The Most Productive Third of Your Life

- November 12, 1999

Sleep is needed to rejuvenate the body and mind. What is the most important part of sleep? Too little sleep can be very detrimental to your health.

By Igor Rybinnik
Spectator Staff Writer

Reprinted with permission granted by
Columbia Spectator
Columbia University, NY, NY

People spend one third of their lives in an altered state of consciousness. This is required for normal growth and development, and it plays a significant role in maintaining the body's normal functions. I'm talking, of course about the rejuvenating and soothing activity we call sleep.

Sleep is associated not only with relaxation, regeneration of the body's tissues, and sorting of information accumulated during the day, but sleep also gives us the strength to face each day's worries, concerns, and problems.

The human body is generally governed by a 24-hour biological clock known as the circadian rhythm. Many psychologists think of sleep as an altered state of consciousness that is an important part of the biological cycle. During this altered state, information is processed unconsciously. Sleep progresses in a sequence of stages about 90 minutes in length that repeat several times throughout the night. The first several stages are marked by a slowing of the metabolism and muscle relation.

However, in the later stages, especially once Rapid Eye Movement (REM) sleep sets in, heart and breathing rates rise and eyes begin to dart about sporadically, signifying the beginning of a dreaming period. It is during REM sleep that the brain is most active, with the amount of activity at times reaching waking levels. Paradoxically, the brain's motor cortex controlling movement is active while the muscles are essentially paralyzed. Thus, internally the body is aroused, while externally it is calm.

The Deepest of Sleep

One cannot be easily awakened during REM sleep. The brain would be required to drop whatever it is doing and suddenly begin interpreting excessive information from the senses. This might explain the fact that we often feel disoriented and exhausted when an alarm clock awakens us in the middle of a dream.

Why do we need sleep? A significant reason seems to be that sleep possesses recuperative powers. During sleep, metabolism is lowered and available resources are diverted to restoration of the body's tissues, especially those of the brain. Because people waste less energy for exhausting muscle operations and digestion, the body is able to use that energy to repair itself. This may explain why some headaches are alleviated with even a short nap. Moreover, sleep also plays a role in the growth process because during sleep the pituitary gland releases a growth hormone.

While we sleep the brain processes sensory and conceptual information accumulated during the day. This information is sorted and new neutral connections are made to accommodate newly forming memories. Dreams seem to fit into the information processing theory of sleep. Sigmund Freud believed that dreams uncover and gratify unacceptable impulses. However, according to the newer dream theory, dreams, especially those occurring at the beginning of the night, often incorporate experiences and preoccupations from the day's events. Thus, having spent an evening studying organic chemistry reactions, you are likely to see chemistry entering your dreams.

How much sleep do we really need? Humans have no absolute daily requirement of sleep. The optimal amount varies from one individual to another. In Fact, our own bodies tell us when they need rest. Usually, one feels lethargic in the early morning hours and in the late afternoon. According to the 1997 study conducted by Cynthia May, Ph.D. of College of Charlston and Lynn Hasher, Ph.D. of Duke University, undergraduate students experience their daily peak in circadian arousal in the evenings. Adults, on the other hand, usually find themselves to be morning persons.

Sleep Needs Vary

In general, one should sleep enough to maintain optimal alertness during the day. For a typical college student, the sleep requirement is six to 10 hours a night. According to Dr. Stanley Coren a professor of Psychology at the University of British Columbia, undisturbed, humans tend to sleep nine to 10 hours a night. For normal functioning, it is essential to get at least several hours of uninterrupted information-processing REM sleep. For people who have trouble falling asleep, alcohol and sleeping pills may aggravate insomnia because they actually reduce the effective amount of REM sleep.

Sleep deprivation has adverse, although temporary effects on our body's biological and psychological state. Fatigued college students who fall asleep during lectures would agree that lack of sleep tends to make them more unfocused and lethargic.

According to psychologists Beardsley and Irwin, sleep loss is linked to suppression of the disease-fighting immune system. The effectiveness of killer cells that combat viral infection decreases noticeably. Impaired creativity and concentration, irritability, and diminished performance are among other significant effects of sleeplessness. After staying awake for 11 days and setting the Guinness Book of Records sleep deprivation record, 17- year old Randy Gardner experienced hallucinations and speech and movement problems.

However, when catching up on their sleep, most people experience a REM rebound phenomenon where the amount of REM sleep per night increases, and they literally sleep like babies. Thus, after sleeping for 15 hours, Randy awoke feeling fine. Also, 15-to-20 minute naps seem to be beneficial, improving alertness, sharpening memory, and reducing fatigue.

Sleep is biologically and psychologically refreshing. When someone gives you the advise to sleep on it and assures you that you'll feel better in the morning, they are probably right.