It is estimated that the average man or woman needs between seven-and-a-half and
eight hours’ sleep a night. Some can manage on a lot less. Baroness Thatcher, for
example, was reported to be able to get by on four hours’ sleep a night when she
was Prime Minister of Britain. Dr Jill Wilkinson, senior lecturer in psychology at Surrey
University and co-author of ‘Psychology in Counselling and Therapeutic Practice’,
states that healthy individuals sleeping less than five hours or even as little as two
hours in every 24 hours are rare, but represent a sizable minority.