Dry sinuses during sweet spot

I was about halfway through Eclipse today (90min sweet spot, but there is nothing sweet about 20 min intervals) and my sinuses got very dry, kinda like when I’m starting to come down with a cold. I have heard so much about depleted carbs I wondered if this could have been caused by that or if simply I’m starting to get sick. Any thoughts?

Could be nothing. Lots of breathing through your nose? Fans pointed at your face drying you out? Coming into winter and lower humidity?

Good point, I did install a new fan in the paincsnve today and took the sweat catcher off my bike helping with the airflow, hopefully that is it!