Human standing balance is affected by exposure to pulsed ELF magnetic fields: light intensity-dependent effects.

There is evidence in animals that behavioral and physiological responses to static and extremely low frequency magnetic fields (ELFMF) is affected by the presence of light during magnetic field exposures. Here we report that the effect of a specific pulsed ELFMF (PEMF) on human standing balance is modulated by light intensity during exposure. Under a low light condition (0.12 W/m2), nine healthy human volunteers stood on a 3D forceplate, throughout four 2 min exposures (eyes open/eyes close, sham/PEMF of 200 +/- 1 microTpk, order randomized). There was a significant increase in standing movement during PEMF exposure during eyes closed. In a second experiment on 26 normal subjects exposed to the identical protocol, but at greater light intensities (0.51 W/m2), a significant but opposite effect was observed.