It's mind over matter, you know that one, what works for me, might not work for you, but I had to learn to breath only thru my nose, also keeps your shield from fogging up, learned that in the hospital.
"Being old, isn't half as much fun, as getting there"! Ole Robert I!
Before I leave the house or when I get to the track, take dawn dishwashing soap and a paper towel and apply inside visor and on glasses. No water-just soap. Let it set for 10-15 minutes. Take soft toilet paper and wipe/buff all the soap off til clear- just like waxing a car. Should last the whole night.
I drilled small holes like Tim Bookmiller posted and I also used rain x anti fog wipes on the inside of the shield. When on real dusty tracks I did not like the holes in the shield so I used women’s roll on deodorant and applied it under my eyes and on my nose along with the anti fog wipes.
6565 Adam, the soap trick worked really well. I even tried breathing directly on them purposely, and although they fogged up just a little, it immediately went away. And Saturday was a hot muggy day at the track. Thanks for the tip!!