# Effects of a very large magnetic field on the human body

Ever since reading about the NHMFL I have always wondered about this and asked several people without getting a good satisfactory answer. My question is, considering the simplest case let's say a uniform magnetic field with a very high magnitude constant both in time and space permeating a large room, what would happen to my body in such a field like if I was to just walk through it? How large would the magnitude need to be before I "feel" anything? One tesla is fairly large, would I feel anything? I imagine as we crank up the magnitude, I would feel queasy and sick. What if I crank it up to fifty teslas or a hundred teslas? Would it hurt? Would it mess up my synaptic potentials? Would I go crazy with a dysfunctional brain? Would I pass out or go into a coma? At what point will the damage become irreversible? What magnitude will cause death? With a high enough magnitude would molecules in my body start falling apart? What happens at hundreds of teslas? Thousands of teslas or millions of teslas?

The closest thing here I found was here in the accepted answer "a magnetar that would be 1000 miles away would kill us due to diamagnetism of water in our cells". This is the kind of stuff I am looking for, the magnitude of the B-field and then its effect on a human body. Like "at 100T, your body would __ because _ and at 1000T, your body would _____ because ____" and so on.

If we allow changes in the magnetic field in time, does the induced electric field "hasten" the effects somehow? Would a strong enough E-field cause a shock within us burning our organs and killing us even if the average B-field is small but the db/dt is "large" for example?

I don't know if any experiments on biological samples have been done because artificially creating magnetic fields beyond a 100T or so hasn't been quite done yet much less sustaining them and observing the effects on a biological tissue. But if there are any cool references even if they are on theoretical grounds, that would be interesting.

Thanks.

Edit: Just to make the question more answerable, I'll focus only on static fields. Anyone know of any references/experiments regarding the effects of large magnetic fields on biological tissues?

-
Duplicate: physics.stackexchange.com/q/15747/4552 – Ben Crowell May 9 '13 at 11:40
This seems to me to be a bit broader than that question. – Emilio Pisanty May 12 '13 at 20:55

## 2 Answers

I'm only going to try to address the question of DC fields.

Medical MRI uses uniform fields of about 0.5 to 3.0 T. In a head MRI, the Lorentz force on ions in the brain can cause neurological effects such as vertigo. I've heard that this shows up in particular when the patient moves his head.

Here is a famous picture of a frog being levitated by a 16 T magnetic field. This effect requires a nonuniform field; a diamagnetic object is attracted to a region of lower field strength. I've always assumed the frog was unharmed, but I don't know for sure.

Based on this, it sounds like the result depends on whether the field is uniform or nonuniform.

-

One simple approximation that you could make is to assume that the human body is made of water. Then you can reduce your question to: what happens to water molecules in a magnetic field. Consequently, you would have to ask how you can break the Van der Waals Bond in water with a magnetic field.

I think here you would have to differentiate between a static or dynamic magnetic field. For instance, a 10 T static magnetic field can levitate water molecules, but is it enough to rip them apart?

If you apply some sort of dynamic EM-field, for instance in the microwave range, you can heat up the molecules, which is the working principle of the microwave oven.

-
I'm not a chemist but how is a Van der Waals Bond related to a water molecule? The bond between $H$ and $O$ is polar covalent and the bond between $H_2O$ molecules is a $H$-bond. All of them should be harder to break than a simple dipole-dipole (van der Waals) interaction. – Mike Apr 21 '13 at 1:01
@Matthias I didn't phrase the answer correctly. Now I replaced a molecule by molecules. Water can be described by Van der Waals Bonding. I also updated the corresponding link in the answer. – seb Apr 21 '13 at 5:33
The previous answer cited the effects of magnetism on water. However, it must be considered that there exists a potential physiological effect due to the magnetic properties of iron, found primarily in hemoglobin, but also known to accumulate in sinus bones. I do apologize for not adding this in the comment section, but I am new to this forum and was unable. – user29417 Sep 9 '13 at 21:09

## protected by Qmechanic♦Sep 9 '13 at 21:16

Thank you for your interest in this question. Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site.

Would you like to answer one of these unanswered questions instead?