Although being overweight is the common symptom, your tongue size doesn’t really change as far as I know, so if it’s large enough it may fall back and block your throat. If you ever wake up in a random panic, inhaling as if you’re gasping, you probably have sleep apnea.

There’s also central sleep apnea. This is less of a physical/weight thing, and more because your brain literally does not make the connections and order your body to continue breathing. I’ve experienced this a few times, especially when I’m sleep deprived. My body falls asleep within seconds, but I guess my brain is unable to comprehend it so I am still aware of everything but I just stop breathing. When using a CPAP machine, be aware that you may be aware and feel that you’re not breathing. I don’t believe it’s possible to pass out or die from simply not inhaling (read: no choking or obstruction, just simply holding your breath), so you’ll wake up. But, usually you ARE breathing but you just cannot feel it. In these cases, I would put my hand on my stomach so i can feel the automated inhalation and exhalation to calm myself down.