When was the last time you looked at your cellphone? Where is it placed right this moment?

Every day German adolescents spend nearly 3 hours on their phones, and look at them around 135 times. Only 2% of 14 to 20 year olds refrain from having their device in the bedroom, with 23% claiming to have it somewhere in their bed or even under their pillow.

The increasing number of cellphones, perceived need to be contactable 24 hours a day, and the urge to never miss any news, leads to an increase exposure to radiofrequency-electromagnetic fields.

Even though humans have always lived with electromagnetic fields, the intense exposure to them is a phenomenon which has only emerged during the last few decades, starting with the introduction of radar-technology during second world war. Now, the possible effects of radiofrequency-electromagnetic field exposure are a hot topic in science, specifically with regard to its effects on the central nervous system.

Therefore, we should ask ourselves, is it really wise to have a strong source of electromagnetic field right next to our brain during a phone call, or under our pillow for the whole night? The latest findings to these questions will be presented here. First, having a look at signal transmission within the brain and its similarities to electromagnetic fields, then, focussing on the potential effects of radiofrequency-electromagnetic fields on our daily life (cognitive function) and sleep. (Please note: none of these studies discussed were funded by cellphone manufacturers or network providers).

How could radiofrequency-electromagnetic fields influence neuronal activity

The brain consists of approximately 86 billion neurons, which are interconnected by 100-150 trillion synapses. While signals between neurons are conveyed with chemical signals using neurotransmitters, the signals within a neuron are conveyed via changes in the electric potential of the membrane.

Any electrical signal, whether inside a neuron or a wire, can theoretically be disturbed by an electromagnetic field. Therefore, there is a chance that the electromagnetic radiation emitted by a cellphone can disturb or change the electrical voltage in the neurons in the brain. This might cause unwanted changes in signal transmission or even create new signals that would not occur without this influence by the cellphone.

We know that radiofrequency-electromagnetic fields can effect neural signals because researchers and clinicians are already making use of the techniques like transcranial magnetic stimulation and deep brain stimulation. This application of electromagnetic fields, albeit using incredibly strong fields, is applied in the treatment of migraine, Parkinson’s disease, Tourette syndrome and many other neurological and psychiatric disorders.

Radiofrequency-electromagnetic field effects on cognitive function

Apart from the fact that checking e-mails or other messages with your cellphone every 5 minutes is distracting from efficient and productive learning, research was also done on the effects of GSM 900 (a digital network used by cellphones) and UMTS (next network generation after GSM 900) on cognitive function. In these studies, participants were placed close to a device emitting radiofrequency-electromagnetic fields, with the strength simulating a phone call. During exposure, the participants were ask to complete different cognitive tasks.

Studies investigating the effect of radiofrequency-electromagnetic fields on cognitive function delivered inconsistent results. In most studies, EEG data of the active working memory and brain regions related to attention showed no effect in healthy individuals. Interestingly, in studies that found significant effects, the number that showed an improvement in performance during exposure was larger than the number showing impairment! A comprehensive meta-analysis on neurobehavioral effects is needed to provide further evidence for these small effects that might be limited to affected attention and working memory.

Radiofrequency-electromagnetic field effects on sleep

Does the electromagnetic field of a cellphone affect the quality and the duration of sleep? While there is strong evidence that the blue light of the display suppresses melatonin production  thereby shifting the sleep-wake cycle , the observed effects of radiofrequency-electromagnetic fields are less consistent.

This might be partly due to variation in the investigated parameters. Unfortunately, one of the main incongruities in these studies is the time of exposure, varying from 15 minutes before sleep to 8 hours during sleep.

Some studies, exposing their participants to GSM 900, observed no effect compared to the no-exposure condition , while others reported a decrease in total sleep time, as well as reduced sleep efficiency and an increase in wake after sleep onset .

Nevertheless, the majority of studies could not find a general effect of exposing participants to GSM 900 (and UMTS). Notably, one must also take into account that the inconsistent results may not be solely due to differences in the experimental set-up, but could also be caused by differences between individuals.

A recent study from 2016 found significant differences between participants, indicating that there might be people, who are more vulnerable to GSM and UMTS than others. Importantly, this does not automatically imply that there are any health risks for these people, just that they are sensitive to electromagnetic fields.

What should we conclude from this?

After more than 20 years of research, the results investigating the effects of radiofrequency-electromagnetic fields on central nervous system activity are inconclusive. This suggests that more research, with similar/ identical experimental set-up, is required before we can begin to fully understand what, if any, effect our cellphones might be having. But even a handful of studies reporting negative effects, especially with respect to sleep, should create an awareness in society on the responsible use of devices, such as cellphones, which emit radiofrequency-elctromagnetic fields. Special attention should be paid to exposure during sleep, and we should ask ourselves: “Do I need to receive messages during night?”, “Do I really have to carry my phone with me everywhere, around the clock?”.

Of course the effect of radiofrequency-electrmagnetic fields on neuronal activity is but one of many potential problems being investigated by researchers. How does being online 24 hours a day effect your psyche? How does the feeling of responsible for checking your work e-mail from home increase your subjective stress level? Why does without your phone for a few hours make some people nervous or stressed?

The results presented here only report on radiofrequency-electramagnetic field effects at the level of neuronal activity. But even if further studies show that none of this has any significant negative effect on our sleep, cognition and mental health, one might still question, whether there are effects on the cardiovascular system or even if the fields are associated with gene mutation.

Everyone is of course free to decide, whether the 24-hour availability is worth all the potential risks and consequences that might come with it. However, building up healthy habits and some selfdiscipline in this regard should perhaps be considered more often and more seriously, as our brains, contrary to electronics, cannot be replaced.