Try to keep your mouth as close to closed as you can! I found that after about 3 laps on any of the tracks around me, your throat will be coated with dust and breathing will become more and more difficult, breathing through your nose is tough to do for me, so I keep my mouth open like im drinkin thru a straw and that works. Sticking foam from an air filter or something in your mouth guard might work, whoa thats such an awesome idea.