You cannot buy it, borrow it or steal it. But - oh, bliss - if only you could. In these harried times, having enough has become the ultimate luxury. Sleep - free and easy sleep without the interruptions of children, snoring or 2 a.m. anxiety attacks - is the elusive holy grail of modern life. Who doesn't yearn for another hour in the day? Or envy those who can cope on four or five hours of nightly nodding while maintaining a whirlwind schedule? "I'll catch up on sleep when I die," people say, blithely ignoring the common sense truth that their growing sleep deficit may lead them to the grave sooner than they had expected.
Sleep and stress are two sides of the same coin. The less well you acknowledge and handle daily stress, the more likely you are to lie awake at night or to sleep fitfully, grinding your teeth and rattling your bones. Shiatsu, massage, aromatherapy, a daily walk, lying down and listening to music . . . any of these can bring about a better night's sleep. Every human body has its own biological rhythm of sleeping and waking. Lark-types are perky in the morning and feel themselves dipping at night. Owl-types feel energised at night and must force themselves to face the day. Just why we are like this is not yet fully understood, although there is probably a strong hereditary component.
Most of us - the lucky ones - are brightest in the morning, then take a dip after lunch at some point between 1 p.m. and 4 p.m. The soporific effect of a midday meal, especially if as little as one unit of alcohol is involved, can be so powerful that some people are unable to work effectively and might as well call it a day. Skipping lunch or dining very lightly is a survival mechanism for those who fade after lunch. In the US, 20-minute power-napping is now considered socially acceptable in the office because it makes workers more efficient. Nap or no nap, most people manage to re-energise in the afternoon. Then the early evening brings a gradual, pleasant feeling of relaxation and sleepiness to which, ideally, we succumb at some point between 10 p.m. and midnight - and preferably as soon as our heads hit the pillow. The average amount of sleep most people need to feel rested is between seven-and-a-half and eight hours, with women generally needing 15 minutes more. Some people need nine hours of sleep while others genuinely thrive on five.
More sleep isn't necessarily better sleep. It's the quality that counts. Yet while the body knows what kind of sleep it needs, many of us are constantly overriding our instincts and overcoming feelings of physical exhaustion in order to accomplish more in the day. We're our own worst taskmasters, packing careers, commuting, leisure, child-rearing, housework, shopping, cooking and eating into punishing schedules. The bad habits which come from a stressful lifestyle are a guarantee of poor sleep. Eating late, drinking too much alcohol or coffee, engaging in little physical exercise or becoming accustomed to sedatives, can all disturb sleep.
Most of us are wandering around in a states of chronic sleep deprivation, believes Dr Stanley Coren, Canadian author of Sleep Thieves. He claims that for every hour of sleep lost in a night, we drop one IQ point the next day. In a week of five- to six-hour nights, the average person could drop 15 IQ points, turning someone of normal intelligence into a marginally functioning wreck.
AS anyone who has experienced it knows (and who hasn't?) fatigue makes you feel physically weak, irritable, demoralised, depressed and even physically unwell with aches and pains. Most of us survive with no harm done by operating on automatic pilot, although the consequences can be deadly. It is well-known that industrial accidents are more likely to occur during night shifts and that one-vehicle car accidents usually occur in the dead of night - which is called that for a reason. More deaths occur during the early hours than at any other time of the day.
One-third of people complain of sleep problems and fatigue is in the annual top 10 complaints seen by GPs. In one study of a primary care practice in the US, nearly one-quarter of patients said they had a problem with chronic tiredness. Fatigue is endemic, it can begin early in life and last a lifetime. Dr Benjamin H. Natelson, author of Facing and Fighting Fatigue: a Practical Approach (Yale University Press), argues that problems with sleeping, and the consequent chronic tiredness, should be seen as personality traits, like cheerfulness or pessimism. Women are more likely to be sleepless than men. Whether a study is performed in France, England, or the US, fatigue is always found to be approximately 50 per cent more common in women than in men.
In a perverse way, the very insidiousness of sleep deprivation should make us feel better. When you are lying awake at 2 a.m. counting the minutes, there is nothing worse than feeling the rest of the world is slumbering peacefully. In pre-industrial times, this period of semi-wakefulness was called "the watch", and many artists and scientists have been known to find their greatest inspiration during the small hours. In our electrified modern world, we live our lives according to strict schedules, going to bed at the same hours in summer and winter, regardless of nature's hours of darkness. We lose patience with ourselves and expect our bodies to obey the sleep command, even when nature is telling us to do otherwise. When left to sleep naturally, people tend to sleep longer in the winter - as long as 14 hours - and as little as six hours in the summer.
The lying-awake feeling, which can drive you demented, is as much a product of our own expectations as it is of a true lack of sleep. Studies of people who call themselves "insomniacs" have found that nobody truly lies awake all night. Insomniacs asked to bed down in sleep laboratories for scientific purposes have been shocked the next morning to see videotapes of themselves snoring soundly. The perception of getting little sleep may be due to the fact that you have to be asleep for 10 minutes before your body "knows" it has been asleep. "Insomniacs" may fall asleep and reawaken throughout the night while perceiving only their wakeful periods.
There's no doubt, though, that poor sleep can make you feel debilitated the next day. A restorative night's sleep has its own architecture, comprised of two basic forms: sleep occurring during rapid eye movements (REM sleep) and sleep occurring in the absence of REMs (non-REM sleep). When a healthy person falls asleep, the sleep becomes progressively deeper until about 90 minutes later, when sleep lightens and becomes REM sleep. While the sleeper may move around during the initial stages of sleep, motion stops when REM sleep begins and instead of the body moving, the eyes dart back and forth beneath lids. The cycle repeats itself, with the REM periods occurring closer together towards morning. The best, deepest, most restorative sleep happens during the first third of the night - backing up traditional wisdom that an hour before midnight is worth two after.
Any disruption of the normal sleep pattern results in sleepiness, and the most common causes of this disruption are anxiety and stress. It is human nature for people to ignore the fact that they are stressed during the day, only to have stress rear its ugly head in the middle of the night. So while you may be tempted to focus on your bedroom habits in trying to improve the quality of your sleep, you should also examine your waking life for the answers to a good night's sleep. Building physical exercise and relaxation into your day - in whatever form - will have benefits at night-time.