cram the material? Or are you going to get a solid six hours of sleep (even this isn't enough for our age demographic, according to most sources) and be well-rested and fully functional for that big assignment tomorrow? Personally, I'd take the sleep.