Extremely Low Frequency (ELF) magnetic fields are produced by the flow of electrical current. They are measured in milligauss (mG) or microtesla (µT). Unlike electric fields, magnetic fields easily penetrate walls and most materials.
Based on Building Biology Institute guidelines (mG (milligauss)):
See where common exposures fall on the scale:
Showing 486 studies with measured magnetic fields (elf) exposure
Oliver C. Hood et al. · 1972
This 1972 study examined how airport metal detectors and weapons screening systems could interfere with cardiac pacemakers in passengers. The research identified electromagnetic interference risks that could potentially disrupt pacemaker function during security screening. This was among the first clinical investigations into EMF effects on implanted medical devices.
Kavaliers M, Choleris E, Prato FS, Ossenkopp K · 1998
Researchers studied how nitric oxide (NO) and nitric oxide synthase (NOS) influence opioid-induced antinociception in the land snail Cepaea nemoralis, and whether these chemicals play a role in the effects of extremely low frequency (ELF) magnetic field exposure. Pain relief was measured by how long snails took to withdraw their foot from a thermal stimulus of 40°C. Exposure to a 60-Hz magnetic field at 141 μT peak for 15 minutes reduced the enkephalinase-induced antinociception in the snails. The inhibitory effects of the magnetic field were significantly reduced by a nitric oxide synthase inhibitor and significantly enhanced by a nitric oxide releasing agent.
E. Fortunatow · 1968
This 1968 Soviet technical report examined the biological effects of electromagnetic fields, covering both electric and magnetic field impacts on living systems. The research represents early radiobiology work from the Soviet Union during a period when Eastern European scientists were actively investigating EMF health effects. This type of foundational research helped establish the scientific basis for understanding how electromagnetic exposures affect biological processes.
Mohammadi F, Ghanati F, Sharifi M, Chashmi NA · 2018
Exposure to the static magnetic field delayed the G1 to S transition in the cell cycle, accompanied by a decrease in cyclin-dependent kinase A and D-type cyclin. The static magnetic field also increased levels of nitric oxide, hydrogen peroxide, and salicylic acid compared to the control group.
Ayoobi F, Shamsizadeh A, Shafiei SA. · 2017
This study investigated the impact of local extremely low frequency magnetic field (ELF-MF) on sleep and drowsiness in healthy young adults. Minimum reaction time after exposure increased significantly compared to before exposure (P = 0.03), while the mean of the SSS scores was no different compared to that before exposure.
Alcaraz M, Olmos E, Alcaraz-Saura M, Achel DG, Castillo J. · 2014
Researchers exposed mice to a 50 Hz ELM-MF for 7, 14, 21, and 28 d and measured the increase in frequency of micronucleated polychromatic erythrocyte in bone marrow. ELF-EMF exposure increased micronucleated cells more than control but less than X-rays. Antioxidant substances tested did not reduce the genotoxic effect of the ELM-MF, although they reduced damage from ionizing radiation.
El Gohary MI, Salama AA, El Saeid AA, El Sayed TM, Kotb HS. · 2013
Researchers exposed rats to extremely low frequency magnetic fields (the type emitted by power lines and appliances) for 15 days and found these fields significantly altered brain wave patterns, particularly enhancing activity in the right hemisphere. When caffeine was given alongside the magnetic field exposure, it appeared to partially counteract some of the brain changes, especially in areas controlling movement.
El Gohary MI, Salama AA, El Saeid AA, El Sayed TM, Kotb HS. · 2013
Researchers studied how caffeine and extremely low-frequency magnetic field (ELF-MF) exposure affected brain electrical activity in rats over 15 days. Caffeine given at 10 mg/kg caused a reduction in the mean power amplitude of EEG signals across most frequency bands, especially the alpha band (8–12 Hz), and this effect was more evident in motor cortex than in visual cortex. Exposure to ELF-MF at 0.2 mT enhanced mean power amplitude in most EEG frequency bands, with the effect more pronounced in the right hemisphere than the left. When caffeine was given alongside ELF-MF exposure, a large increase in alpha-band amplitude appeared after 5 days at all recording sites.
Amirifalah Z, Firoozabadi SM, Shafiei SA. · 2013
Researchers exposed 10 healthy women to a pulsed extremely low-frequency magnetic field at the central brain areas corresponding to electrodes C3 and C4, then measured changes in EEG activity. After exposure, beta (15-25 Hz), sensorimotor rhythm (13-15 Hz), and theta (4-8 Hz) powers were significantly decreased by 12.0% to 26.6% at 10 Hz in the C3 and C4 regions, compared with values measured during exposure. The study suggests that this technique may be applied in the treatment of anxiety, though further investigation is needed.
