Love the side effects and symptom comparison!! So I am a flat lander. I was a PPA virgin last year. I felt like I was "drunk" once above tree line. I did NOT have a headache but was nauseous...not severely but just bothersome. I did take tums but did NOT eat enough early on. So I plan to do more tums and in general consume more calories earlier in the race. I take a LONG time to reach the peak!