[Madmallard]

not at all whatsoever. however if you have gadolinium injected for contrast some people have problems with that. but the magnetic field itself doesn't affect you negatively on its own

[ChainOfFools]

Is there a field strength at which the iron in your blood would start to become a problem?

[Madmallard]

This is probably an adequate answer to that:

https://www.reddit.com/r/AskPhysics/comments/3w03pj/comment/...