The secrets of sleep
By Mohinder Singh

MOST people overeat 100 per cent, and oversleep 100 per cent, because they like it. That extra 100 per cent makes them unhealthy and inefficient."

The man who wrote these words in his diary was Thomas Alva Edison, the man who invented the electric bulb. Once the bulb banished darkness, the average person’s sleep time of 9 hours each night came down by one-and-a-half hour.

How much sleep do we need? All of us sort out this question for ourselves. Society lauds those who are known to cut down on sleep for work. But then we have to balance the same against our individual requirement of sleep.

First, the fundamental question: what is sleep? Why should we spend one-third of our lives on this unproductive activity? A 60-year-old person, for example, has spent at least 20 years asleep. No human or animal has been shown to be able to dispense with sleep or survive without it.

Sleep is a process that is so important to the physical and psychological well-being of living things that nature has gone to inordinate lengths to allow sleep. Some birds can sleep while in flight. Some fish can sleep while swimming. A giraffe takes up to a minute to get up, uncurling those lanky legs. During this time the animal is completely unprotected. To place the giraffe in such a position of vulnerability each day, sleep must be very important indeed. "If sleep does not serve an absolutely vital function, then it is the biggest mistake the evolutionary process has made," says Dr Allan Rechtschaffen, a sleep researcher at the University of Chicago.

But what is sleep for? This is the most embarrassing question one could ask a sleep expert. Many theories have been formulated; yet why we sleep remains an enduring mystery. In small mammals, sleep may save precious energy (in lowering the thermostat sleep conserves energy and the need for food) when the prospects for foraging are not good, but in other species this explanation is not satisfactory. In despair, some have suggested that sleep may simply have kept our ancestors out of trouble at night.

There are elegant theories that dwell upon the importance of dreaming (REM sleep), as well as the non-REM phases of sleep. Incidentally, despite popular claims to the contrary, there is very little support for the notion that we may learn anything during sleep, whether in non-REM or REM sleep.

Poets, artists, and common folk alike have always assumed that sleep is rest for both the body and brain — welcome period of recovery, whether from physical or mental exertion.

"O sleep! O gentle sleep!
Nature’s soft nurse..."

Shakespeare in Henry 1V.

Yet, a simple observation suggests that sleep is, in its essence, for the brain. If we lie awake but immobile for an entire night, in the morning our muscles are relaxed but our mind is not, and our sense of well-being is lost. A waking brain is conscious. Sleep, or perhaps certain phases of sleep may offer the blessing of unconsciousness or at least the liberation from the tyranny of memory.

Can we change our sleep habits? Veteran sleep reseacher Dr Wilse B. Webb of the University of Florida answers: "I spent five years of my life trying to prevent nocturnal rats from sleeping during the day, and they spent five years teaching me I was rather foolish." There is a deep, inherent system here, and we cannot change it. Though human being can alter their sleep temporarily, they return to a sleep budget that seems genetically fixed.

"Some people think they don’t move at all in sleep," says Dr J. Allan Hobson, professor at the Harvard Medical School. "They swear to you that they go to bed and never change position. Not true. My studies show that everybody makes at least 8 to 12 major posture shifts at night. Insomniacs may double or triple that."

Too many movements constitute "tossing and turning" and make for poor sleep, but too few shifts — sleeping like a log — may be worse. Alcohol, for one, inhibits movement. Someone drunk to stupor risks paralysis in sleep. You can kill a nerve in one night just by lying on it — for example, the radial nerve in the upper arm.

As you are, so shall you dream. "Dreams are messages to ourselves," says a sleep reseacher. Women’s dreams have more people in them than men’s, possibly because women keep closer touch with friends and family — they are the ones who remember birthdays. Curiously, men dream more often about other men than about women, who tend to dream of the sexes in equal proportions.

Contrary to popular belief, the need for sleep does not decrease with age. Again, trouble staying awake during the day should not be accepted as a normal part of getting old. However, people in the 60s and older start to feel sleepy earlier in the evening — as if the brain had moved forward a few time zones. And they wake up correspondingly early. That way, late nights aren’t the ones for older people.

There’s the ageold conventional wisdom that the best thing you can do when you’re sick is to go to sleep. This now gets strong support from some scientific findings. It has been discovered that the chemicals released in the brain to influence sleep have profound effects on immune-system activity. On the other hand, a loss of sleep causes a decline in several measurements of immune function. Within minutes of falling asleep, natural killer cells in the blood start performing antiviral and anticancer surveillance, say some researchers. Does sleep per se have recuperative powers, scientists aren’t sure.

After the common cold, difficulty with sleeping is perhaps the most prevalent health complaint, ranging from transient insomnia to dreaded narcolepsy. There are more than 50 sleep disorders, the prominent ones: head banging, sleep walking, nightmares, SIDS (Sudden Infant Death Syndrome), teeth grinding, restless legs syndrome, apnea, snoring, and other breathing disorders.

The largest complaints, of course, are about insomnia, a mask for many conditions. Insomnia itself is not an illness but a symptom of some other disease or problem. The leading contenders are anxiety, drug or alcohol dependency, or psychiatric disturbances. Often, the difficulty begins during a time of stress but lingers after the crisis has passed.

Strangely, a significant percentage of insomniacs sleep soundly when under observation in sleep clinics. Even when they are woken up sleeping, they make out they were awake. "We know of no one who has died of it," says a sleep therapist, offering consolation.

For double-bed couples, every sleep disturbance is a shared one and, if you add duvet wars, the disruptions of small children, different body temperatures (fit people are hottest), not to mention snoring, groaning, scratching, lip-smacking, nose-whistling, clucking, kicking, the case is unarguable: Whosoever sleeps alone sleeps best.