If you have trouble sleeping, you may be accumulating a debt that is difficult to pay back - a sleep debt. According to the National Sleep Foundation, about 6 out of 10 people in the United States suffers from problems getting a restful night of sleep.
There are many kinds of sleep disorders, including:
Insomnia. Poor quality sleep may result from inability to fall asleep, waking up frequently, waking up and being unable to return to sleep, or some combination. Females are affected more than males.
Lifestyle-related. A hectic and stressful lifestyle, work demands and over-active social lives can lead to accumulation of sleep debt. Even the use of an alarm clock can trigger more and more debt.
Sleep apnea.