By Henrylito D. Tacio
“The vigorous are no better than the lazy during one half of life, for all men are alike when asleep,” Greek philosopher Aristotle, one of the most influential thinkers of the ancient world, once said.
To which English poet, essayist, and critic added: “Oh sleep! It is a gentle thing, beloved from pole to pole.” William Shakespeare, one of the giants of world literature, penned: “Sleep that knits up the ravell’d sleeve of care.”
“Sleep is an acquired habit,” commented American inventor Thomas Edison. “Cells don’t swim. Fish swim in the water all night. Even a horse doesn’t sleep. A man doesn’t need any sleep.” Science fiction writer Isaac Asimov agrees when he once said, “I never use an alarm clock. I can hardly wait till five A.M. In the army, I always woke before reveille. I hate sleeping. It wastes time.”
Everyone, it seems, has an idea about sleep or lack of it. But until now, no one yet knows exactly why we sleep or how much we really need to sleep. “Sleep is necessary for survival and good health, but why sleep is needed or exactly how it benefits people is not fully understood,” The Merck Manual of Medical Information notes.
Just a century ago, sleep was considered little more than a nightly vegetative state, a time when daily pursuits were still for eight to 10 hours. The brain temporarily ceased to function, and the body disengaged, entering into total, quiet rest.
In the 1930s, with the first use of electroencephalogram (EEG) – an electronic brain-scanning device – the doors to understanding sleep commence creaking open. But not until 1953, when scientists verified the phenomenon of rapid eye movement (REM) during sleep, did the field of sleep science become established.
REM is a period of intense brain activity, often associated with dreams, when body temperature and blood flow increase and voluntary muscles are paralyzed; it occurs regularly about every 90 minutes. “The discovery of the existence of REM offered first proof that in sleep the body is not at total rest,” write Charles B. Inlander and Cynthia K. Moran in their book, 67 Ways to Good Sleep.
“Sleep is a natural period within every 24 hours when the body repairs itself, tests its systems, consolidates memory, purges itself of cellular waste, and stockpiles energy for the day ahead,” explains Inlander and Moran. “On average, humans spend about a third of their lives asleep, or about 205,000 hours in a 70-year lifetime.”
Diane Hales, the author of How to Sleep Like a Baby, explains that when you sleep, “you are not motionless like a car in a garage. (Sleep) is an altered form of consciousness, when muscles tense and relax, your pulse, like the temperature and blood pressure, rises and falls, the brain works, and chemicals course through the bloodstream.”
Sleep is not a uniform state; it has several distinct stages through which it normally cycles five or six times every night. The home edition of the Merck manual explains: “Sleep progresses from stage 1 (the lightest level, during which the sleeper can be awakened easily) to stage 4 (the deepest level, during which waking the sleeper is difficult). In stage 4, the muscles are relaxed, the blood pressure is at its lowest, and the heart and breathing rates are at their slowest. Besides these four stages, there is a form of sleep accompanied by REM and behavioral activity.”
During REM sleep, electrical activity in the brain is unusually high, somewhat resembling that of wakefulness. In REM sleep, the rate and depth of breathing increase, but the muscles are greatly relaxed – more so than during the deepest levels of non-REM sleep.
“Most dreaming occurs during REM and stage 3 sleep, while most talking during sleep, night terrors, and sleepwalking occur during stages 3 and 4,” the Merck manual says. “During a normal night’s sleep, REM sleep immediately follows each of the five or six cycles of four-stage non-REM sleep, but it can occur at any of the stages.”
How Much Sleep?
But the question that really bugs most people is how much sleep does an individual really need? “As with hair color and height, the amount of sleep a person needs differs by individual physiology, by age, and, at times, even by gender,” Inlander and Moran write in their book. “Adult sleep needs range from five to 10 hours a night, with the average adult needing between seven and eight hours. Statistics show that only one person in 1,000 can get by on fewer than 4.5 hours of sleep.”
Recent studies on sleep needs by age-group versus what each group is actually getting, bare that:
· Babies need and receive 18 hours per day.
· Young to pre-teenage children needs and generally receive 10 to 12 hours (eight after they stop napping).
· Teens need up to 10 hours and an average of six.
· Adults need an average of seven to nine hours and get fewer than seven.
· The elderly need about eight hours and get five to seven (some a bit more with naps).
“But these figures are simply averages,” Inlander and Moran point out. “They may not apply exactly to you.”
So, here’s a simple home test suggested by health writer Joan Barbato: “You are probably not getting enough sleep if you frequently: are drowsy when driving; get into accidents; are irritable; have impaired memory; have difficulty making decisions; wake up tired; feel your productivity diminish; sleep longer and feel better when the weekend comes.”
Loss of sleep accumulates, so sleep debt, or deficit, is the cumulative total of sleep hours you are behind. Stanford University’s sleep-research pioneer William C. Dement told Family Circle: “Until you sleep, that debt remains unsatisfied in the same way that you’re thirsty until you drink.” In other words, you can resist, but eventually, the debt will overwhelm you.
The good news? A reasonably healthy human is remarkably resilient and is able to reduce or repay a sleep debt with just a little concerted effort. “Even if the person’s missed all sleep for 10 days,” notes Mayo Clinic sleep expert Peter Hauri in No More Sleepless Nights, “a sleep of 14 to 18 hours a day for three days followed by returning to a normal schedule will eliminate the debt.” The typical formula, according to experts, is: One hour of sleep can repay two lost hours of sleep.
So, You Can’t Sleep?
If you can’t fall asleep, experts advise that you set a rigid sleep schedule seven days a week. “Sleep is an unavoidable interval in the 24-hour day,” says Dr. Merrill M. Mitler, director of research at the Scripps Clinic and Research Foundation in La Jolla, California. “We insist on people trying to be as regular with their habits as possible.”
The key is to get enough sleep so you can make it through your day without drowsiness. To help achieve that goal, try to get to bed at the same time each night so you can set your system’s circadian rhythm, the so-called body clock that regulates most internal functions. Just as important is arising at the same time each morning.
Go to bed only when you’re sleepy, advises Dr. Edward Stepanski, director of the Insomnia Clinic at the Henry Ford Hospital’s Sleep Disorders and Research Center in Detroit, Michigan. If you can’t fall asleep in 15 minutes or so, get up and do something pleasantly monotonous. Read a magazine article, not a book that may engross you. Knit, watch television or balance the checkbook. Don’t play computer games that can excite you or perform goal-oriented tasks such as laundry or housework.
When you feel drowsy, go back to bed. If you can’t fall asleep, repeat the procedure until you can. But remember: Always wake up at the same time in the morning.