Sleep apnea is when someone temporarily stops breathing while sleeping. The physiological effects of this cessation in airflow can create a host of negative effects. The side effects of sleep apnea include sleepiness or fatigue, hypertension and other cardiovascular issues, increased risks of metabolic syndrome and type II diabetes, as well as possible issues with sleep partners.1 Understanding sleep apnea causes is important if you or a loved one suffer from sleep apnea.
There are two types of sleep apnea, central sleep apnea and obstructive sleep apnea. Central sleep apnea is when someone stops breathing while sleeping because there is an issue with the signal to breathe. A healthy central nervous system automatically sends signals to breathe as needed. This is why we don’t need to consciously control our breathing.
Central sleep apnea can involve a problem with the generation of this signal, or with the actual conveyance of the signal. Central sleep apnea causes that can cause the breathing signal to not be generated include trauma to the areas that create the signals, acute opioid usage, and complications from obesity.
Central sleep apnea can also happen when the signal to breathe is unable to travel from the brain to the diaphragm, the primary muscle involved in breathing. Damage to the phrenic nerve, which exits the spinal cord in the middle of the neck before travelling to the chest, can result in the inability to breathe. There can also be issues with the junction between the nerves that carry the signal and the muscles that are meant to respond to the signal.2
Obstructive sleep apnea is when there is a physical obstruction in the airways which completely blocks breathing. The mouth and throat are lined with soft tissues, which are normally prevented from blocking breathing by simple muscle tension. When someone completely relaxes during sleep, these soft tissues can sag into the airways. A partial obstruction can result in snoring, and a complete obstruction is sleep apnea.
Whether the soft tissues in the throat and mouth block the airways can be caused or influenced by a number of different risk factors. Being overweight or obese is highly correlated with obstructive sleep apnea. In fact, having a higher body mass index is more than double the risk factor than any other sleep apnea cause.
There are also congenital factors that increase the risk of obstructive sleep apnea. Men are more likely than women to experience severe sleep apnea. There are also physiological differences, such as a deviated septum, that can increase the risk of sleep apnea.
Nearer-term causes include the use of drugs like alcohol or opiates. Alcohol causes the muscles in the throat to relax. Opiates cause respiratory depression, meaning less pressure is produced by breathing. Both of these are sleep apnea causes.3
While there is evidence that anxiety disorders occur with greater prevalence among sleep apnea sufferers,4 stress is not considered to be a sleep apnea risk factor. Stress is considered to be a cause of other sleep disorders such as bruxism, or teeth grinding, and insomnia, or trouble sleeping.
Being overweight is a significant contributor to a host of sleeping issues, including snoring and obstructive sleep apnea. In fact, being overweight is the highest contributing sleep apnea risk factor.5 What is more, sleep apnea has been found to increase weight gain6 , which in turn increases the risk of sleep apnea. Losing weight has been found to reduce the incidence of sleep apnea.7
Sleeping position can affect the likelihood of obstructive sleep apnea. The worst sleeping position for sleep apnea is supine, or lying flat on your back. Research that has tested different sleeping positions has found that sleeping laterally, or on your side, reduces obstructive sleep apnea.8 Another position that reduces obstructive sleep apnea relative to a supine sleeping position is at an incline. A pile of pillows or specially designed support that elevates the torso, head, and neck has been found to reduce the severity and incidence of obstructive sleep apnea.9
© 2021 American Sleep Association.