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Shield Your Body

Note: This study found no significant biological effects under its experimental conditions. We include all studies for scientific completeness.

Sleep & Circadian Rhythm

Absence of chronic effect of exposure to short-wave radio broadcast signal on salivary melatonin concentrations in dairy cattle.

No Effects Found

Stark KD, Krebs T, Altpeter E, Manz B, Griot C, Abelin T · 1997

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Radio frequency fields caused acute melatonin spikes in cows during re-exposure, suggesting EMF can disrupt circadian rhythms even without chronic effects.

Plain English Summary

Summary written for general audiences

Swiss researchers studied dairy cows living near a powerful short-wave radio transmitter to see if radio frequency radiation affected their melatonin levels (a hormone that regulates sleep cycles). While they found no chronic reduction in melatonin over time, they discovered an intriguing pattern: when the transmitter was turned back on after being off for three days, cows near the transmitter showed significantly higher melatonin levels on the first night of re-exposure. This suggests radio frequency fields may cause acute disruptions to biological rhythms, even if long-term effects aren't apparent.

Study Details

A pilot study was conducted to investigate the influence of electromagnetic fields in the short-wave range (3-30 MHz) radio transmitter signals on salivary melatonin concentration in dairy cattle. The hypothesis to be tested was whether EMF exposure would lower salivary melatonin concentrations, and whether removal of the EMF source would be followed by higher concentration levels.

For this pilot study, a controlled intervention trial was designed. Two commercial dairy herds at tw...

The average nightly field strength readings were 21-fold greater on the exposed farm (1.59 mA/m) tha...

Cite This Study
Stark KD, Krebs T, Altpeter E, Manz B, Griot C, Abelin T (1997). Absence of chronic effect of exposure to short-wave radio broadcast signal on salivary melatonin concentrations in dairy cattle. J Pineal Res 22(4):171-176, 1997.
Show BibTeX
@article{kd_1997_absence_of_chronic_effect_3420,
  author = {Stark KD and Krebs T and Altpeter E and Manz B and Griot C and Abelin T},
  title = {Absence of chronic effect of exposure to short-wave radio broadcast signal on salivary melatonin concentrations in dairy cattle.},
  year = {1997},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/9247202/},
}
PubMed: 9247202

Quick Questions About This Study

Swiss researchers studied dairy cows living near a powerful short-wave radio transmitter to see if radio frequency radiation affected their melatonin levels (a hormone that regulates sleep cycles). While they found no chronic reduction in melatonin over time, they discovered an intriguing pattern: when the transmitter was turned back on after being off for three days, cows near the transmitter showed significantly higher melatonin levels on the first night of re-exposure. This suggests radio frequency fields may cause acute disruptions to biological rhythms, even if long-term effects aren't apparent.