One of the most common reasons people struggle with obtaining a good night’s sleep is because of a common sleep disorder called Obstructive Sleep Apnea (OSA).
OSA occurs when the base of the tongue and the uvula relax and sag, causing the airway to collapse and sometimes close completely. While the airway is obstructed, loud snoring is present. However, when the snoring stops or pauses, the sleeper has stopped breathing entirely. The lack of oxygen causes him to wake and gasp for breath. This cycle (known as the Obstructive Sleep Apnea Cycle--see diagram above) may be repeated hundreds of times per night!
Obstructive Sleep Apnea (OSA) occurs when air is blocked from entering the lungs during sleep. For air to get to the lungs it must first go through the “upper airway” (airway). The airway includes the nose, mouth and parts of the mouth behind the tongue that cannot be seen without special instruments.
The airway is similar to a tube, and some parts have the tendency to collapse (see illustrated cross-section above). The area behind the tongue in the diagram shows a common site of collapse. When it occurs behind the tongue air cannot get from the nose or mouth into the lungs. To prevent collapse, there are muscles in the airway that keep the airway open.
During the day these muscles work completely. However, when a person sleeps, these muscles relax. Normally the airway stays open even when the airway relaxes. In people with OSA, the airway collapses or is close to collapsing when the airway muscles relax.
What Causes OSA?
The Role of Weight
Putting on weight increases the tendency for the airway to collapse. The reasons are not completely known. Fat can accumulate in the tissues surrounding the airway, just as fat accumulates in other parts of the body. The accumulation of fat can change the shape of the airway rendering it more likely to collapse. Thus, it is not surprising that some studies have found that persons with a large neck are at higher risk for sleep apnea. Typically men with a neck size of approximately 17 inches or higher and woman with a neck size of approximately 16 or higher may be a risk for OSA.
Certain jaw or facial structures or attributes, such as a recessed chin may cause OSA. The shape of the jaw is important. When the jaw is small, the tongue sits further back in the mouth. This increases the tendency for the tongue to pinch off airflow during sleep.
Alcohol and Medications
Alcohol and some medications relax airway muscles. Drinking alcohol can worsen or tip someone into obstructive sleep apnea.
Extra tissue in the back of the throat, such as large tonsils or uvula can partially block the airways. This condition is more prevalent in children.
When lying on your back, gravity pulls the tongue toward the back of the mouth. This, too, increases the tendency for the tongue to pinch off airflow during sleep. Some people have obstructive sleep apnea or have more severe sleep apnea on their back.
Smoking irritates the tissues of the upper airway, and can cause them to swell. Swollen tissues increase the chances of physically narrowing the airway.
Sleep Apnea Statistics
- Sleep apnea affects over 18 million Americans
- All chronic sleep disorders combined affect over 40 million Americans
- Sleep apnea is as common as diabetes or asthma
- >10% of people with sleep apnea have been diagnosed
- Poor sleep is a leading cause of depression
- 80% of drug resistant hypertensive patients have sleep apnea
- 73% of type II diabetics
- 50% of congestive heart failure patients
- 40% of all hypertensive patients
- 30% of coronary artery disease patients
Untreated Sleep Apnea
What if OSA is not treated?
People who do not seek effective treatment for OSA can be at increased risk for high blood pressure, heart disease, heart attack, stroke, fatigue-related motor vehicle and work accidents, and a decrease in their quality of life. Other side effects may include excessive daytime sleepiness or fatigue, memory problems, weight gain and headaches.
How Does OSA Affect Blood Pressure?
OSA causes a person’s upper airway to collapse during sleep. The brain realizes that it is not getting enough oxygen and wakes the person from a deep sleep level to a lighter level of sleep. Each time this happens, the body produces chemicals or hormones that increase the heart rate and blood pressure. When the OSA sufferer relaxes and goes back to a deep level of sleep, the heart rate drops back down to resting levels. This can happen hundreds of times while the person is asleep. Each time the heart rate increases or decreases, blood pressure is affected.
The elevation in blood pressure can last a few minutes or as the severity of apnea increases, it can last all night. Nighttime fluctuations in blood pressure make it harder to control and maintain a healthy blood pressure. Over time, the repetitive increases in nighttime blood pressure lead to increased daytime blood pressure.