Feet, farts and more body myths!

A new book dispels myths about the human body – and will make your jaw drop!

SO YOU think you know most of what you need to know about your body, do you? You know where all your organs are, you know you’ll kill off your brain cells if you drink too much and if you keep taking your vitamin C every day you’ll ward off a cold.

Right? Well, forget it. In a new book, Everything You Know about the Human Body Is Wrong, science journalist Matt Brown dispels myths you once believed to be true – including the one about farts.

YOUR STOMACH IS DOWN BEHIND YOUR BELLY BUTTON

Actually no: it sits like a champion on top of the rest of the gut. It’s much higher in the abdomen than most of us realise.

Find the point where your lower ribs meet in the middle, then go three finger-widths down and three to your left. You should be right over the centre of your stomach. It’s closer to the nipples than the belly button.

A FLATLINING HEART CAN BE RESTARTED WITH A DEFIBRILLATOR

Prepare to be shocked. A flatlining heart can’t be restarted with an electric charge. This goes against almost every medical drama you’ve ever seen. It also confounds common sense. Surely a heart that’s lost its electrical activity should be zapped back to life with a defibrillator? This would be similar to jumpstarting a car by using an external source of electricity to bypass a flat battery. It would also be wrong. When somebody flatlines it means no electrical activity can be found in the heart. The complex dance of the electrolytes has stopped or dwindled to undetectable levels. Applying an electric shock can do nothing to help. It’s like trying to jumpstart a car that has no fuel.

Electric shocks work only if the heart has some kind of electrical activity – a “shockable rhythm”. The most common scenario is when the heart stops its familiar “lub-dub” and instead goes into a quiver.

The individual cells still pump electrolytes but not in a coordinated fashion – like a sports crowd whose members are all chanting different songs. Shocking a heart with a defibrillator forces all the cells to contract at once, resetting them to the same state. If successful, the heart resumes its regular rhythm.

Applying an electric shock can do nothing to help. It’s like trying to jump-start a car that has no fuel

The appendix’s only role was to make otherwise healthy people scream with pain. Or so people thought

THE APPENDIX HAS NO KNOWN FUNCTION

The poor old appendix has a reputation as a useless organ. The worm-like feature extrudes from the large intestine; a tube that goes nowhere. Even its name, shared with the part of a book that holds surplus information, suggests the inessential.

Its only role is to make otherwise healthy people scream with pain when it decides to go wrong. It can – and often is – removed without any ill effects. This is a pointless organ. Or so people thought. The appendix, it now seems, is a reservoir for helpful bacteria. Microbes that help us fight disease are stored there ready to be deployed if an illness wipes out their brethren in the wider gut. The appendix also plays a part in the body’s immune system. During our early years the appendix helps out with the formation of white blood cells and certain types of antibody.

In the fetus, the appendix produces peptide hormones that feed into homeostasis, the complex series of interactions that keep the body’s internal environment in balance.

SUGAR MAKES CHILDREN HYPERACTIVE

Contrary to just about everyone’s received wisdom, there’s no link between the amount of sugar children eat and their level of excitement. There are many good reasons for not overloading a diet with sugar. Avoiding hyperactivity isn’t among them.

The link, or lack of, has been tested in at least a dozen careful trials. These have looked at sugar in sweets, chocolate, drinks and natural sources. In no study did children on the sugar-free diet behave any differently to their sweetened playfellows.

One study even looked at the effects on parents. Those who thought their children had been given sugary drinks (even when they hadn’t) tended to rate their offspring as more hyperactive than normal. In other words, it’s a self-fulfilling prophecy.

YOU KNOW WHAT THEY SAY ABOUT MEN WITH BIG FEET . . .

The idea that a man with large feet will also possess a substantial penis is hearsay. Somebody did the science.

A 2002 study at University College London found no correlation. For any male readers who want to check their own non-vital statistics, the average “stretched penile length” is 13cm, while the average UK shoe size is nine.

Dead hairs don’t talk. No message is sent back to say, ‘Hey, look, I’ve just been decapitated’

ALCOHOL KILLS BRAIN CELLS

Drinking excessive alcohol is never a good idea. Alcoholics face a higher risk of liver and heart disease, among other ailments. Under the influence you might fall, get into a fight or generally act like a stupid person.

And then there’s the hangover. Despite the risks, many of us are guilty of occasional overindulgence. Are we giving our brains a hammering with all that alcohol?

Common wisdom would have us believe that alcohol is the destroyer of brain cells. Some even claim hangovers are caused by the alcoholic poisoning of neurons. There’s a fermented grain of truth to the notion, but – like a hopeless drunk – it doesn’t fully stand up.

Any alcohol we drink is broken down in the liver. The organ is effective but slow at its task. Most people who drink alcohol do so more quickly than the liver can handle. That’s kind of the point.

The surplus alcohol circulates in the blood and passes through the brain. It doesn’t destroy the brain cells but it does interrupt the signalling between them. This leads to slurred speech, lack of inhibitions, dizziness and all the other wonderful, lamentable and laughable effects we associate with drunkenness.

Just as a bad storm might interfere with your TV signal but won’t damage your television, so a night of moderate drinking will only temporarily affect the brain. That said, heavy drinking, especially over many years, can lead to brain damage by other mechanisms.

