Study type: Medical/biological study (experimental study)

Long-term exposure of Sprague Dawley rats to 20 kHz triangular magnetic fields med./bio.

Published in: Int J Radiat Biol 2006; 82 (4): 285-291

Aim of study (acc. to author)

This study was conducted to investigate the effects of long-term (12 or 18 months) exposure to 20 kHz intermediate frequency magnetic fields on physiological parameters in rats.

Background/further details

80 three-week-old rats were used (half male and female in each sham exposed and exposed groups). The applied magnetic flux density of 6.25 µT represents the exposure limit for the public of 20 kHz magnetic fields in Korea.



Exposure Parameters
Exposure 1: 20 kHz
Modulation type: pulsed
Exposure duration: repeated daily exposure, 8 h/day for 12 or 18 months

General information

Male and females were equally divided into 2 groups for sham and active exposures.

Exposure 1

Main characteristics
Frequency 20 kHz
  • sawtooth-shaped
Exposure duration repeated daily exposure, 8 h/day for 12 or 18 months
Additional info Vertical magnetic field was used for exposure.
Modulation type pulsed
Exposure setup
Exposure source
Measurand Value Type Method Mass Remarks
magnetic flux density 6.25 µT effective value measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The body weight was significantly reduced in both male and female rats of the 18 months exposure group. Blood examinations revealed significantly increased number of neutrophils after 12 months exposure, and significantly decreased number of lymphocytes in the 18 months exposure group, but only in female rats. Other investigated parameters were unaffected.
In conclusion, these results indicate that long-term exposure of rats to 20 kHz magnetic fields do not induce any significantly harmful effects, except changes in neutrophils and lymphocytes in female rats. These hematological changes need to be further investigated.

Study character:

Study funded by

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