Possible cause for altered spatial cognition of prepubescent rats exposed to chronic radiofrequency electromagnetic radiation.
Narayanan SN, Kumar RS, Karun KM, Nayak SB, Bhat PG · 2015
At a Glance
Of the 258 peer-reviewed studies in this collection on radiofrequency exposure, 199 — 77.1% — reported biological effects. None studied classroom WiFi and children's health directly. The applicable human work measured cognition in adults: a 915 MHz exposure altered choice reaction time, and residents near base stations at exposures far below legal limits showed effects on wellbeing and performance their investigators could not rule out. The physical case for treating children separately rests on measurements showing tissue properties governing absorption change with age.
Based on analysis of 266 peer-reviewed studies
Schools have rapidly adopted WiFi technology, exposing children to radiofrequency electromagnetic fields for 6-8 hours daily throughout their developmental years. This widespread exposure has prompted researchers to investigate potential health effects specific to children.
Children are not simply small adults when it comes to EMF exposure. Their skulls are thinner, their brain tissue has higher water content, and their nervous systems are still developing. These factors may make children more susceptible to any effects of RF-EMF exposure.
Here we examine the research on children, WiFi-frequency radiation, and health outcomes relevant to the school environment.
Key Findings
- -199 of 258 studies (77.1%) in this collection found biological effects from radiofrequency exposure
- -No study in this collection measured classroom WiFi against children's health outcomes — the school-specific question is unstudied here
- -Tissue dielectric properties decrease with age, most markedly in brain, skull and skin, measured across ten tissues at six ages from 130 MHz to 10 GHz (Peyman 2001)
- -Cognitive effects at low exposure are documented in adults but are not uniformly negative — a 915 MHz signal changed choice reaction time, making it faster, with no change to word, number, picture or spatial memory across 36 subjects (Preece 1999)
- -Residents near base stations showed effects on wellbeing and cognitive performance at measured exposures far below recommended limits — maximum 4.1 mW/m² across 365 subjects — with the mechanism at those levels unknown (Hutter 2006)
What the Research Shows
What the Research Covers
Of the 258 peer-reviewed studies indexed here on radiofrequency exposure, 199 — 77.1% — reported measurable biological effects. None of them put a WiFi access point in a classroom and followed the children. The school question has to be assembled from studies of comparable exposures in adults, animal work on brain tissue, and measurements of how absorption varies with age.
Why Children Are Treated as a Separate Case
Peyman and colleagues (2001) measured the dielectric properties of ten rat tissues at six different ages across 130 MHz to 10 GHz, and found a general decrease with age that was most apparent in brain, skull and skin — a consequence of falling water content and changing organic composition. Dielectric properties determine how radiofrequency energy travels into and deposits within tissue, so younger tissue interacts with these fields differently. That is the measured foundation under the familiar claim that children absorb more, and it is animal tissue data rather than a measured dose to a child's head.
Cognition Under Radiofrequency Exposure
Preece and colleagues (1999) gave 36 subjects a randomized three-way cross-over protocol with about 1 W mean power at 915 MHz from an antenna mounted beside the head. One test changed: choice reaction time, which got faster. Word, number and picture recall and spatial memory were unaffected. An effect on the brain is not automatically an impairment, and this one ran the other way.
Hutter and colleagues (2006) studied 365 people living near ten mobile phone base stations, running cognitive tests and wellbeing questionnaires. Total exposure was far below recommended levels, peaking at 4.1 mW/m², with antenna distances of 20 to 600 meters. The authors concluded that effects on wellbeing and performance could not be ruled out at those very low exposures, while stating plainly that a mechanism at such levels is unknown.
Effects on Brain Tissue
Lai and Singh (1996) exposed rats at 2 mW/cm², a whole-body specific absorption rate of 1.2 W/kg, and found increases in both single- and double-strand DNA breaks in individual brain cells four hours later, with pulsed and continuous-wave exposure producing comparable effects.
