Humans Need Enough Sleep

The claim that sleeping strengthens the immune system and is an integral element to maintaining life has been widely appreciated in recent times.

According to an experiment on mice carried out by Allan Rechtschaffen, professor emeritus of psychiatry at the University of Chicago, mice that are deprived of sleep for 2 weeks lose skin elasticity and weight. After 3-4 weeks, they even lose the unique ability of mammals to regulate body temperature. Even though the mice were well fed, they eventually died when their immune systems weakened, looking as if they had been starved.

Although on the same diet, those which got enough sleep remained healthy, maintaining their weight.

How does sleeping affect life?-

The standard Korean dictionary defines sleeping as a state in which humans rest “with all activity of consciousness stopped and their eyes closed.” As such, many of us believe that human brain activity stops once we fall asleep like we turn off the light, and as we wake up, the brain resumes its activity.

Reality does not seem to match our common belief. Relevant researches in the field have shown that the human brain works while we sleep. Eugen Aserinsky, PhD, and Nathaniel Kleitman, PhD, of the University of Chicago published findings in 1953 that human brain waves continue to move for a certain period of time after we fall into sleep, with regularly occurring periods of eye motility (REM).

Subsequent research has revealed various aspects of sleep. Humans always have dreams while sleeping. This is quite natural given that human brain continues to be active during sleep. According to Allan Hobson, Professor of Psychiatry, Harvard Medical School, when we dream, only the part of the brain controlling emotion is active, while the part controlling memory and logic is not. Thus, humans cannot remember that they had a dream once they wake up. Only when they are woken from a nightmare are they able to remember their dreams. People also tend to believe their dreams are black and white. Yet this is because humans cannot remember, even though they do have colorful dreams.

Freud, who said that dreams are a source of insight into the unconscious mind and hidden sexual desire, is likely to be wrong. People might want to believe that dreams signify the unconscious mind or tell us something about the future. Yet this is unlikely to be true. During sleep, the brain actively organizes information and deletes unnecessary memory. New experiences gained are consolidated to update your memory. Thus, staying up late to study may not make your grades better, as you need enough sleep to consolidate the information that you learned during the day.

The human brain during sleep is not as active to the same degree as during the time one is awake. When sleeping, the parts of the human brain that control our motion are inhibited. This explains that even if you have a dream in which you fall off a cliff and run away from something, your body does not move. During sleep, those parts of human brain that regulate our logic and judgment are not active either.

It is important to notice that during sleep a human’s emotional ability is strengthened. Humans need to know when to come forward to others, when to run away, and when to make a relationship for their survival.

Modern society, however, inherently deprives humans of sleep.

Jeong Do-eon, professor of psychiatry at Seoul National University, says, “People living in this modern society are under constant stress from numerous sources, such as interpersonal relations, promotions, lay-offs, and exams, to name a few. Combined with coffee and other sources of caffeine that people ingest during the day, we are left with less sleep than we need. The Internet and drinking are also factors that take away from the amount of healthy sleep we need.”

artemes@donga.com