Biological studies on extremely low frequency electromagnetic fields (ELF-EMF) can generally investigate two different aspects: health risks or clinical application. The frequency at which power grids operate (60 Hz North America; 50 Hz Europe, Asia, Australia, large parts of Africa and parts of South America) is considered particularly important due to the nationwide distribution of electricity. ELF-EMFs are associated with both health risks and therapeutic effects such as wound healing or stimulation of bone growth. The authors of this publication investigated an interesting approach to a clinical application, namely stress reduction by 50 Hz and 60 Hz ELF-EMF. Controversial studies on this topic exist. Different working groups found increased, decreased and constant stress levels after ELF-EMF exposure. The stress level of the test animals is measured as the glucocorticoid (GC) level in blood serum. Increased GC levels are a marker for the general physiological state of stress. The aim of the present study was to investigate stress-reducing effects of ELF-EMF in three different scenarios. i) frequencies of 50 and 60 Hz; ii) different ambient illuminance levels; iii) partial or complete shielding of the test animals from ELF-EMF.
As experimental animals, 8-week-old male BALB/c mice were used. The exposure system consists of three main components: a high-voltage transformer, a DC voltage unit and a parallel plate electrode system. The EMFs operated at 10 kV/m for both frequencies. Only the upper electrode generated EMFs; the lower electrode was grounded. Stress was induced in the mice by immobilizing them in a 50-ml centrifuge tube. The immobilization was always performed in the second 30 minutes of the 60-minute EMF test. For the first experiment (effect of ELF-EMF on immobilization stress), the animals were divided into 6 groups with 6 mice each: one control group [stress (-)/EMF (-)], two groups with exposure only but no immobilization [stress (-)/EMF (50 Hz/60 Hz)], one immobilized group [stress (+)/EMF (-)] and two groups with both stress induction and EMF exposure [stress (+)/EMF (50 Hz/60 Hz)]. The stress levels of the experimental animals were determined by their GC levels in blood plasma.
There were no significant differences in plasma GC levels between the two “exposure only” and the control groups. GC levels of immobilized mice were significantly higher than the control group. The GC levels of the two groups that were both immobilized and exposed to ELF-EMF fell between those of the control group and the immobilized group. This indicates that both 50 and 60 Hz ELF-EMFs at 10 kV/m are able to reduce stress levels in experimental animals. In the second experimental setup, the effect of ambient illuminance levels on stress reduction caused by ELF-EMF was addressed. The same experimental procedure was followed, but this time at defined illuminance levels of 0 lux, 200 lux and 490 lux. At 200 lux, a reduction of stress could be observed due to the exposure to ELF-EMF in the EMF + immobilization group compared to the stress-only group. However, no correlation between stress level and illuminance level was found in the control groups or the stress-only group. In the third experimental setup, the centrifuge tubes, which served as immobilization devices, were shielded with polytetrafluoroethylene in various proportions. 5 mm, 20 mm, 80 mm and 200 mm were shielded. 5 mm represented a small fraction of the mouse body, 20 mm approximately ¼ of the mouse body, 800 mm the entire mouse body and 200 mm the entire mouse body including the tail. The partially shielded mice (5 mm and 20 mm) showed lower GC levels than the stress-only group during the simultaneous treatment with immobilization and EMF. At 80 mm or 200 mm shielding, respectively, the GC levels were comparable to those of the stress-only group.
The results of the scientists show the biological effect of ELF-EMF on the hormonal system of mice under acute stress. According to the authors, the attenuating effect of ELF-EMF is a promising candidate for the treatment of stress-related diseases. However, more experiments are necessary to test the long-term effects of ELF-EMF on biological systems in particular.