The collection also holds childhood epidemiology on non-radiofrequency fields: a 1979 study of electrical wiring configurations and childhood cancer and a 2018 meta-analysis of parental occupational exposure to extremely low frequency magnetic fields and childhood nervous system tumor risk. Both are held with title and metadata only, and both concern power-frequency fields rather than WiFi.
What a Classroom Actually Delivers
A classroom access point sits meters away, not against the head, and transmits in bursts driven by network traffic. That is a far smaller exposure than a phone held to the ear. What distinguishes it is duration and population: six or more hours a day, five days a week, across the years when the tissue differences above are largest, applied to children who did not choose the exposure. Duration and consent, rather than intensity, are what make school WiFi a distinct policy question.
What the Evidence Does Not Show
No study here links classroom WiFi to a health outcome in children. The cognitive findings are in adults, small, and in one case positive. The DNA findings are in rats at exposures above classroom levels. The research does not prove that school WiFi harms children, and the gap in it is not proof of safety either.
Reasonable Steps for Schools
The measures that follow are unglamorous and cheap. Mount access points high and away from where children sit rather than on desks or walls beside seating, since distance does most of the work. Use wired connections for fixed equipment. Switch access points off when rooms are unused and outside teaching hours. None of these require choosing a side in the scientific argument.
Related Studies (266)
Cognitive Impairment and Neurogenotoxic Effects in Rats Exposed to Low-Intensity Microwave Radiation
Deshmukh PS et al. · 2015
Researchers exposed male Fischer rats to microwave radiation for 180 days at 3 different frequencies, namely, 900, 1800 MHz, and 2450 MHz. The study investigated effects on cognitive function, heat shock protein 70 (HSP70), and DNA damage in rat brain. The results showed declined cognitive function, elevated HSP70 level, and DNA damage in the brains of microwave-exposed animals. The researchers concluded that chronic low-intensity microwave exposure in the frequency range of 900 to 2450 MHz may cause hazardous effects on the brain.
Cancer & TumorsNo Effects Found
Exposure to Radio-Frequency Electromagnetic Fields From Broadcast Transmitters and Risk of Childhood Cancer: A Census-based Cohort Study.
Hauri DD et al. · 2014
Swiss researchers analyzed 4,246 childhood cancer cases among children living in Switzerland between 1985 and 2008 to see if living near radio and TV broadcast towers increased their cancer risk. They found no increased risk of childhood leukemia and mixed results for brain tumors, with their most comprehensive analysis showing no association. This large population study suggests that RF radiation from broadcast transmitters does not significantly increase childhood cancer rates.
Brain & Nervous SystemNo Effects Found
Effects of early-onset radiofrequency electromagnetic field exposure (GSM 900 MHz) on behavior and memory in rats.
Klose M et al. · 2014
German researchers exposed young rats to cell phone radiation (900 MHz) for nearly their entire lives, testing their learning and memory abilities at different ages. Despite using radiation levels up to 10 W/kg (much higher than typical phone exposure), they found no significant effects on behavior, memory, or brain development. This long-term study suggests that chronic cell phone radiation exposure starting in early development may not impair cognitive function.
Mobile phone use and health symptoms in children.
Chiu CT, Chang YH, Chen CC, Ko MC, Li CY. · 2014
Researchers surveyed over 2,000 Taiwanese children aged 11-15 to examine whether mobile phone use was linked to health symptoms. They found that children who used mobile phones had 42% higher odds of experiencing headaches and migraines, and 84% higher odds of skin itching compared to non-users. Parents also reported that regular phone users had worse overall health compared to the previous year.
Brain & Nervous System116 citations
Association between mobile phone use and inattention in 7102 Chinese adolescents: a population-based cross-sectional study.
Zheng F et al. · 2014
Researchers studied over 7,000 Chinese middle school students to examine whether mobile phone use affects attention span. They found that students who used their phones for entertainment more than 60 minutes daily showed significantly higher rates of inattention symptoms similar to ADHD. The study suggests limiting phone use to under an hour per day may help adolescents maintain better focus.
Mobile usage and sleep patterns among medical students.
