The most common sleep disorder to cause excessive daytime sleepiness is obstructive sleep apnea (also simply called sleep apnea). During normal sleep, everyone’s muscles relax, including the tongue and throat muscles. In people who have obstructive sleep apnea, the airway structure is so narrow behind the tongue or soft palate (the structure that hangs down in the back of your throat) that it closes (obstructs) when the muscles relax. This causes “apnea,” which is Latin for “no air.”
During an apnea, the lungs receive no fresh air, so blood oxygen falls to very low levels. The muscles of the chest and abdomen work harder, trying to overcome the obstruction to airflow. These abnormal conditions cause the brain to wake up, usually so briefly that the person does not remember having been awake. As soon as the brain wakes up, the muscles tense up, the tongue moves forward, the airway opens and the oxygen level rises. The brain promptly goes back to sleep and the cycle starts over.
If obstructive sleep apneas occur frequently enough, they are so disruptive to the normal sleep pattern that sleep is not refreshing. People with significant obstructive sleep apnea are literally sleep deprived. They remain sleepy during the day, even when spending normal or increased hours sleeping.
Obstructive sleep apnea is commonly, but not always, accompanied by snoring, gasping breaths during sleep, or pauses in breathing witnessed by a bed partner. It is most common in those who are overweight, but occurs in people with normal body weight as well.
Obstructive sleep apnea is a surprisingly common medical condition. Studies have reported that apnea or hypopnea (partial obstruction of the airway with similar effects on sleep) occurs in 9% to 25% of adult men and 4% to 15% of adult women. Sleep apnea is most common in middle age. Sleep apnea may be present in up to 3.5% of children.
If the sleepiness is severe enough, the person may fall asleep when driving or operating other equipment, resulting in injury or even death. Even if these accidents are avoided, frequently repeated obstructive sleep apneas may lead to high blood pressure, congestive heart failure, memory problems, emotional or personality changes, and even strokes.
If you have excessive daytime sleepiness and symptoms of sleep apnea, you should obtain an evaluation to decrease your risk of accidents and medical complications of sleep apnea.