Study type: Medical/biological study (experimental study)

Effects of 50 Hz electromagnetic fields on electroencephalographic alpha activity, dental pain threshold and cardiovascular parameters in humans. med./bio.

Published in: Neurosci Lett 2005; 382 (1-2): 112-117

Aim of study (acc. to author)

The effects of exposure of subjects to a 50 Hz magnetic field on brain activity, nociception and cardiovascular parameters should be investigated.

Background/further details

Some studies suggest effects of 50 Hz magnetic field exposure on brain activity and nociception, which should be verified. Since cardiovascular regulation is functionally related to pain modulation, some relevant cardiovascular parameters were measured additionally.
40 healthy male subjects participated in the study. Subjects were randomly assigned to one of the two exposure intensity groups (n=20 each; however, only data from 10 subjects from group 1 and 15 subjects from group 2 were analyzed): 1) 40 µT magnetic field and 2) 80 µT magnetic field. Each volunteer was investigated during two sessions at an interval of 1-2 weeks: one exposure session and one sham exposure session. Exposure and sham exposure were conducted in a random order (cross-over study).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 90 min
Exposure 2: 50 Hz
Exposure duration: continuous for 90 min

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 90 min
Exposure setup
Exposure source
Chamber subject was comfortably seated in a quiet room
Setup 2 circular coils, similar to Helmholtz coils (44 cm in diameter, each composed of an aluminum ring on which 50 copper coils [0.8 mm diameter] were winded), produced the magnetic field; the coils were positioned around the head of the subject with the head at the center of the coils; the subject was invited to read a magazine during exposure
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 40 µT peak value measured - -

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 90 min
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 80 µT peak value measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • before exposure
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

Brain activity in the alpha wave band was significantly increased after exposure to the 80 µT magnetic field (group 2) compared to the sham exposure.
The pain threshold was significantly lower after exposure to the 40 µT magnetic field (group 1) compared to the sham exposure.
No differences were found in blood pressure, heart rate and hormonal blood levels between exposure and sham exposure in both groups.
The authors conclude, that exposure of subjects to a 50 Hz magnetic field might affect the alpha wave brain activity and nociception, though it is uncertain whether both effects are linked.

Study character:

Study funded by

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