Insomnia

The Facts

Sleeplessness is a very common experience for many people. While the classic form of insomnia involves lying in bed unable to get to sleep (called initial insomnia), the problem can take other forms. Some people wake up earlier than they'd like in the morning, and can't get back to sleep (early morning awakening). Others can sleep fine during the day, but not at night. This is called sleep rhythm reversal.

A common problem is delayed sleep phase syndrome. People with this syndrome have a "body clock" that takes more than 24 hours to go through a cycle. They naturally tend to go to bed a little later each night and wake a little later each morning. They find it extremely difficult to advance their schedule and go to bed earlier than they did the previous night.

Reduced sleep or difficulty sleeping is only considered a problem if it interferes with your life - if you wake feeling unrefreshed or find yourself dozing during the day. It is normal to sleep less as you age. If you're sleeping less than you did when you were younger, but don't feel tired during the day, you should not worry.

Typical daily sleep requirements by age:

The sleep of older people, as well as being shorter, is less deep. Only about 25% of the sleep of someone over 65 years is rapid eye movement (REM) sleep or stage IV (very deep) sleep, compared to over 50% in a young child. This probably means that older people dream less, since dreaming usually occurs during REM sleep.

As people get older, some get by with amazingly little sleep. Margaret Thatcher claimed to average two or three hours a night throughout her tenure as Prime Minister of Britain. Nevertheless, many people complain that a lack of sleep affects their daytime performance. At any given time, about 10% of the population consider themselves to have chronic insomnia. About half of us will suffer from insomnia at some point in our lives.