I live at 6,000 ft. Went to 9,000 Fri night. next morning I drove to Arapahoe Basin. It was the first ski run of the day. I reached 12,000, Skied slowly for a couple hundred yards and started getting severe tremors. Had to be taken off the mountain in a tobogan. Usually when I ski at altitude I only get light headed (not dizzy) and a little nauseous. Could these severe tremors (The MD didn t see anything in a chest xray , BP was high for me but not of concern to the Doc and O2 levels OK, 12-lead EKG normal). I am not sure which blood tests were run but they all came backk OK. Urine for infection came back negative.Could the severe tremors be caused by the altitude somehow?