Yogesh S, Abha S, Priyanka S. · 2014
Researchers studied 100 medical students to see if heavy mobile phone use affected their sleep quality. Students using phones more than 2 hours daily experienced significantly more sleep problems, including difficulty falling asleep, frequent nighttime awakenings, and daytime fatigue. The effects were particularly pronounced in female students and those who used phones in the evening.
Effects of mobile phone radiation (900 MHz radiofrequency) on structure and functions of rat brain
Saikhedkar N et al. · 2014
Researchers exposed young rats to 900 MHz cell phone radiation for 4 hours daily over 15 days to study brain effects. The exposed rats showed increased anxiety, poor learning and memory, damaged brain cells in key memory regions, and signs of cellular stress from harmful molecules called free radicals. This suggests that prolonged cell phone radiation exposure may damage the brain areas responsible for learning and memory.
Does exposure to GSM 900 MHz mobile phone radiation affect short-term memory of elementary school students?
Movvahedi MM et al. · 2014
Researchers exposed 60 elementary school children (ages 8-10) to cell phone radiation for 10 minutes and tested their reaction times and memory performance. Surprisingly, the children performed better on short-term memory tests after radiation exposure compared to sham exposure. This unexpected finding challenges assumptions about how radiofrequency radiation affects developing brains.
The relationship between NMDA receptors and microwave-induced learning and memory impairment: A long-term observation on Wistar rats.
Wang H et al. · 2014
Eighty Wistar rats were exposed to a 2.856 GHz pulsed microwave source at power densities of 0 mW/cm2 and 50 mW/cm2 for 6 minutes, and then observed at multiple time points up to 18 months after exposure. The microwave-exposed rats showed consistent deficiencies in spatial learning and memory. The level of amino acid neurotransmitters decreased after microwave radiation, and the ratio of glutamate and gamma-aminobutyric acid significantly decreased at 6 months. The hippocampus showed varying degrees of degeneration of neurons, and NR1 and NR2B expression showed a significant decrease, especially NR2B expression.
Nonthermal Effects of Lifelong High-Frequency Electromagnetic Field Exposure on Social Memory Performance in Rats.
Schneider J, Stangassinger M · 2014
Researchers exposed male and female rats continuously to either 900-MHz GSM or 1.966-GHz UMTS electromagnetic fields at 0.4 W/kg. Memory was assessed using a social discrimination procedure, with differences in sniffing duration to familiar and novel juvenile rats used as the measure. EMF-exposed females showed no differences in sniffing duration compared with controls, but sniffing durations of EMF-exposed males at 3 months of age were significantly affected. At 6 months of age, GSM-exposed male adults showed a memory performance deficit, but UMTS-exposed males did not.
Maternal mobile phone exposure alters intrinsic electrophysiological properties of CA1 pyramidal neurons in rat offspring
Razavinasab M, Moazzami K, Shabani M · 2014
Researchers exposed pregnant Wistar rats to 900 MHz pulsed-EMF irradiation for 6 hours per day during gestation, then tested the offspring using behavioral, histological, and electrophysiological methods. Mobile phone exposure was associated with a decrease in the number of action potentials fired and an increase in the amplitude of afterhyperpolarization in exposed offspring compared with controls. Phone exposure significantly altered learning acquisition and memory retention in both male and female offspring rats compared with control rats. Light microscopy of brain sections showed normal morphology in both control and mobile phone-exposed rats.
Effects of nano-selenium on cognition performance of mice exposed in 1800 MHz radiofrequency fields
Qin F, Yuan H, Nie J, Cao Y, Tong J · 2014
Researchers exposed male mice to 1800 MHz radiofrequency fields at 208 microW/cm2 for 0, 30, or 120 minutes per day for 30 days, while some groups also received nano-selenium by intra-gastric injection. Significant impairments in learning and memory were observed in the RF 120 min group, along with reduced acetylcholine levels and antioxidant enzyme activity and increased GABA, glutamate, and MDA in the brain. Nano-selenium supplementation decreased GABA, glutamate, and MDA levels and increased acetylcholine levels and antioxidant enzyme activities in the exposed mice.
