What Causes Sleep Apnea?

OSA occurs in individuals whose upper airway is narrower or more collapsible than normal. The most common cause of this airway abnormality is obesity.

Having a large neck (men: greater than 16.5 inches around, women: greater than 15 inches around) increases your risk for OSA, because it narrows the airway. In small children, large tonsils are the most common cause of OSA. For some people with smaller jaws, OSA can also be more common. The drawing below shows the airway of a healthy individual (left) and an OSA patient (right). During sleep, the healthy patient is breathing normally without blockage, but the OSA patient's upper airway is obstructed, with the arrows showing the blockage. When your brain is given the choice between sleeping and breathing, it always picks breathing. So with obstructed breathing, your brain's response is to wake up. These awakenings are very brief and often are not remembered unless you wake up choking. Your throat muscles respond to your brain's message to wake up, you begin breathing again, your blood oxygen levels return to normal, and then you fall back asleep. If your airway partially closes and then you wake up, it is called a hypopnea. If your airway fully closes, it is called an apnea.

Summary of causes of Sleep Apnea

If you have obstructive sleep apnea, your airway can be blocked or narrowed during sleep because:

Your throat muscles and tongue relax more than normal.
Your tongue and tonsils (tissue masses in the back of your mouth) are large compared to the opening into your windpipe.
You are overweight. The extra soft fat tissue can thicken the wall of the windpipe. This causes the inside opening to narrow and makes it harder to keep open.
The shape of your head and neck (bony structure) may cause a smaller airway size in the mouth and throat area.
The aging process limits the ability of brain signals to keep your throat muscles stiff during sleep. This makes it more likely that the airway will narrow or collapse.

What are the Symptoms of Sleep Apnea

What Causes Sleep Apnea?

OSA occurs in individuals whose upper airway is narrower or more collapsible than normal. The most common cause of this airway abnormality is obesity.

Summary of causes of Sleep Apnea

Your throat muscles and tongue relax more than normal.

Your tongue and tonsils (tissue masses in the back of your mouth) are large compared to the opening into your windpipe.

You are overweight. The extra soft fat tissue can thicken the wall of the windpipe. This causes the inside opening to narrow and makes it harder to keep open.

The shape of your head and neck (bony structure) may cause a smaller airway size in the mouth and throat area.

The aging process limits the ability of brain signals to keep your throat muscles stiff during sleep. This makes it more likely that the airway will narrow or collapse.