Definition
Apnea is suspension or cessation or a pause in breathing while you are sleeping. It usually occurs during sleep and is, therefore, called sleep apnea. Apnea is a Greek word, which literally means “without wind” or “without breath”.
It is a common sleep disorder and can have potentially serious consequences due to the deprivation of oxygen to the brain and body during the pauses in breathing.
Apnea need not be just a pause in breathing. Even abnormally low and shallow breathing can be classified as sleep apnea.
Usually, brief pauses in breathing are normal but when these pauses extend beyond 10 seconds during sleep, it is classified as sleep apnea. For a diagnosis of sleep apnea, more than five episodes per hour must occur.
In untreated chronic type, these cessations in breathing can last for 20 seconds or more and can occur several times an hour, sometimes as many as 30 times an hour, and hundreds of times during the night.
These gaps during which you do not breathe deprive the brain and body of oxygen causing disruption of sleep. It often completely awakens the person or may just bring the person out of his deep sleep into a more light sleep level.
This deprives him of the required sleep hours with the consequent drowsiness during the day. Such a person becomes a potential candidate for health complications of insomnia.
Sleep apnea is identified by its symptoms of which loud and chronic snoring (which is different from normal snoring) is the most common. To diagnose sleep apnea, your provider may have you do a sleep study. This will help him to identify the reasons that could be causing this condition.
This condition should not be ignored because of its serious complications and treatment should be promptly sought when diagnosed. As it occurs in sleep, a person having this rarely knows it, and it is often noticed by others around him.
Types
Sleep apnea is of three types:
1. Obstructive sleep apnea (OSA)
OSA is the most common type constituting about 84% of the cases. It occurs due to the relaxation of the soft tissue and muscles of the soft palate around the base of the tongue and the uvula situated at the back of the throat.
This leads to repetitive blockage of the upper airway, which causes breathing to pause during sleep.
This obstruction can be due to large tonsils or a large tongue, excess tissue in the airways, and also due to relaxation and contraction of the airway muscles.
At times, a particularly shaped jaw structure can also cause this type of obstruction in the airway. Loud snoring is typical with this type of sleep apnea because when you try to breathe, the air forcing its way through the blockage causes the snoring sound.
OSA is typically seen in middle-aged, overweight, or obese men, and women in later years. It is aggravated by the consumption of alcohol, sleeping pills, and tranquilizers taken at bedtime.
Symptoms include loud snoring, daytime drowsiness, failing memory, and irritability.
2. Central sleep apnea (CSA)
CSA is much less common (seen only in 0.4% of cases) and is due to central causes than due to any local obstruction.
In central sleep apnea, the brain fails to send signals to the respiratory muscles. These are the signals that tell the respiratory muscles to aid breathing. In the absence of these signals and without the contraction and relaxation of these breathing muscles, there is no muscular effort to breathe, causing the individual to miss one or more cycles of breathing.
This causes the individual to miss one or more breathing cycles. If the pause in breathing is long enough, the percentage of oxygen in the blood will drop low below normal (hypoxemia) and the concentration of carbon dioxide will increase to a higher than normal level (hypercapnia).
With constant hypoxemia alternating with hypercapnia for a long enough period, the brain cells are devoid of oxygen, which they need constantly. This can lead to permanent brain damage and even death can occur
Snoring is rarely seen in this type of breathing. Cheyne Stokes breathing can often mimic CSA.
3. Complex sleep apnea
The third type is a mixed type of apnea where both obstructive and central sleep apnea are present. This is particularly seen in infants and young children who have breathing problems.
Complex sleep apnea is a form of breathing in which repeated central apneas (more than 5/hour) persist when obstructive symptoms are removed with continuous positive airway pressure (CPAP) and for which a clear cause for the central apneas, such as narcotics or systolic heart failure, is not identified.
It can cause certain health complications due to sleep deprivation. These include high blood pressure, heart failure, stroke, and ischemic heart disease.
Untreated, sleep apnea can be life-threatening. Although there is no cure, effective treatment options are available including surgery for obstructive sleep apnea. Recent studies show that with successful treatment, the risk of heart disease, stroke, and high blood pressure can be reduced.
