Do you get enough sleep? Chances are you dont. Many people living in modern industrial societies suffer from a chronic, and worsening sleep deficit.

Until a few decades ago, most people lived lives so very different from ours that we would scarcely recognize them. Until fairly recently in human history the majority of people lived in small villages or on farms, not in big cities. There were no electric lights. There werent any faxes or e-mails. There was no Internet, and no television. Once the sun went down, most of the days activities came to an end.

People worked very hard physically, and only a very small minority had what we would call white collar jobs. And most people, on average, slept nine to nine and a half hours each night.

For most of us today, an average of nine hours sleep each night is an impossible dream. In our very busy schedules, something has to give, and quite often the choice many of us are making is to cut back on our hours of sleep.

If you listen to, or read some of the popular current guides to success, you will usually be instructed to work hard, play hard, study hard, be more outgoing, and gain every advantage you can. The struggle to the top can be ruthless. Why, even the struggle to stay where you are and not to lose your place can be ruthless.

Where do many of these success guides and gurus tell you to cut back? Why, on your hours of sleep. Theyll tell you that sleeping more than five or six hours a night is a waste of time. Theyll tell you that the world is moving ahead while you are dozing, and that youll never catch up if you indulge your desire to sleep. If you snooze, you lose!

Theyll tell you that you dont really need those extra two or three hours of sleep each night. That its just a bad habit youve developed. That its self-indulgent. That a full nights sleep is the booby prize for losers in the game of life.

Unfortunately, this advice goes against thousand of years of human biology.

Its true that some of us really do need only five or six hours of sleep each night, but those people are in a minority. Most of us require seven, eight, or even more hours of good quality sleep every night in order to function at our best intellectually, physically and emotionally.

In sleep deprivation experiments conducted on volunteers, it has been found that even a few days of sleep loss produce a marked negative effect on a persons mental abilities. It becomes much harder to focus mentally and to process information. Decisions take longer to make, and are of poorer quality. Learning and remembering new information becomes more difficult, and it becomes harder to recall information that was previously learned. Creativity declines, while mistakes increase.

A person who hasnt had enough restorative sleep will have difficulty handling technical machinery. In addition, lack of sleep causes emotional impairment and difficulty with mental processing. As people become more sleep deprived, they may experience more depression and mood swings. Tempers flare more often, and sleep deprived people become less cooperative with others.

Lack of sufficient sleep is believed to have contributed to many well-known accidents, such as the explosion of the Challenger space shuttle, the near meltdown at Three Mile Island, and the nuclear disaster at Chernobyl. It is believed that lack of sleep contributed to poor decision making in each of these incidents, with disastrous results.

If you add to these examples the many hundreds of thousands of other accidents every year caused by sleep deprivation, it becomes clear that cutting back on our sleep may not really be the solution for greater productivity we are looking for.

If you are studying for important exams, you will be better off getting sufficient sleep the night before, rather than spending the whole night desperately trying to cram more information into your head. Remember that your brain uses its sleeping hours to process the information of the day and to consolidate new memories. Cutting back on sleep in order to study instead will interfere with this process.

How can you tell if you are getting enough sleep? The ideal amount varies from person to person, and it is not always the same.

Ask yourself: When you wake up, do you feel refreshed, or is your body longing for more sleep? Do you rely on a lot of coffee to get you through the day?

There are steps you can take to improve the quantity and quality of your sleep. The first step for most of us is to examine how much caffeine we consume in a day. Caffeine is a stimulant found in coffee, tea, and many types of cola. It is also present in many over-the-counter medications. Caffeine enters the bloodstream very quickly and its stimulative effect lasts several hours. If you are have a hard time getting settled down at night, it could be due at least in part to an excess of caffeine throughout the day.

If you are not getting enough good quality sleep, make the effort to cut your consumption of caffeinated beverages to just one or two cups a day, or stop drinking caffeine all together. In order to have a more restful evening, dont drink anything caffeinated after lunch. There are plenty of beverages without caffeine that you can substitute. For most people, a cup of warm milk before bedtime will promote sleepiness.

Some of us are physically addicted to caffeine and will actually go through withdrawal symptoms if we try to cut back, or quit using it altogether. You may find that when you stop ingesting caffeine, it takes up to two weeks to get over your physical craving for it. In the meantime you may experience headaches, dizziness and insomnia.

Another factor that can disrupt your sleep patterns is the consumption of alcohol. Although alcohol initially can make you drowsy, it suppresses the REM stage of sleep, which appears to be essential in restoring a sense of wellbeing.

There are many other possible causes of poor sleep. If poor quality sleep is a problem for you, it will be worth the effort to become a detective and track down the cause. Often the problems of poor sleep can easily be fixed.

A poor quality mattress will lead to poor quality sleep. So will poor ventilation in your bedroom. Or too much light. Or too much noise. Or a television set.

Are you getting enough exercise? Most of us today do not move our bodies nearly as much as our bodies were designed to move. If we have an office job we are often so mentally fatigued by the time we get home that we dont want to get off the couch. Our brains may be exhausted, but our body still needs exercise. Have you ever gone to an exercise class, thinking at the beginning, I dont really want to be here, but once you got moving you felt great? A lack of sufficient physical exercise will lead to poor quality sleep. However, vigorous exercise too close to bedtime can leave you too stimulated to sleep.

Sleep experts advise:

Keep a regular schedule for sleeping.

Maintain a comfortable, restful bedroom.

Dont use your bed for anything other than sex and sleep.

Dont have the television in your bedroom.

Get at least half an hour of physical exercise a day, preferably outdoors.

Slow down your physical and mental activities as bedtime approaches.

Cultivate a relaxed, calm state of mind at all times, but particularly before bedtime.

Avoid shift work.

Avoid stimulants or alcohol before bedtime.

If you try all these recommendations and you still feel that you are not sleeping well, you may have a medical condition that interferes with the quality of sleep you are getting, or you may be taking medication that interferes with your sleep.

For example, if you always wake up feeling exhausted, you may be suffering from a medical condition such as fibromyalgia, or sleep apnea. If you find yourself waking up in the middle of the night, anxious and unable to sleep again, this can be caused by depression or stress.

These are conditions that should be discussed with your doctor.