Humans: A Look Under the Hood
Frances Ashcroft’s book The Spark of Life explores how electrical signals in our body drive everything from thought to movement.
Over drinks at a cocktail party — mine wine, his water — a physicist I know compared his body to a Ferrari. A vintage Ferrari, I thought, raising an eyebrow as he explained how he puts only the purest of fuel in his tank. Well-conditioned human bodies are often compared to fine-tuned machines. It’s an apt metaphor.
We’re carbon-based machines, running on fuel and electricity, like so many other gadgets. I’ve always been curious as to exactly how this works, and found the easy answers rather unsatisfying. We run on energy , which comes from food, but food isn’t what connects my brain to my fingertips, signaling them to tap these strokes on my keyboard. That, it turns out, is electricity. The body. it turns out, is one big electrical generator, cycling through positively charged protons, negatively charged electrons and the Swiss citizens of the particulate world, neutrons (which have no charge).
Protons and neutrons are more or less interdependent, bound together by nuclear force, while the electrons gadfly about — the whole time, a lot of promiscuous swapping going on, as neutrons free up, become unstable and decay (causing radioactivity). Alas, as with many wacky, late-stage divorcees, free neutrons are unstable. Varying combinations of this trio form the atom.When the number of protons and electrons is not equal, the atom has a positive or negative charge (and is known as an ion).
Congratulations! If you read the preceding paragraph you partook in a discussion of nuclear physics! Which is more than most people can say each day. But we digress… back to body basics. Against the backdrop of frisky particle exchange going on between protons and neutrons, atoms become unbalanced, taking on either a positive or negative charge, setting the stage for the hovering electrons to flow from one atom to another like busy commuters on the 405. This flow of activity is powered by the body breaking-down to molecular level the foods we eat. Basically, the atomic deconstruction of our food reshuffles the atomic deck in a manner resulting in the production of energy or the storage of fuel for later use (fat).
Our bodies are chemical reactors. Chemical reactions rely on altering the relationship between atoms, rather than wholesale transformation of the atomic nuclei. While there is a bit of nuclear reaction that takes place within our bodies, it’s not useful (and even detrimental).
This interesting health website features a concise video covering the body’s conversion of food into electrical energy. One of the more startling revelations from the accompanying article is that the Earth actually “carries an enormous negative charge,” making it an electron-rich source of antioxidants and free-radical thwarting electrons. “There’s a constant flow of energy between your body and the Earth. When you put your feet on the ground, you absorb large amounts of negative electrons through the soles of your feet,” according to Mercola.com. So barefoot yoga on sand or grass has quantum benefits.
This article at HowStuffWorks.com offers a very thorough explanation of how, specifically, the body generates electricity, relying on interplay between sodium and potassium ions — the sodium-potassium gate (also covered in the above-referenced video). For those curious as to whether human bodies could power machines, a la the Matrix, its a topic of rich discussion at SciFi.StackExchange.com (and the answer is no; the human body is energy-efficient, requiring only about 100 watts of power a day, comparable to running a 100-watt light bulb.
In her book The Spark of Life, Frances Ashcroft details how electricity drives everything we think, feel or do through ion channels that are found in the membranes of each of our cells. “Your ability to hear me now is because there are cells in your ears that are converting sound waves into an electrical signal, which is what the brain can interpret as sound,” Ashcroft — a professor at Oxford University and the winner of the L’Oreal-UNESCO Award for Women in Science — told NPR.
While it may be a while before people are battery-powered, techniques are in development that would allow devices like watches, smartphones and medical implants to draw a charge from surplus human energy using enzymatic biofuel cells, or EFCs. Blood is at the top of the list as a potential energy source. “Plasma, the liquid component of blood, is constantly suffused with dissolved glucose, our cells’ primary source of energy,” according to this article by Ars Technica, which identifies the inner-ear and feet for alt power. Being “so plugged in” takes on a whole new meaning.