There are many websites out there that list “the world’s most dangerous inventions”, but one in particular has caught my eye. So, what creation does it reward with this ominous title? Nuclear weapons perhaps? Cigarettes? Maybe motor cars? No, none of these – the world’s most dangerous invention is apparently shoes.
Some people believe that isolating ourselves from the Earth by wearing shoes, or indeed even being indoors, causes illness. They argue that you get health benefits by maintaining physical contact with the planet, because you are exchanging electrons with the surface and keeping your body at “Earth potential”. To back their reasoning, these “earthing” supporters claim that primitive people didn’t suffer from today’s illnesses because they didn’t wear shoes and they slept on the ground. (Mind you, life for primitive people was extremely short and hard so it’s difficult to say whether earthing was of benefit to them.)
A whole industry has built up to supply household items with metal wires woven into them and earthed to keep us grounded
The anti-shoe brigade therefore encourage us to walk barefoot outdoors or stay “electrically connected” to the Earth in some other way. Indeed, a whole industry has built up to supply household items with metal wires woven into them and earthed to keep us “grounded” – this includes everything from bedsheets, pillows and footrests to yoga mats and shoes with copper contacts on the soles. You can even buy an earthed mat for your dog to sit on.
Results have been published in science journals, apparently showing that grounding improves mood, quality of sleep and immune function, while reducing stress and tension, and producing other health benefits. In one study published in Psychological Reports: Mental & Physical Health (116 534), 40 subjects were randomly assigned to relax on a comfortable chair fitted with carbon-fibre pads, some of which were earthed and some were not. Those subjects who were earthed reported higher pleasant and positive moods compared with the unearthed control group.
The devices designed to keep you at Earth potential use the earthing circuit of your house wiring and have a 100,000 Ω resistor in the cable. Manufacturers don’t explain the purpose of the resistor but it is presumably a safety device to suppress any current surge. For example, if for any reason your house circuit is not properly earthed then, should a fault develop in the house wiring, an earthed bed sheet would become live at mains potential and you could be electrocuted, which would detract somewhat from the healthy image the companies are trying to present for these products.
One of the pro-earthing websites states: “Just as the Sun gives us warmth and vitamin D, the Earth underfoot gives us food and water, a surface to walk, sit, stand, play and build on, and something you never ever thought about – an eternal, natural and gentle energy. Think of it as vitamin G – G for ground. What does that mean to you? Maybe the difference between feeling good and not so good, of having little or a lot of energy, or sleeping well or not so well.”
In practice it’s hard to understand why connecting your body to Earth would have any effect at all. When shuffling across a carpeted floor you lose (or gain, depending on the materials involved) several billion electrons but as soon as you touch an earthed metal object you get them all back (or give them all up).
Even if you don’t touch an earthed metal object you won’t stay charged for long. Most materials conduct electricity to a greater or lesser extent, and certainly all those you encounter day-to-day, including sheets and blankets, will have some level of conductivity. All shoes, even those with plastic soles, have a degree of conductivity, as those unfortunate people who were wearing shoes when they received electric shocks can confirm. It’s simply not possible to maintain a significant charge imbalance between your body and the rest of the world. All day every day all of us are grounded already.
The published studies demonstrating the claimed benefits of earthing deserve careful reading. In the Psychological Reports paper, for example, there were 27 subjects in the treated group and 13 in the control group. These numbers are too small to reach a definitive conclusion, and the researcher has introduced the extra complication of having two groups of different sizes. Some of the publications are also found in unreviewed pay-to-publish journals, or journals devoted to alternative medicine, and therefore can lack the proper scientific rigour to back them up.
One article written by a believer in earthing talked about “beneficial electrons from the Earth flowing into your body and producing healing”. Someone then wrote a rather tongue-in-cheek response in the comments section:
“There is an excellent source of free electrons – indeed you can get a lifetime’s supply or more in a millisecond! With my patented copper Electron Capture Pole, you can now gather copious free electrons directly from a height of 15,000 metres in cumulonimbus clouds! Gather the purest free electrons from high in the upper atmosphere! It’s everything you need to create the perfect connection between you, the sky and the Earth! You’ll be more grounded than you could ever imagine possible! It’s like literally touching the sky!”