GERD, laryngopharyngeal reflux disease and sleep apnea are all related. When you wake up gasping, you just had an obstruction, which causes a vacuum effect that literally suctions up your normal stomach juices into your throat. That's what wakes you up. Stomach juices in your throat lead to laryngopharyngeal reflux disease, which will give you the following: difficulty swallowing, dry mouth, cough, lump sensation, pain, post-nasal drip, or throat clearing. You can have one or all of the above. You also have to realize that it's not just acid coming up—there's also bile, digestive enzymes, and bacteria. If you stop breathing for 10 seconds or longer, that's called an apnea. If you stop breathing for 1-9 seconds and wake up, then it won't be counted as an apnea on a sleep study, but you'll still suction up your normal stomach juices.
Taking acid reflux meds is a start, but make sure you're taking it twice daily, before breakfast and dinner. Just realize that acid reflux medications don't do anything to prevent reflux—it just lowers the acid content in your stomach. This is why this regimen helps some people, but not everyone.
Sometimes, even slight nasal congestion can aggravate throat/tongue collapse in people with sleep-breathing problems. One quick test to see if you sleep better is to use a combination of Afrin and Breathe-Rite Strips for 2-3 nights only. If you sleep much better, then it's probably worth considering a nasal procedure to help improve your breathing. However, doing definitive nasal surgery "cures" sleep apnea in only 10% of people.
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