Robyn Williams: We began today with an Infinite Monkey Cage on the Woo factor – how people can be bothered about unfamiliar technology. Well, what about WiFi, radio, those screens you won’t put down, refuse ever to put down? What about a laptop when the lap belongs to a pregnant woman, does such radiation reach the foetus? Well, Signe Dean is a science writer and she too has her suspicions.

Signe Dean: I used to get a lot of headaches. Every week, on more days than not, I'd wake up with some degree of pain.

Over-the-counter painkillers did help somewhat, but I didn't know what was causing the headaches to begin with.

So I started looking for correlations. Was it the occasional gin and tonic with dinner? Lack of sleep hours? Perhaps hormones?

I started a calendar logging headaches and possible triggers. This is a strategy chronic migraine patients use quite often — it helps doctors adjust treatment plans.

But for me the calendar didn't reveal any patterns. I simply didn't know what was going on, and my GP couldn't help, either.

Millions of people live with chronic health issues. For many that means having a diagnosis, a management plan, and, perhaps, prescription meds. These days evidence-based medicine is pretty good at helping people with all kinds of illnesses. But it's not foolproof.

Sometimes evidence is elusive.

People with mystery symptoms - like my headaches - may start looking in weird places to explain what's making them miserable.

For example, I could have blamed my new smartphone.

In fact, many people do blame technology for their ailments.

To understand what they mean, we need to step back a little and look at electro-magnetic radiation.

It's a phenomenon that's been around since the birth of the universe, and it occurs on a spectrum. One type of electro-magnetic radiation is visible light; microwaves are another; and then there are also X-rays and radio waves, and infrared, and so on.

What it comes down to is that there are invisible electro-magnetic fields everywhere in the world.

In fact, we're all bathed in this kind of radiation from the moment we are born. The naturally occurring type largely comes from space. The rest — well, there are many man-made sources.

Everything that's electric also has an associated low frequency electro-magnetic field. Your toaster and hair dryer are both good examples, and so is your desk lamp.

Meanwhile TV antennae, radio stations and mobile towers emit higher frequencies.

So, should you be worried? Isn't radiation bad?

In short, yes and no, although mostly — no. The bad kind of radiation only happens at very high frequencies, at which the emitted energy is powerful enough to break molecular bonds. In other words, it's called ionizing radiation, and it's what makes radio-active stuff so dangerous.

Electric things and wireless things work at a much, much lower frequency, and the waves they emit are known as non-ionizing radiation.

And, if you remember, that stuff is everywhere, and is generally deemed pretty harmless.

The World Health Organisation has extensive documentation on electro-magnetic fields and public health. They are referring to some 25 thousand scientific publications over the past 30 years.

Their conclusion? Current evidence doesn't confirm the existence of any health consequences from exposure to low level electro-magnetic fields.

But — unless you're really good at understanding physics, it's still easy to get confused about all this radiation, wavelengths, frequencies and so on.

If microwaves can boil water, how come mobile phones aren't dangerous? And even if there's always been a low level of exposure to electro-magnetic fields, isn't there so much more of it in the modern world? Shouldn't we be worried about all these devices emitting stuff we can't see?

Following exactly this line of reasoning, some people believe danger might indeed be present -- in the shape of WiFi routers, computers, smartphones, and yes, even toasters.

After all, our modern lifestyle is terribly unhealthy, isn't it?

That quiet unease of living in an age when technology develops at a blistering speed can leave us dizzy and uncertain. Add a dash of misinformation and some colourful headlines, and we arrive at what can only be termed as techno-phobia.

Take this one: "Brain on fire"! That's the title of a recent lifestyle magazine story about the lives of people who claim to have a syndrome called electro-magnetic hyper-sensitivity.

It's a mouthful, I know, so I'll shorten it to EHS.

The claim is that for a small number of people in the population, exposure to electro-magnetic fields causes chronic health problems. Symptoms range from pains and aches, to depression, to sleep troubles, nausea, tinnitus, fatigue and also… headaches.

According to the World Health Organisation, EHS is a bunch of non-specific symptoms which are not part of any recognised syndrome.

Not all people who think they have EHS are affected in the same way. For some it appears that only WiFi causes problems, while others cannot tolerate any type of electro-magnetic field whatsoever.

Now, there's no official diagnosis of electro-magnetic hypersensitivity, and it's actually difficult to judge how many sufferers there are. People who believe they have EHS are usually self-diagnosed and often experience stress because nobody seems to know what is wrong with them.

When I was dealing with my mystery headaches, it could get quite stressful, too -- and often upsetting, because I wanted to get rid of them, but didn't know how.

