When I was working and servicing MRI's, company policy was no more than 30 minutes per workday inside the bore of the magnet. Pivoting rapidly on my feet while standing near the magnet would sometimes make me dizzy. And the 3T's would try to grab my glasses. The 1.5T's were nicer. 😄
Most folks that have issues with MR's involve claustrophobia. I've seen seen some huge people fairly vault out of a magnet.