Okay guys, im new to this forum, and i tried to find this topic being discussed using the search feature, but i couldnt find much. Please forgive me, and help me with this problem. Anyways, I recently began (well finished) my first semester of Graduate school after taking two years off from teaching High School. I never had this problem before, but, now When playing long phrases in the extreme upper register, i get really lightheaded. It really scared me because during our spring concert (I play lead in the big band), i nailed this lick, but at the end of it, i had to rest the next few bars or else i would've PASSED OUT! I know i have a tendency to take in lots of air, but i guess i dont use all of it and i perform a the "sleeper hold" on myself. I would appreciate any assistance anyone could give me regarding this issue, and how i could fix it. Id hate to fall off the risers during a performance! lol!