What's clogging my ears/earbuds when running? Sweat/earwax? How to fix?

I would suspect sweat first. My LG HBS730 can have that same problem. Even worse, if sweat gets in the ear bud, there's a "grill" in front of the speaker which spreads the sweat out. End result is once that gets wet, volume is cut down to 20% of normal volume until it fully dries out (I.E. tomorrow). They only way that I can prevent this is to use the right size of the ear plugs, and be sure that they're firmly in to seal the sweat out. I'm definitely in the heavy sweater category. Most ear buds come with 3 sizes, try going up a size to make the fit more snug. It could also be ear wax; you should be able to look in the ear bud and see if you can see ear wax. If so dried ear wax might move around in the bud blocking sound randomly. Plus, ewww :) , so get that cleaned out. Due to the size of ear buds, tooth picks are what I've found works best.

Are you sure it's your ear and not the headphones? It sounds like your left earbud may be crapping out after a certain amount of jostling, and the act of taking it out and putting it back in jiggles the wire in such a way that it starts working again. (I use earbuds at work, often without any noise coming through them, just to muffle sound - that could be the "plugged" feeling you're experiencing.)

Mine will plug with sweat, for sure. I'm looking to upgrade to bone conduction headphones, which have their own issues but can't clog.

Your ear sweat is creating suction, which is creating the clogged feeling. Taking the earbud out breaks the seal.

This is almost certainly due to sweat. I encountered this problem a lot until I upgraded to http://www.amazon.com/exec/obidos/ASIN/B00HZ5Z4GI/metafilter-20/ref=nosim/ that I found on this list of http://thewirecutter.com/reviews/best-exercise-headphones/.

Are you sure it's your ear and not the headphones? FWIW, I have the exact same issue when wearing earbuds for long periods of time and have experienced it with several different pairs so I don't think it's a technical problem with your earbuds, OP.

Hi, am an audiologist, not yours, blah blah. Pressure in the ear canal would not really noticeably change how you hear. You might be getting a slight pressure seal from a combo of the wax and sweat, which may give you that plugged feeling. But as far as not hearing the music, that's almost certainly because of sweat and wax in the earbud receiver - and really, in your ear, sweat and wax sort of become the same kind of thing, moisture secretions from glands in your canal. The moisture can either block the actual receiver of the earphone or wet it enough that it shorts and doesn't come back online until it dries completely. Fwiw, this is a super common problem with hearing aids. What you might want to try is an earphone that has a bit better barrier between your ear juice and the receiver. With an apple ear bud type earphone, the mesh is right there on the surface, and it's easy to get moisture down there. You might want to try something with a rubber tip that extends out and around the receiver cover, so less moisture can make its way down there. Better yet, look for something with tips that can come off, so you can remove the tips after the run and let everything dry off. Even better might be considering deeper insertion phones, so you won't get all the sweat from your head and hair dripping onto the receiver port of the earphone (something like an Etymotic HF or ER earphone). You could consider a bone knocker headphone too, which would eliminate the problem altogether. You'll suffer sound quality a bit, and not everyone likes the sensation of it.

I've had great luck with http://www.amazon.com/exec/obidos/ASIN/B00M5A7FJW/metafilter-20/ref=nosim/ style of gelly thing that sits more on your ear than in it style "earbud". Wore them every time i went to the gym until i lost them. This exact problem you're describing has happened to me, but it never happened with those.