Researchers maintain a constant seven to eight hours of daily sleep throughout the year. However, researchers in America tend to take a different view. They assert that because most of us can extend our daily sleep, we must need to do so. This would mean that people who seem content with seven and a half hours of sleep a day during the week but enjoy nine hours at the weekend are, unknowingly, chronically deprived, and actually need nine hours every day. Evidence for this is said to come from the many people who are sleepy in the daytime.

When we drift off to sleep, we either fall into a deep, restful sleep, or into a shallow, light sleep. It becomes obvious that if you experience a deep sleeping for few hours, it will be better than sleeping for long hours while experiencing a shallow sleeping as you will find yourself very tired, and your body is exhausted when you wake up.

Napoleon Bonaparte, who was not a good sleeper, had advocated ?six hours sleep for a man, seven for a woman and eight for a fool?

Many studies make it clear that the amount of sleep each person needs varies and depends on many factors, including age. Infants generally require about 16 hours a day, while teenagers need about 9 hours on average. For most adults, 7 to 8 hours a night appears to be the best amount of sleep, although some people may need as few as 5 hours or as many as 10 hours of sleep each day. Women in the first 3 months of pregnancy often need several more hours of sleep than usual. The amount of sleep a person needs also increases if he or she has been deprived of sleep in previous days. Getting too little sleep creates a "sleep debt," which is much like being overdrawn at a bank. Eventually, your body will demand that the debt be repaid.