Think of the day before you had a mid term exam. Maybe you stayed up all night studying the subject which would be tested tomorrow. But you maybe were so anxious for not sleeping because it may lead you to forget things you memorized. But there were so many things to study, so you couldn't but stop studying.
Sleep. It seems like it will always compete with our will. We often struggle against sleep incessantly. Furthermore, we are the university students who can organize our own class schedule voluntarily and there's no warning if we are late or absent, though our name will be checked on the attendance book. We can be lazy as long as we want. Then why do we need sleep and how many hours of sleep would be good? Now we will dive into the world of sleep.
There's a saying about sleep which you've heard many times. That is 'You can memorize things better when you sleep after studying hard.' But is it true?
Let me tell you a little theoretical story because we need a foundation knowledge to talk about the relation between memory and sleep.
First, what do you think about sleep? We need sleep. Sleep is a physical reaction which gives rest to your brain by decreasing the sensory stimulus. There are two types of sleep; REM sleep and non-REM sleep. Our sleep starts with non-REM sleep and consists of 4 stages. Right after non-REM sleep, REM sleep starts. It takes up 20 % of the whole sleep and it repeats from five times to seven times.
Along the physiological theory, it is assumed that REM sleep stage is related to our powers of memory. Then in what situation are we during the REM sleep? Very magically, we have rapid eye movement (That's why we call it REM sleep) and our respiration increases like the state we are awake. And when we are roused from REM sleep, we usually have a dim consciousness. In other words, it is connected with deep sleep. It is believed that synapse which will transport our signals (like facts we study) from brain is synthesized during REM sleep.
Furthermore, REM sleep is relevant with our life span. The average term of REM sleep of women is 70 minutes and for men 40 minutes. As you know, women live longer than men by about 6 years. And if we awaken mice during their REM sleep, they can live only 5 months though their average life span is 2~5 years.
Then you can think sleep is certainly a very important activity relating studying and the length of life.
By this time, maybe you are concerned about 'How many sleep hours would be good' The writer of 'Early riser', Hiroshi Saisho said in his book that 'The whole cycle of non REM sleep and REM sleep is 2 hours, so with 3 cycles, it become 6 hours, and 4 cycles, 8 hours. Therefore, it is good to set even hours concerning the cycle. But the author of 'Science of dream', Hurtman said the person who sleeps for a short time is fast asleep and has a deep sleep. So 6 hours is better than 8 hours. '
But as you know, when the test is around the corner, we may need to decrease our sleep below 6 hours. Then let's find a way to sleep shorter.
Many drinks, such as coffee or green tea, contain caffeine. Caffeine makes us stay in a arousal state. But later caffeine shows toxic symptoms so you should be careful.
If you want to reduce your sleep time, you have to stay your brain aroused. For instance, when you wash your face with cold water or expose yourself to the wind, your brain is startled and becomes awaken. But you'd better sleep for concentration for 15-20 minutes.
Sleep is an essential thing but a necessary evil during the exam term. We need to cope with sleep wisely. Making use of theories, when you need to sleep for minimum hours, you'd better choose an even number of hours. And remember the 2 hours of the whole cycle. Don't be awaken during the REM sleep. Also, when you don't want to sleep, keep your brain cool and stimulate it. Drinking coffee and caffeine is another way.
Then everybody, by regulating your sleep hours wisely, good luck on your exams!
By Kim Moon-sun
Culure reporter