Abstract
Advances in science and technology over the last century have resulted in a steady increase in the average life expectancy of human beings, especially in developed countries. This trend implies a gradual increase in the proportion of older adults in the general population and that this group of the population will account for an increasing and significant proportion of patients seen by physicians in most clinical disciplines in the near future. For this reason, understanding the aging process and associated changes that occur in the different organs and systems is of paramount importance. Accordingly, age-related changes occur in sleep and wake system and these are described below.