At Semester’s Start, Don’t Dismiss the Importance of Sleep

Joshua Kogan, Columnist

I decided to try something new during my last semester at Oberlin, and write a column for our lovely local paper, The Oberlin Review. I majored in Biology, so I will try to write about topics of interest to biologists that are also relevant to Oberlin students. For my first article, I’d like to talk about sleep, something that no student here can seem to get enough of. Between classes, clubs, ExCos and Splitchers, who can find the time? And when you think about it, what is the deal with sleep anyway? Why do humans, and for that matter all animals, need to go unconscious for a third of our lives to survive? This adaptation doesn’t seem like something that would help our early ancestors survive against the forces of nature.

The short answer to these questions is … we don’t really know. But scientists have begun to shed some light on how sleep works and why it exists. Hopefully after reading this article, you will start to pay more attention to your sleep schedule and figure out what works and what doesn’t.

Lately, it’s come to my attention that it’s really important for me to get the right amount of sleep. Too little sleep, and I feel tired the whole day, with that special type of headache that only a good night’s sleep can cure. Surprisingly, when I oversleep, I feel worse, my thoughts are cloudy and it’s hard to concentrate or feel motivated. This wasn’t always true. I remember struggling freshman year to make it to Stevie brunch before it closed at 2 p.m. I must have been sleeping for 10 to 12 hours. Scientists and non-scientists alike have known for years that children and teenagers need more sleep than adults, but why is this the case?

When we sleep, we go through what are called sleep cycles, intervals of about 90 minutes that consist of both non-rapid eye movement and rapid eye movement phases. An average person will go through four to five cycles per night, and the duration of the REM cycle increases with each cycle. Different patterns of activity in various brain regions characterize these parts of the sleep cycle. In stages one and two of NREM, you are very lightly sleeping and may have fragmented memories. People in these stages are very easy to wake up.

Stages three and four of NREM are considered deep sleep, with greatly decreased brain activity. Following these stages, you will enter REM sleep, in which patterns of brain activity change and dreaming occurs. The exact purpose of REM sleep is unknown, but infants spend a much higher proportion of their sleep cycle in REM, which suggests a role in brain development. Drugs like alcohol, caffeine and nicotine can interfere with REM sleep, which can make you feel more tired the next day. So if you normally have a drink or two before bed, try to eliminate this and you will sleep better.

As I mentioned, scientists are still investigating what happens during sleep and why it is so important for people and other animals to get enough of it. For obvious reasons, it is not that easy to study what is going on inside the brain of a sleeping person and most of our knowledge comes from MRI and other imaging studies. One mechanism that seems to be involved is called synaptic plasticity. The brain is constantly being remodeled as a result of experiences, with connections between neurons being strengthened or weakened. Additionally, from birth to adolescence, a special type of plasticity called synaptic pruning occurs. This process is responsible for eliminating all of the unneeded connections in the brain at birth so you can focus your energy on the important ones. There is evidence that synaptic pruning, as well as other forms of plasticity, largely occurs during sleep, when the brain is in a resting state.

This could be a reason why children and adolescents need more sleep than adults – they need extra time to reorganize brain circuits that are fully established in adulthood. It is of paramount importance that children and teenagers get enough sleep; if they don’t, their brains may not develop correctly and they are much more likely to develop mental disorders down the road. In addition to synaptic, other forms of plasticity are important for the establishment and consolidation of long-term memories. People who are sleep-deprived perform worse on tests of memory and cognition. Whatever the specific processes implicated, it is clear that proper sleep is crucial for normal brain function.

The timing of your sleep is extremely important in maximizing its benefits. This is due to natural fluctuations in chemicals, hormones and metabolic processes throughout the 24-hour cycle known as the circadian rhythm. These patterns are observed in a huge variety of organisms, from primitive, unicellular cyanobacteria all the way to humans. This suggests that a circadian rhythm is an extremely beneficial adaptation.

This is not at all intuitive and much remains to be understood, but a proposed theory is that cyanobacteria evolved the adaptation so that they could protect their DNA from damaging UV light during the day and replicate it to reproduce at night. Circadian rhythm machinery doesn’t depend on environmental factors, but it can influence it. So a group of people put in a dark room for 24 hours will still exhibit a circadian rhythm, but alterations in certain factors such as light will reset the rhythm.

A great example is jet lag. After a long east-west flight, you don’t feel too great, but within a few days you will adjust and have normal sleep patterns and behaviors. Each person has a slightly different circadian rhythm. To find your optimal bedtime and wake up time, I’d suggest that you do some experimenting.

Sleep is largely still a mystery to scientists and probably will be for many years until we develop better techniques to study it. But for now, it’s safe to say that you need to get good sleep to function, and that without it, everything will start to deteriorate. Maybe someday we will understand the intricacies of sleep, and even develop ways to live without it, but for now we can only dream.