Sleep gives our bodies the opportunity to repair themselves and our minds a chance to rest. Without enough sleep, we feel irritable and inefficient, and we are less able to concentrate on our daily tasks.
Each individual needs a different amount of sleep, ranging from a brisk five hours to an indolent 12, although seven hours is about the average. The amount of sleep we need to revitalize and function efficiently during the day also changes as we grow older. Young babies sleep for up to 18 hours each day, but by the time we are elderly, this total has been cut to somewhere in the region of five or six hours. We also tend to wake more during the night as we age and take longer to get to sleep in the first place.
These are normal sleep patterns that alter as we progress through life. Insomniacs, on the other hand, have regular difficulty in falling asleep, wake frequently and are restless throughout the night, and often wake early only to feel tired during the day. The effects of a few broken nights are not serious but, for insomniacs, sleeplessness can last years. They frequently find themselves in the relentless, vicious circle of overtiredness and worrying so much about the need for sleep that they cannot relax.