Thank you for your reply, Pete. I will ask the cardiologist why he wants to perform this test. I had just eaten, so I don't think it was due to blood sugar. I had my electrolytes, glucose, insulin, and blood counts tested, so I will hopefully find out those levels soon. My pulse dropped to 32 during the spell. After the spell they checked my bp more than a dozen times and recorded it-my bp dropped when I sat up or stood up. I became dizzy and weak upon standing. The ekg showed skipped beats...and later too many beats. If the 24hr heart monitor is normal, they will perform the TTT. I am also being evaluated for frequent seizures and narcolepsy. They don't know what causes my spells-I am pretty sure it is my cortisol bottoming out. I do lie down, but it has never really prevented a spell, I wish it would! I am so exhausted that I will fall asleep no matter what I am doing (I was driving this time-I pulled over at a gas station and fell asleep at the pump!-my car was still running. Someone knocked on my window, so I pulled into a parking space and slept.) Now I am not allowed to drive!!!! Thank you for sharing your experience. I will definitely ask the cardiologist about it. Take care. Meri | 