You cannot attend this course if you have certain healt conditions. You cannot have a pacemaker. You cannot have implanted other Medical Devices in your body. If you have been in a war zone either as a civilian or as a soldier and you have been in actual battle and got iron shrapnel from grenades or similar in you body and these parts are not completely removed you cannot attend. The iron pieces might start moving in the magnetic fields and harm you seriously or kill you.
If you are pregnant or plan to become pregnant during the course you should not get close to the magnets, but let another person add and remove samples for you. There is no evidence of harming an unborn child by the magnetic fields - but it is better to be safe than sorry.