Breathing often seems like the easiest thing in the world. Most of the time, you don't even think about it. But if you've ever had a stuffed-up nose, you know the feeling of trying to breathe through a very narrow passageway. This is what happens in your throat when you snore. While you sleep, structures in your throat partially block your air passage, making the passage narrow and hard to breathe through. If the entire passage becomes blocked and you can't breathe at all, you have sleep apnea.
When you breathe in, air passes through your throat on its way to your lungs. The air travels past soft, flexible structures in the throat such as the soft palate, uvula, tonsils, and tongue. During the day, muscles surrounding each structure tighten to hold the structure in place so it doesn't block the air passage. During sleep, these muscles relax, but the passage in your throat still stays clear enough for air to flow freely into and out of your lungs.
If your throat structures are too large or the muscles relax too much during sleep, the air passage may be partially blocked. As air from the nose or mouth passes around this blockage, the throat structures vibrate and rattle against each other, causing the familiar sound of snoring. At times, this sound can be so loud that snorers wake up others, or even themselves, during the night. Snoring gets worse as more and more of the air passage is blocked.
If the structures completely block the throat, air can't flow to the lungs at all. This is called apnea. Since the lungs aren't getting fresh air, the brain tells the body to wake up just enough to tighten the muscles and unblock the air passage. With a loud gasp, breathing begins again. This process may be repeated over and over again throughout the night, making your sleep fragmented and light. Even though you don't remember waking up so many times during the night, your feel tired all day. The lack of sleep and fresh air can also strain your lungs, heart, and other organs leading to problems such as high blood pressure, heart attack, or stroke.