Study type: Medical/biological study (experimental study)

Effects of power frequency electromagnetic fields on melatonin and sleep in the rat med./bio.

Published in: Emerg Health Threats J 2012; 5: 10904

Aim of study (acc. to author)

To study the effects of extremely low power frequency magnetic fields on the production of melatonin and the subsequent sleep structure in rats.

Background/further details

9 male rats were exposed and 9 rats were sham exposed. Urine was collected for the final three days (every six hours) of the exposure period.



Exposure Parameters
Exposure 1: 60 Hz
Exposure duration: continuous for 24 h/day for 30 days (except 10 min/day for animal handling)

Exposure 1

Main characteristics
Frequency 60 Hz
Exposure duration continuous for 24 h/day for 30 days (except 10 min/day for animal handling)
Additional info horizontal field
Exposure setup
Exposure source
Chamber 4 m high, 10 m x 4 m room with masonry walls
Setup 243.84 cm (8ft) long Sonotube reinforced cardboard tube with a diameter of 60.96 cm (2 ft), wrapped with 18 gauge insulated copper wire; supported by a 5.08 cm (2inches) high wooden cradle horse; animals placed individually in 30 cm x 22.86 cm x 20.32 cm (12" x 9" X 8") polypropylene cages fitted with 5.08 cm (2 inches) high PVC filters as cover; sham exposure apparatus 7 m apart from the exposure device in the same room
Sham exposure A sham exposure was conducted.
Measurand Value Type Method Mass Remarks
magnetic flux density 0.1 mT - measured - -
magnetic flux density 0.1 µT - measured - for the sham exposure

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

Power frequency magnetic fields induced a marginally statistically significant increase in melatonin levels during the dark period in exposed rats compared to the control. Although there were no statistically significant changes in sleep structure, exposed animals showed slight decreases in REM sleep as compared to sham exposed animals.
The data do not support the notion that magnetic fields reduce melatonin production as suggested by the melatonin hypothesis.

Study character:

Study funded by

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