The hangover the following day then has nothing to do with the death of brain cells. It’s all about dehydration. The shrewd boozer will take a glass of water after each alcoholic drink to avoid a crushing aftermath.

FINGERNAILS AND HAIR CONTINUE TO GROW AFTER DEATH

If you ever find yourself among the ranks of the undead you might want to track down an accessory stall. The typical movie zombie has long, matted hair that really should be tied back with a band. It just gets in the way of a good mauling. Zombies also sport long fingernails, verging on claws. Both are symptoms of passing over. For when we die our hair and fingernails continue to grow. This well-known piece of hearsay is as mythical as zombies themselves. It isn’t physiologically possible for any tissue to grow after death. Hair and nails are made chiefly of keratin, a tough, fibrous material. For them to grow the constituent cells would need to divide. This can only happen if there’s a supply of raw materials and energy, and that requires oxygenated blood flow. When the heart stops, so too does blood flow. There’s no way the cells can divide. Even so, there are many accounts of exhumed corpses that look hairier than expected. There may be two reasons for this. First, the body dries out in the days following death. Skin contracts and begins to break down. Hairs, and particularly stubble, stand out against the diminished flesh. Second, the keratin that makes up hair and nails takes much longer to break down than other tissue. It’s the most obvious feature on a long-withered corpse.

SHAVING CAUSES HAIRS TO GROW BACK FASTER OR ROUGHER

No matter how close you shave you won’t be touching living tissue. The part of each hair that’s alive and growing, called the follicle, is subcutaneous – that is, within the layers of skin. When a razor slices the hair close to the skin it’s cleaving a path between cells that are no longer alive.

Dead hairs don’t talk. No message is sent back to the hair root to say, ‘Hey, look, I’ve just been decapitated.’ As far as the follicle is concerned, you might have chopped off the whole visible hair, just the tip or nothing at all. Consequently, there’s no difference in the quality of hair that eventually grows back. Nor does it shoot out with extra speed.

Where does this shaggy-dog story come from, then? It seems to fit with our experiences. Stubble on our chins or legs feels much coarser than locks that have been allowed to grow. This is simply because the hair closer to the root is a little bit thicker than hair that’s grown out. It’s no coarser than it was before the shave but the removal of the tapered ends makes it seem so.

Stubble is also a bit darker than hair that’s grown long. Light exposure and chemical pollutants can cause bleaching – the longer the hair’s been exposed, the greater the degree.

Someone who goes from flowing coiffure to crew cut will be left with only the darker sections of hair, which can add to the impression of coarseness.

Waxing hair does get to the root. The entire hair is yanked clean out, along with dozens of neighbours. This is painful (I’m told) but leaves the skin clear of hair for several weeks.

When it does grow back, the hair is usually of the same thickness as previously. Multiple waxings can lead to finer hair, as root structures become damaged. It certainly won’t make the hair grow back thicker or coarser.

SOME PEOPLE JUST DON’T FART

The queen farts. It’s true. Few will ever witness the august bottom burp, but Her Majesty must parp at least a dozen times a day.

All humans do. There’s no avoiding it. Most of the noisome gas is created as a by-product when bacteria in the gut break down food. The rest comes from swallowed air or perhaps carbon dioxide from fizzy drinks.

Speaking of which, a typical daily gas yield would fill a two-litre cola bottle – an experiment most schoolboys will have contemplated at some point.

No human (or other creature with a gut) is exempt. We all produce bubbles of gas. You can try to hold them in, and you might think you’ve succeeded, but the vapours will escape sooner or later. The unspeakable gas may sneak out slowly and stealthily – or might issue forth with an uncontainable pop.

But farts don’t get reabsorbed or go away.

Not all farts are obvious, though, even to the dealer. The main emissions are methane, hydrogen, nitrogen and carbon dioxide, all of which are odourless. That distinctive smell comes from hydrogen sulphide and other sulphurous compounds, which make up just 1% of a typical emission. If you’ve not recently eaten sulphur-heavy foods, your exhaust may be almost odourless.

YOU’LL CATCH A COLD IF YOU GO OUT IN THE RAIN

Call it Jane Austen syndrome or the Dickensian flu: the tragic lover caught in a shower is a familiar cliché of the classic novel. Soaked to the skin, they’ll either be bedridden for the next 12 chapters or die from the chill.

It might be a melodramatic way of moving the plot forward but the idea of a lengthy illness caused by a drenching is exaggerated. Colds and flu are viral infections. You need to be exposed to someone or something with the virus before you’ll catch it yourself. Raindrops don’t carry the virus. Nor do chilly winds. You can’t catch the flu by being wet or being cold, or going outside with wet hair or running through a rainstorm following an awkward tryst. There is a “however” here, which allows the myth to claw back credibility. Frigid temperatures can’t in themselves give you a cold, but they could hasten its onset if you already harbour the virus. Exposure to cold causes the blood vessels in our extremities to contract. This restricts blood flow to areas affected, which may include the nose and throat. This means fewer immune cells can reach those areas. Cold exposure, then, could reduce the efficiency of an immune response to a virus that’s already in our airways. The evidence remains inconclusive but it’s a persuasive idea. Another factor is that cold or wet weather tends to keep us indoors for longer periods. The warm, confined conditions close to other people and the germs they carry, are perfect for transmitting the virus.