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Sleep & Circadian RhythmPart of the Glaser Archive

A Failure to Detect an Influence of Magnetic Fields on the Growth Rate and Circadian Rhythm of Neurospora crassa

No Effects Found

D. Michael Bitz, Malcolm L. Sargent · 1974

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Early magnetic field research found no circadian effects in bread mold, but modern studies show human biological clocks are far more EMF-sensitive.

Plain English Summary

Summary written for general audiences

Researchers exposed Neurospora crassa (bread mold) to low-strength magnetic fields of 6.36 and 32.25 gauss using continuous, pulsed, and cycling exposure patterns. The study found no significant effects on the organism's circadian rhythm or growth rate. This represents early research into whether magnetic fields can disrupt biological timing mechanisms.

Why This Matters

This 1973 study represents some of the earliest systematic research into magnetic field biological effects, focusing on circadian rhythms - our internal biological clocks. While the researchers found no effects on this simple organism, the magnetic field strengths tested (6.36 to 32.25 gauss) are actually quite strong compared to typical household exposures, which rarely exceed 1-2 gauss even near major appliances.

What makes this research particularly relevant today is its focus on circadian disruption, an area where modern EMF research has found much stronger evidence for effects. The science demonstrates that while simple organisms like bread mold may show resilience to magnetic fields, more complex biological systems - including humans - appear far more sensitive to EMF-induced circadian disruption, especially from the radiofrequency radiation our devices emit today.

Finding

Low strength magnetic fields, 6.36 and 32.25 gauss, were found to have no effect, with one questionable exception, on the circadian rhythm and growth rate of Neurospora crassa. This was true whether the fields were continuous, pulsed 20 minutes daily, or on a 12:12, on-off cycle.

In their words

“Low strength magnetic fields, 6.36 and 32.25 gauss, were found to have no effect, with one questionable exception, on the circadian rhythm and growth rate of Neurospora crassa. This was true whether the fields were continuous, pulsed 20 minutes daily, or on a 12:12, on-off cycle.”
Cite This Study
D. Michael Bitz, Malcolm L. Sargent (1974). A Failure to Detect an Influence of Magnetic Fields on the Growth Rate and Circadian Rhythm of Neurospora crassa.
Show BibTeX
@article{a_failure_to_detect_an_influence_of_magnetic_fields_on_the_growth_rate_and_circa_g5896,
  author = {D. Michael Bitz and Malcolm L. Sargent},
  title = {A Failure to Detect an Influence of Magnetic Fields on the Growth Rate and Circadian Rhythm of Neurospora crassa},
  year = {1974},
  
  
}
No DOI on file for this study.

Quick Questions About This Study

Researchers tested two magnetic field strengths: 6.36 gauss and 32.25 gauss. These are relatively strong fields compared to typical household EMF exposures, which usually measure under 2 gauss even near major appliances like refrigerators or hair dryers.
No, this study found that magnetic fields had no effect on Neurospora crassa's circadian rhythm, even with continuous exposure or various pulsing patterns. However, bread mold is a very simple organism compared to humans and other complex life forms.
Scientists tested three different exposure patterns: continuous magnetic fields, pulsed fields for 20 minutes daily, and fields cycling on a 12:12 hour schedule. None of these patterns affected the organism's growth or biological timing.
Neurospora crassa (bread mold) was chosen because it has a well-documented circadian rhythm and grows quickly, making it ideal for studying whether magnetic fields can disrupt biological timing mechanisms. It's a simple model organism for basic research.
Early studies like this focused on static magnetic fields and simple organisms, finding few effects. Modern research examines radiofrequency radiation from wireless devices on complex biological systems, revealing much stronger evidence for circadian disruption and other health impacts.