Simply ... you know how you brain freeze works when you eat ice cream? You eat it then.. wait..wait... bam.. brain freeze ...ouch I can see why someone would get dizzy if they locked their knees or even played a very long passage on a single breath and end on a "high" note but when you are playing a range exercise? It's an arpeggio on a lung full of air. I go 4th space E up in the arpeggio... hit the high E ... wait waait... then bam dizzy. Not playing very loud either ... I was just wondering what causes that... or what can cause that. Is there a doctor in the house?