We all want to feel healthy, or at least, as healthy as we can. But if you don't know what's making you sick, how do you cope?

As humans, we naturally seek patterns and explanations for the world around us. Everything needs to fit into a narrative. What we experience needs to make sense. So if you're feeling unwell a lot of the time, but doctors can't find a cause, and then you learn that other people with similar symptoms blame electrical devices — well, at least it's an explanation?

Given the pre-conceptions I mentioned earlier -- how we feel about technology and radiation, EHS is actually an easy sell.

It kind of does make sense — provided you don't know that extensive scientific research basically rules it out, because there's no biologically plausible mechanism for the illness.

I want to stress here that the symptoms people experience are undeniably real. Sufferers of EHS often drastically change their lives -- they lose jobs, and sometimes can't even function in a modern society. I mean, imagine if you couldn't have WiFi in your house or work anywhere near computers.

It's only when you start paying attention to the low-level radiation all around us that you realise — it's extremely difficult to avoid electro-magnetic fields. People go to great lengths to coat their homes in special paint, and to avoid all electronics.

People with severe EHS symptoms often move to the countryside and even form special communities in far-away places with low electro-magnetic exposure. In the United States’ National Radio Quiet zone there’s a tiny hill-top town called Green Bank, where several dozen self-diagnosed people have flocked from across the country.

Here they can live un-touched by the tight network of waves that carry cat pictures, Twitter updates and radio news through the very air that we breathe.

Even though a reclusive retreat away from screens and phone calls might sound appealing, life gets pretty difficult without the standard of technology we are all used to.

And the sad part is that EHS sufferers are retreating for the wrong reasons.

In the story about burning brains I mentioned earlier, there's a telling anecdote. An EHS sufferer - let's call him John - checks the little radio-frequency meter he carries with himself everywhere. The numbers show that the location where he's driven with the reporter has a lot more radiation than he deems safe.

Five minutes later he starts complaining about pressure in his head.

But would his head have started hurting had he not looked at the meter? In a scientific test John would be randomly exposed to electro-magnetic radiation without knowing when, and he'd have to report whether he can feel a difference.

Such tests have been done, and they show that EHS sufferers' symptoms don't actually correlate with exposure.

Instead, they might be experiencing the placebo effect’s lesser known brother, the nocebo effect. It's when a person's expectations about something negatively influence how it will affect them. If John thinks that electro-magnetic fields are harming his health, he could actually get a headache -- because he thinks he's been exposed.

That's not to say it's all in John's head, though. It's more than likely that some of the EHS sufferers are truly ill with another sickness altogether, and it's a case of false self-diagnosis.

But when you have a mystery disease, any explanation is better than none. I spent months avoiding caffeine and alcohol, but my head kept hurting. Then I went to a dentist who by chance spotted a correlation between my sore jaw and frequent painkiller use. She diagnosed me with bruxism, which is a fancy way of saying I clench my teeth when I sleep. This sometimes causes strong, even debilitating tension headaches.

I've since learned that bruxism is extremely common, and many of my friends and acquaintances also have it. Now I wear a helpful nightly mouthguard.

A lot of my thinking about the source of my headaches was mistaken - it was based in decent reasoning, but the facts didn't support the conclusion.

It's the same with EHS. People are sick, and they think they've found a cause — but scientific facts don't support that.

In the meantime there's no shortage of stories about people with weird illnesses. It's probably because we are all fascinated by stories of rare ailments, or recluses, or simply any yarn that goes against the conventional narrative thread. Perhaps its curiosity, and perhaps there's that tantalising element of mystery too.

But when it comes to public health, subjectivity is harmful, and an interesting story simply isn't enough. A lot of the parents who refuse vaccination do so because they've been misled. People who advocate against wind turbines think that there are health concerns when none are present. Just as well, people with self-diagnosed electro-magnetic hyper-sensitivity are making life choices that are unlikely to heal them. What they need instead is better diagnostic and mental health care.

No human is protected from mis-information, and we all make lots of false conclusions, all the time. What's important is to be aware of this shortcoming, and keep examining the facts.

When it comes to staying safe and living a healthy life, it's by far the best to go with evidence-based reasoning. It's the safest tool we have to make good decisions – and figure out mystifying headaches.

Robyn Williams: A sceptical view of low level radiation from Science writer Signe Dean. Back a few weeks ago a rather more concerned view was put by Devra Davis from the US and brain surgeon Charlie Teo who spoke at the University of New South Wales. Next week Ockham’s Razor is presented by Nick Davis who wants to tell you about the Zillion Year City. I’m Robyn Williams.