Magnetic and electric fields
A human body moving through magnetic fields experiences biological effects. Some people react to geomagnetic storms or geomagnetic changes in geological fault lines.
Faraday’s law of induction of 1831 explains how a change in a magnetic field induces an electric current in a suitable medium, like the human body and brain. Thus moving through geomagnetic variations induces electric currents affecting muscles in a dowser, and Transcranial Magnetic Stimulation, using a magnetic field of similar strength to Magnetic Resonance Imaging (MRI), induces small electric currents in the brain. In a similar way a sensitive person moving through static MRI magnetic fields induces bodily electric currents, vertigo and other common electro-sensitivity symptoms.
Animals navigating through the Earth’s magnetic field induce electric currents of half a billionth of a volt.
Magnetic Resonance Imaging scanners produce large magnetic fields. People moving through these fields experience a variety of typical electro-magnetic sensitivity fields.
The largest observational study so far, of 331 employees at 14 MRI facilities, found a positive association in a small sub-group between working with MRI ≥1.5 Tesla and transient acute symptoms, such as vertigo (6% of shifts), metallic taste (2%), nausea (1%), magnetophosphenes, balance problems and tinnitus, with no symptoms when the staff were not working with MRI. Symptoms lasted up to 15 mins and tended to occur more frequently with stronger scanners, from 1.5 to 7T; Odds Ratios ranged from 1.9 for 1.5T, to 4.2 for 7T for target symptoms, and from 2.4 for 1.5T, to 66.8 for 7T for core symptoms. 10% of the 103 participants who reported symptoms said that their work had been affected, especially in concentration, pace or efficiency. The symptoms were reported by a cluster or sub-group, suggesting “personal sensitivity”, with perhaps higher sensitivity in the vestibular system. The design of the study did not prevent the staff who knew they were sensitive from walking more slowly through the static magnetic fields, or even avoiding work with MRI scanners altogether. (Schaap K et al, Occup Environ Med., 2014, article).
'Windows' or particular bioactive frequencies or signal patterns
It has long been known that electromagnetic exposure does not cause a linear response in all living tissue. In many cases there are exposure is bioactive at one frequency, but not at another, depending on a range of factors. This makes testing biological effects of radiation problematic, since most studies have failed to look for this phenomenon and some invalidly conclude 'no effect' when they would show an effect at a slightly lower or high frequency or signal pattern. Most heating limits, such as those still promulgated by ICNIRP, are therefore invalid. Markers of DNA damage are much more reliable than a false extrapolation based on the invalid linear model.
In 1998 ICNIRP recognised the fundamental problem of frequency 'windows'. This undermines all its attempts at setting limits based on heating effects only.