Note: This study found no significant biological effects under its experimental conditions. We include all studies for scientific completeness.
Effects in Rodents of a 1-Month Exposure to Magnetic Fields (200-1200 Gauss)
Gabriel G. Nahas, Henri Boccalon, Pierre Berryer, Bernard Wagner · 1975
Month-long exposure to strong magnetic fields caused no harm in rats, but unexpectedly increased weight gain in young animals.
Plain English Summary
Researchers exposed rats to magnetic fields between 200-1200 Gauss for one month and found no toxic effects or tissue damage. The only notable finding was that young rats exposed to magnetic fields gained more weight than unexposed rats. The study concluded these field strengths should be safe for human exposure lasting several hours.
Why This Matters
This 1975 study represents early safety research on static magnetic fields, the type used in MRI machines and some therapeutic devices. The field strengths tested (200-1200 Gauss) are thousands of times stronger than typical household EMF exposures, which measure in milligauss. What's particularly interesting is the unexpected weight gain in exposed young rats, suggesting these fields may influence biological processes even when causing no apparent harm. The research limitations are significant though - one month exposure in rats doesn't necessarily predict long-term human safety, and our understanding of EMF biological effects has evolved considerably since 1975. While the study found no acute toxicity, it predates decades of research showing subtler cellular and molecular effects from EMF exposure that weren't measured in this early work.
Figures from the Original Paper
Diagram extracted from the original research document.
Show BibTeX
@article{effects_in_rodents_of_a_1_month_exposure_to_magnetic_fields_200_1200_gauss__g4317,
author = {Gabriel G. Nahas and Henri Boccalon and Pierre Berryer and Bernard Wagner},
title = {Effects in Rodents of a 1-Month Exposure to Magnetic Fields (200-1200 Gauss)},
year = {1975},
}