Radio waves, Wi-Fi and the human body: what science says

Wi-Fi, mobile phones and Bluetooth use radio waves. Parents, teachers and municipalities often ask what they do to the body, and especially to children. Here is what is established, what is still discussed, and why many schools choose to switch the Wi-Fi off when it is not used.

What are radio waves?

Radio waves are electromagnetic fields, like light, but with a much lower frequency. Wi-Fi uses the bands of 2.4, 5 and 6 GHz. They are non-ionising: unlike X-rays or ultraviolet light, they do not carry enough energy to break chemical bonds or to damage the DNA directly.

A Wi-Fi access point emits at most a few hundred milliwatts, less than a mobile phone during a call, and the field decreases quickly with the distance: at a few metres it is a very small fraction of what it is next to the antenna.

The established effect: heating

When the body absorbs radio waves, the energy becomes heat. At high levels, far above everyday exposure, this heating can harm the tissues. It is the only effect that is established with certainty.

The exposure limits of the International Commission on Non-Ionizing Radiation Protection (ICNIRP), followed by the EU recommendation and by most European countries, are set from this threshold, with a safety margin: for the general public, the limit is 50 times below the level where heating effects start. Measurements in classrooms in several European countries show exposures from Wi-Fi that are generally far below these limits, often below one percent of them.

What is still discussed

Cancer. In 2011 the International Agency for Research on Cancer (IARC) classified radiofrequency fields as possibly carcinogenic to humans (group 2B), mainly from studies of heavy users of mobile phones held against the head, an exposure much higher and more local than that of Wi-Fi. This category means that the evidence is limited, not that a risk is proven. In 2024, a systematic review commissioned by the World Health Organization (Karipidis et al.) concluded that mobile phone use is not associated with an increased risk of brain cancer.

Other effects. Studies on sleep, brain activity, cognition or fertility give contradictory results. Some report small effects, others none, and the effects are rarely reproduced. Research continues, especially on the long term.

Children. Children absorb slightly more energy in some tissues, because of the size of their head and the thickness of their skull, and they will be exposed during a longer life. In 2016, the French agency ANSES recommended reducing the exposure of children and, as a precaution, reviewing the margins of the limits for them.

Electromagnetic hypersensitivity

Some people report headaches, fatigue, sleep or concentration problems that they attribute to electromagnetic fields. These symptoms are real and can be disabling. However, in double-blind studies, the people concerned have not been able to tell whether a field was on or off, and the symptoms did not follow the real exposure. The WHO and ANSES (2018) therefore conclude that a causal link with the fields is not established, while recommending that these people are taken seriously and cared for.

Precaution in schools

Because of the remaining uncertainties, several countries apply a principle of precaution, especially for children:

  • France: the Abeille law of 2015 forbids Wi-Fi in the spaces for children under three years, and asks that the Wi-Fi of the primary classrooms is switched off when it is not used for teaching.
  • Norway: the authorities consider that the exposure from Wi-Fi is far below the limits, and recommend that unnecessary exposure is avoided.
  • Belgium: there is no rule for the Wi-Fi in schools, but more and more schools want to control the connection, after the ban of the recreational use of phones in the schools of the Wallonia-Brussels Federation in 2025.

What PoE-Sea changes

PoE-Sea does not claim any medical effect. It does something simple and measurable: when the Wi-Fi is not used, the access point is really off, not in standby, and emits nothing. The exposure in the classroom then falls to zero for this source, the electricity consumption stops, and the network cannot be attacked.

The teacher switches the Wi-Fi on for the activity that needs it, with a battery-free switch, and it goes off by itself afterwards. Precaution becomes a daily habit, without giving up digital tools.

Sources

  • ICNIRP, Guidelines for limiting exposure to electromagnetic fields (100 kHz to 300 GHz), Health Physics, 2020. icnirp.org
  • IARC, IARC classifies radiofrequency electromagnetic fields as possibly carcinogenic to humans, press release no. 208, 2011. iarc.who.int
  • Karipidis K. et al., The effect of exposure to radiofrequency fields on cancer risk in the general and working population: a systematic review of human observational studies, Part I, Environment International, 2024. doi.org/10.1016/j.envint.2024.108983
  • WHO, Radiation: electromagnetic fields (questions and answers). who.int
  • ANSES, Exposition aux radiofréquences et santé des enfants, 2016; Hypersensibilité électromagnétique ou intolérance environnementale idiopathique attribuée aux champs électromagnétiques, 2018. anses.fr
  • Loi n° 2015-136 du 9 février 2015 relative à la sobriété, à la transparence, à l'information et à la concertation en matière d'exposition aux ondes électromagnétiques (loi Abeille). legifrance.gouv.fr

Last updated: 11 Oct 2026. This page summarises public scientific assessments and is not medical advice.