Reduction of Phosphorylated Synapsin I (Ser-553) Leads to Spatial Memory Impairment by Attenuating GABA Release after Microwave Exposure in Wistar Rats
Qiao S et al. · 2014
Researchers exposed Wistar rats, rat hippocampal synaptosomes, and PC12 cells to microwave radiation for 5 minutes at a mean power density of 30 mW/cm2. Spatial learning and memory in rats was assessed using the Morris Water Maze navigation task, and there was a decrease in spatial memory performance after microwave exposure. The expression of phosphorylated synapsin I (ser-553) was decreased at 3 days post-exposure and elevated at later time points, while GABA release from synaptosomes was attenuated. Both microwave exposure and synapsin I silencing reduced GABA release, and the greatest reduction was found when both were combined, indicating a synergetic effect.
Alterations of cognitive function and 5-HT system in rats after long term microwave exposure.
Li H et al. · 2014
Researchers exposed Wistar rats to 2.856 GHz microwaves at power densities of 5, 10, 20, or 30 mW/cm2 for 6 minutes three times a week for up to 6 weeks. Spatial learning and memory, hippocampus structure, brain electrical activity, and neurotransmitter levels were assessed at different time points after the last exposure. The study found dose-dependent memory deficits alongside inhibition of brain electrical activity, hippocampus neuron degeneration, and neurotransmitter disturbances. The researchers suggested that the serotonin system may be involved in the cognitive deficits seen after long-term microwave exposure.
Behavior and memory evaluation of Wistar rats exposed to 1·8 GHz radiofrequency electromagnetic radiation
Júnior LC et al. · 2014
Researchers exposed male Wistar rats to radiofrequency electromagnetic radiation from a GSM cell phone (1·8 GHz) for 3 days. After exposure, behavioral tests including the open field and object recognition tests were performed. The exposed animals did not present anxiety patterns or working memory impairment, but stress behavior actions were observed.
Neuroprotective effects of dietary supplement Kang-fu-ling against high-power microwave through antioxidant action
Hu S et al. · 2014
Researchers exposed male Wistar rats to high-power microwave at 30 mW cm−2 for 15 minutes, then administered the dietary supplement KFL orally once daily for 14 days. KFL reversed high-power microwave-induced memory loss and histopathological changes in the hippocampus of rats. KFL also displayed a protective effect against high-power microwave-induced oxidative stress and activated the Nrf2 signaling pathway and its target genes in the hippocampus.
SAR / Device AbsorptionNo Effects Found0
SAR and temperature distribution in the rat head model exposed to electromagnetic field radiation by 900 MHz dipole antenna.
Yang L, Hao D, Wu S, Zhong R, Zeng Y. · 2013
Researchers used computer modeling to calculate how much radiofrequency energy would be absorbed by rat brains during a 900 MHz cell phone frequency exposure experiment. They found that the exposure levels used in their memory study would not cause any significant temperature rise in the brain tissue. This dosimetry study provided the technical foundation for understanding whether any biological effects found in their related memory research could be attributed to heating or non-thermal mechanisms.
Brain & Nervous SystemNo Effects Found
No increased sensitivity in brain activity of adolescents exposed to mobile phone-like emissions
Loughran SP et al. · 2013
Researchers exposed 22 adolescents (ages 11-13) to cell phone-like radiation at two different power levels for 30 minutes while measuring brain activity and cognitive performance. They found no significant effects on brain waves or thinking abilities compared to fake exposure sessions. This suggests adolescents may not be more sensitive to mobile phone radiation than previously thought.
Brain & Nervous SystemNo Effects Found
Maternal cell phone and cordless phone use during pregnancy and behaviour problems in 5-year-old children
Guxens M et al. · 2013
Dutch researchers studied whether pregnant mothers using cell phones or cordless phones would have children with more behavioral problems at age 5. They followed 2,618 children and found no significant increase in behavioral issues among children whose mothers used phones during pregnancy, even with heavy phone use of 5 or more calls per day. The study suggests that prenatal phone exposure doesn't appear to cause behavioral problems in young children.
Complexities of sibling analysis when exposures and outcomes change with time and birth order.
