In this Article

• What is problem sleepiness?
• What are the symptoms of problem sleepiness?
• What causes problem sleepiness?
• Sleep-wake cycle
• Inadequate sleep
• Sleep disorders
• Medical conditions/drugs
• Problem sleepiness and adolescents
• Shift work and problem sleepiness
• What can help for problem sleepiness?
• Problem Sleepiness Glossary
• Problem Sleepiness Index

Inadequate sleep

The amount of sleep needed each night varies among people. Each person needs a particular amount of sleep in order to be fully alert throughout the day. Research has shown that when healthy adults are allowed to sleep unrestricted, the average time slept is 8 to 8.5 hours. Some people need more than that to avoid problem sleepiness; others need less.

If a person does not get enough sleep, even on one night, a "sleep debt" begins to build and increases until enough sleep is obtained. Problem sleepiness occurs as the debt accumulates. Many people do not get enough sleep during the work week and then sleep longer on the weekends or days off to reduce their sleep debt. If too much sleep has been lost, sleeping in on the weekend may not completely reverse the effects of not getting enough sleep during the week.

Sleep disorders

Sleep disorders such as sleep apnea, narcolepsy, restless legs syndrome, and insomnia can cause problem sleepiness. Sleep apnea is a serious disorder in which a person's breathing is interrupted during sleep, causing the individual to awaken many times during the night and experience problem sleepiness during the day. People with narcolepsy have excessive sleepiness during the day, even after sleeping enough at night. They may fall asleep at inappropriate times and places. Restless legs syndrome (RLS) causes a person to experience unpleasant sensations in the legs, often described as creeping, crawling, pulling, or painful. These sensations frequently occur in the evening, making it difficult for people with RLS to fall asleep, leading to problem sleepiness during the day. Insomnia is the perception of poor-quality sleep due to difficulty falling asleep, waking up during the night with difficulty returning to sleep, waking up too early in the morning, or unrefreshing sleep. Any of these sleep disorders can cause problem sleepiness.