Study type: Medical/biological study (experimental study)

Exposure to strong ELF magnetic fields does not alter cardiac autonomic control mechanisms. med./bio.

Published in: Bioelectromagnetics 2000; 21 (6): 413-421

Aim of study (acc. to author)

The effects of exposure of subjects to a 50 Hz magnetic field on the heart rate variability should be investigated.

Background/further details

Sastre et al. 1998 found significant alterations in the heart rate variability of men by intermittent exposure to an magnetic field. These results should be verified and specified.
24 healthy young men (though only data of 18 were analyzed) participated in 3 over-night sessions, respectively. Each session was randomly dedicated to either 1) continuous exposure, 2) intermittent exposure or 3) sham exposure and each subject served as its own control. During intermittent exposure, it was analyzed if the precise timing of when the magnetic field switched on or off resulted in phase-resetting of the cardiac rhythm.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 60 Hz
Exposure duration: continuous for 8 hours (from 23.00 pm to 7.00 am)
Exposure 2: 60 Hz
Exposure duration: intermittent (1 h on - 1 h off) for 8 h (from 23:00 pm to 7:00 am)

Exposure 1

Main characteristics
Frequency 60 Hz
Type
Polarization
  • circular
Exposure duration continuous for 8 hours (from 23.00 pm to 7.00 am)
Exposure setup
Exposure source
Chamber test room (a cube of about 2.4 m side length)
Setup two Merritt coil systems placed behind the ceiling, walls and floor of the test room; the test person slept on a bed in the room with his body oriented north-south; the horizontal axis of the uniform field (about 2.5% deviation) was oriented north-south and the vertical axis was perpendicular to the floor
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 127.3 µT - - - -

Exposure 2

Main characteristics
Frequency 60 Hz
Type
Polarization
  • circular
Exposure duration intermittent (1 h on - 1 h off) for 8 h (from 23:00 pm to 7:00 am)
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 127.3 µT - - - -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

There were no effects of continuous or intermittent exposure to 50 Hz magnetic field on the heart rate variability found in subjects.
The authors conclude that further research is needed to resolve the differences between the present and the earlier laboratory based studies and to determine if cardiac rhythm disturbances are associated with exposure to the more complex magnetic fields found in the man-made environment.

Study character:

Study funded by

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