Study type: Medical/biological study (experimental study)

Influence of 50 Hz magnetic field on human heart rate variablilty: Linear and nonlinear analysis. med./bio.

Published in: Bioelectromagnetics 2004; 25 (6): 474-480

Aim of study (acc. to author)

To compare heart rate signals recorded during 50 Hz magnetic field with heart rate signals acquired under environmental conditions. The exposure system was a commercial device for magnetotherapy.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 1 h
Exposure 2: 50 Hz
Exposure duration: intermittent, 30 min off (sham exposure) followed by 30 min magnetic field exposure

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 1 h
Exposure setup
Exposure source
  • coil(s)
  • magnetotherapy device
Setup The subjects lay on a couch inside the coil (20 cm long x 60 cm in diameter) which was placed at the position of the subject`s hips
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 500 µT unspecified measured - in the center of the coil
magnetic flux density 20 µT minimum measured - at the head position
magnetic flux density 30 µT maximum measured - at the head position
magnetic flux density 150 µT minimum measured - at the heart position
magnetic flux density 200 µT maximum measured - at the heart position

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration intermittent, 30 min off (sham exposure) followed by 30 min magnetic field exposure
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 500 µT unspecified measured - in the center of the coil
magnetic flux density 20 µT minimum measured - at the head position
magnetic flux density 30 µT maximum measured - at the head position
magnetic flux density 150 µT minimum measured - at the heart position
magnetic flux density 200 µT maximum measured - at the heart position

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

Statistical analysis (repeated measures ANOVA) performed for sham exposure (magnetic field-off/magnetic field-off protocol) indicated no statistical difference of heart rate variability data. Repeated measures ANOVA followed by another statistical test (post hoc Tukey test) performed for exposure (magnetic field-off/magnetic field-on protocol) indicated a statistically significant difference during magnetic field on for mean time between heart beats (8% increase), standard deviation between heart beats (40% increase), and pNN50 (110% increase).
The data of the analysis indicate that the changes of these parameters could be associated with the influence of magnetic field.

Study character:

Study funded by

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