Now that i am older and ride roller coasters with my kids i feel nauseous and have veritgo. why does this happen when i used to do it fine?

Roller Coasters: Are unnatural...Let me be upfront here...I do not like them. They are dangerous. When you were younger they were not as fast or steep or jerky. Roller coasters can precipitate stroke in some people. As we age (yuck) our necks and vessels are more prone to injury from all that jerking and the force of the coaster is making you nauseated, etc.