Cook CM, Saucier DM, Thomas AW, Prato FS. · 2009
Researchers exposed 32 human subjects to two different pulsed magnetic field sequences that differed in presentation rate, to examine effects on the alpha frequency of the human EEG. Alpha activity was lowered over occipital-parietal regions during Sequence 1 exposure, while alpha activity over the same regions was higher after Sequence 2 exposure. These effects occurred after approximately 5 minutes of pulsed magnetic field exposure.
Canseven AG, Keskil ZA, Keskil S, Seyhan N. · 2007
Researchers tested whether a 50 Hz, 0.2 mT magnetic field given before or after drug administration affected seizures induced by pentylenetetrazol in mice. The magnetic field was generated by a pair of Helmholtz coils and seizures were induced by intraperitoneal injection of pentylenetetrazol at 60 mg/kg. Forty-eight adult female mice were used and latency to seizure, total seizure duration, and mortality were recorded. Neither pre- nor post-drug magnetic field exposure had any effect on seizures or mortality rates.
Canseven AG, Keskil ZA, Keskil S, Seyhan N. · 2007
Researchers tested whether 50 Hz magnetic fields (the type from power lines) could affect seizures in mice, either making them better or worse. They exposed mice to magnetic fields before and after giving them a seizure-inducing drug, measuring how quickly seizures started and how long they lasted. The magnetic field exposure had no effect on seizures whatsoever, suggesting these fields don't influence brain seizure activity at the levels tested.
Liu Y, Weng E, Zhang Y, Hong R. · 2002
Researchers exposed mice to a 50 Hz sinusoidal electromagnetic field at 0.2 mT or 6.0 mT for 2 weeks, and measured markers of the antioxidant system and cell membrane fluidity in brain and liver tissue. Malondialdehyde content in brain and liver increased with exposure, while total antioxidant capability decreased at both field strengths. When electromagnetic field exposure was combined with lead, the researchers observed synergic effects on lipid peroxidation.
Fiorani M et al. · 1997
Researchers investigated the effects of 50 Hz magnetic fields (0.2–0.5 mT) on rabbit red blood cells exposed at the same time to an oxygen radical-generating system, Fe(II)/ascorbate. A 0.5 mT magnetic field had no effect on intact red blood cells, but when cells were already under oxidative stress, exposure caused a significant further decay in hexokinase activity of about 20% and a twofold increase in methemoglobin production. The researchers concluded that the magnetic fields studied were able to potentiate the cellular damage induced in vitro by oxidizing agents.
Mahmoudinasab H, Sanie-Jahromi F, Saadat M · 2016
Researchers designed the study to evaluate the effect of EMFs on the mRNA levels of seven antioxidant genes in human MCF-7 cells. Three exposure patterns were tested at two field intensities, 0.25 mT and 0.50 mT, each with a total exposure time of 30 minutes. The MTT assay showed no cytotoxic effect on MCF-7 cells under any of the three exposure conditions at either field intensity. Under the 15-min-on/15-min-off pattern, the 0.50 mT intensity was associated with more up- or down-regulated genes than 0.25 mT, a statistically significant difference (P=0.041), while no such difference was found for the other two exposure patterns.
Varró P, Szemerszky R, Bárdos G, Világi I. · 2009
Researchers exposed rat brain tissue to 50 Hz magnetic fields at power line levels. The exposure altered how brain cells communicate and increased seizure-like activity. This suggests electromagnetic fields from power infrastructure may affect brain function, though effects appeared temporary.
Varró P, Szemerszky R, Bárdos G, Világi I. · 2009
Researchers exposed whole rats or excised rat brain slices to a 50 Hz electromagnetic field at 250–500 µT to examine effects on synaptic efficacy in the central nervous system. Slices treated directly ex vivo showed a decrease in basic synaptic activity, observed as a diminution in amplitude of evoked potentials. Following whole-body exposure, enhanced short- and long-term synaptic facilitation in hippocampal slices and increased seizure susceptibility in neocortical slices were observed. The researchers noted that the overall changes may strongly depend on the synaptic structure and neuronal network of the affected region, together with the specific spatial parameters and constancy of the EMF.
