But she works with strong magnets - could this be a factor?

I'm not aware of any effects of magnets on blood flow, but they can be used to measure blood flow, in a technique called MRI - Magnetic Resonance Imaging. This works by putting someone in a very strong strong magnet, and under those magnetic conditions all the water molecules in the body line up in a straight line. The scanner then sends a pulse of radio waves which disrupts some the water molecules, some of the hydrogen actually, and they flip into a different orientation, and then flip back, producing a signal which enables you to measure what the tissue looks like in an Magnetic Resonance Scan. You can also do this to measure blood flow using a process referred to as MRA or Magnetic Resonance Angiography.