That's an interesting question you pose. I asked that same question myself before going to Disney a few weeks ago with family. I figured that if I could stay 'calm' and enjoy the ride I would go on it. My husband LOVES rides! We ended up going to Epcot and I did agree to go on Speed Track and 'lived to tell the tale'. I do recall that there was a warning stating that anyone with certain health conditions ie. heart condition etc. should not go on this ride. Obviously, common sense was not dictating my decision at that moment.
Here's a description of the ride: The highlight of the ride is a speed trial on a track around the outside of the Test Track building at a top speed of 64.8 miles per hour (104.3 km/h) on a 50-degree banked curve, making Test Track the fastest Disney theme park attraction ever built, next to California Screamin', Rock 'n' Roller Coaster, and Tokyo DisneySea's Journey to the Center of the Earth (which uses an improved version of Test Track's ride system).