Shin EJ, Nguyen XK, Nguyen TT, Pham DT, Kim HC. · 2011
Researchers examined whether repeated extremely low frequency magnetic field exposure induces fos-related antigen immunoreactivity in the striatum and nucleus accumbens of mice. Exposure at 0.3 or 2.4 mT for 1 hour per day over fourteen consecutive days significantly induced hyperlocomotor activity and fos-related antigen immunoreactivity in a field intensity-dependent manner. The fos-related antigen immunoreactivity lasted for at least 1 year, while locomotor activity returned near control level 3 months after the final exposure.
Zuo H, Liu X, Wang D, Li Y, Xu X, Peng R, Song T. · 2018
Researchers created an Alzheimer's disease rat model using D-galactose and Aβ25-35 injections, then exposed the animals to 50 Hz and 400 µT ELF-MF for 60 continuous days. ELF-MF exposure partially improved the cognitive disorder and upregulated the levels of RKIP, TAK1, and the RKIP/TAK1 interaction, but downregulated p-IKK levels in AD rats. The researchers suggested that ELF-MF exposure might have a potential therapeutic value for AD.
Sun L, Chen L, Bai L, Xia Y, Yang X, Jiang W, Sun W. · 2018
Researchers exposed human amnion epithelial (FL) cells to a 50-Hz magnetic field and investigated the role of reactive oxygen species (ROS) in magnetic-field-induced clustering of epidermal growth factor receptor (EGFR). When cells were pretreated with ROS scavengers NAC or PDTC before exposure, both the ROS-related effects and the EGFR clustering were inhibited. The researchers concluded that ROS mediates magnetic-field-induced EGFR clustering via ASMase activation.
Feng B, Ye C, Qiu L, Chen L, Fu Y, Sun W · 2016
Human amniotic FL cells were exposed to a 50-Hz magnetic field for different durations or intensities, then incubated with staurosporine for 4 hours. Magnetic field exposure alone had no significant effect on early apoptosis or cell viability. When cells were also treated with staurosporine, magnetic field exposure had a protective effect against early apoptosis, and this effect could be abolished by MPT inhibitors. The anti-apoptotic effect was completely eliminated when Akt was inhibited, suggesting that Akt activation was necessary for the effect.
Feng B, Dai A, Chen L, Qiu L, Fu Y, Sun W. · 2016
Researchers exposed human amniotic epithelial (FL) cells to a 50-Hz magnetic field to investigate the molecular mechanisms behind magnetic field-induced epidermal growth factor receptor clustering. Exposing FL cells to the magnetic field at intensities higher than 0.2 mT for 15 minutes enhanced total reactive oxygen species production. Blocking the NADPH oxidase enzyme with the inhibitor DPI suppressed magnetic field-induced cytoplasmic superoxide production and subsequent EGFR clustering, while mitochondrial superoxide production was not affected.
Feng B, Qiu L, Ye C, Chen L, Fu Y, Sun W. · 2016
Researchers exposed human amniotic epithelial cells to a 50-Hz magnetic field at 0.4 mT and examined mitochondrial permeability, mitochondrial membrane potential, and cytochrome c release. Exposure to the magnetic field at 0.4 mT for 60 min transiently induced mitochondrial permeability transition and Cyt-c release, although there was no significant effect on mitochondrial membrane potential. Cells exposed to the magnetic field showed increased intracellular reactive oxidative species levels and GSK-3β dephosphorylation, and the induced mitochondrial permeability transition was attenuated by a ROS scavenger or GSK-3β inhibitor.
Cheng Y et al. · 2015
Researchers examined the effects of extremely low-frequency electromagnetic fields on hippocampal neural progenitor cells cultured from embryonic and adult ischemic brains. Exposure to ELF-EMF at 50 Hz and 0.4 mT significantly enhanced proliferation in both embryonic and ischemic neural progenitor cells. Neuronal differentiation was also enhanced after 7 days of cumulative ELF-EMF exposure, while glial differentiation was not markedly influenced. The data suggest that ELF-EMF promotes neurogenesis of ischemic neural progenitor cells, possibly through the Akt pathway.
Liu X et al. · 2015
Researchers studied the effects of ELF-EMF exposure on Alzheimer's disease development in rats. The rats were exposed to ELF-EMF at 50 Hz and 400 µT for 60 days. ELF-EMF exposure delayed the weight gain of rats and partially improved cognitive and clinicopathologic symptoms. The researchers concluded that certain conditions of ELF-EMF exposure could delay the development of AD in rats.