Sudan M, Kheifets LI, Arah OA, Divan HA, Olsen J. · 2013
Researchers analyzed behavioral problems in over 52,000 Danish children exposed to cell phones before and after birth, comparing siblings within the same family to control for genetic and environmental factors. They found that cell phone exposure was linked to behavioral problems, but the association was strongest in first-born children and actually reversed in later-born siblings. This suggests that changing technology and usage patterns over time can complicate our understanding of EMF health effects.
Mobile phone use, blood lead levels, and attention deficit hyperactivity symptoms in children: a longitudinal study.
Byun YH et al. · 2013
Researchers followed 2,422 Korean children for two years to study whether mobile phone use affects ADHD symptoms. They found that children who used mobile phones for voice calls showed increased ADHD symptoms, but only when they also had high levels of lead in their blood. This suggests that exposure to both lead and phone radiation together may worsen attention problems in children.
Spatial learning, monoamines and oxidative stress in rats exposed to 900 MHz electromagnetic field in combination with iron overload
Maaroufi K et al. · 2013
French researchers exposed rats to cell phone radiation (900 MHz) for one hour daily over three weeks and tested their cognitive abilities using various learning tasks. The rats showed impaired performance on exploratory tasks and changes in brain chemicals, particularly in the hippocampus region crucial for memory. This suggests that even moderate exposure to cell phone radiation can affect brain function and cognitive performance.
Cell phone exposures and hearing loss in children in the Danish National Birth Cohort
Sudan M, Kheifets L, Arah OA, Olsen J. · 2013
Danish researchers followed over 52,000 children from birth to age 7, tracking their cell phone use and hearing ability. They found children who used cell phones had a 21-23% higher risk of hearing loss compared to non-users. This is the first large-scale study to examine whether cell phone radiation might affect children's hearing, though the researchers noted the findings need confirmation from other studies.
The relationship between adolescents' well-being and their wireless phone use: a cross-sectional study
Redmayne M, Smith E, and Abramson MJ · 2013
New Zealand researchers studied 400 teenagers' wireless phone use and health symptoms. Students making over 6 calls weekly had 2.4 times higher headache risk, while wireless headset users showed doubled depression and sleep problems. These findings suggest teen phone habits may impact wellbeing.
What This Means for You
- Children absorb more radiation than adults due to thinner skulls and higher water content in tissues.
- Advocate for wired internet connections in your child's classroom when possible.
- At home, use wired connections for your child's devices and turn off WiFi during homework time.
- Reduce WiFi emissions at home with a signal tamer. WiFi Signal Tamer
Further Reading:
Reduce Your Exposure:
Reduce WiFi EMF in your child's environmentFrequently Asked Questions
No study in this collection measured classroom WiFi against children's health, so research has not answered this directly. What exists is adjacent and mixed: a 915 MHz exposure changed adults' choice reaction time, making it faster (Preece 1999); residents near base stations at very low measured exposure showed effects on wellbeing that investigators could not rule out (Hutter 2006); and tissue properties governing absorption differ with age (Peyman 2001). That combination supports sensible placement rather than removal.
Wired connections eliminate the exposure for any device that does not need to move, which makes them the straightforward choice for desktops, interactive boards and lab equipment. A fully wired school is impractical where tablets and laptops move between rooms. The practical middle is wiring what is fixed, mounting access points high and away from seating, and switching them off outside teaching hours.
The measured support for this is tissue data rather than head-to-head human dosimetry. Dielectric properties — which govern how radiofrequency energy enters and deposits in tissue — decrease with age, most noticeably in brain, skull and skin, because water content falls (Peyman 2001). That study measured rat tissues at six ages. It establishes that young tissue interacts with these fields differently without supplying a percentage for a human child.
This collection indexes peer-reviewed research rather than policy, so it cannot source a list of national rules. What the research supports is the underlying point regulators weigh: exposure limits were built around preventing tissue heating, and the effects reported at low exposures here — wellbeing, cognition, DNA endpoints — are not heating effects.
Further Reading
For a comprehensive exploration of EMF health effects and practical protection strategies, explore these books by R Blank and Dr. Martin Blank.
