But your sleep may not be as disturbed as you think. It may be the timing of your sleep that is off. The clash between desired and actual sleep time , he says, is a key feature of several distinct sleep disorders that affect about one in ten chronic insomniacs.
Normal timing is part and parcel of our perception of normal sleep.
But then they wake up in the middle of the night and can't fall asleep again. Jet travelers often have trouble sleeping for a few days in a new time zone. Shift workers, who frequently change the hours they work and sleep, Dr. Richardson says, face the same problem as travelers, without leaving home. People who are ill, particularly if confined to bed, often lose track of time and doze off and on around the clock.