LOndon, August 14: Some of the world’s greatest leaders, from Napoleon Bonaparte and Winston Churchill to Bill Clinton and Margaret Thatcher, are said to have managed on just four to six hours’ sleep a night, whereas the typical teenager finds it difficult to get out of bed in less than 10.
Newborn babies can sleep for up to 18 hours – admittedly at irregular intervals – whereas an elderly person may find it hard to sleep longer than six, although they often have to resort to the odd afternoon nap to make up for what they lacked at night.
Sleep is the quintessential ingredient of life. Every animal does it at some point in the 24-hour cycle and people who are forcibly deprived of sleep are effectively undergoing torture. But the big unanswered question is how much sleep do we actually need?
Seven ages of sleep
1 Sleep in newborn babies occurs around the clock on an irregular cycle
2 Babies between three and 11 months usually begin sleeping through the night
3 Toddlers between one and three years old need between 12 and 14 hours of sleep and daytime naps
4 Pre-school children begin to have nightime fears and nightmares
5 Problems in the five-to-12 group linked with television and computers
6 Adolescence associated with long sleeping patterns thought to be necessary for development
7 Adult sleep can become progressively difficult and disturbed
–Agencies