Medical experts estimate that more than 30 million American adults snore on a regular basis. Snoring or gasping sounds during sleep are caused by the vibration of relaxed, floppy tissues that line the upper airway (or throat). When you sleep, muscle tone decreases throughout your body, and your throat muscles relax, causing the soft palate and the uvula (fleshy structure that dangles from the roof of your mouth) to vibrate as you breathe in and out.