Unhealthy Curiosity

This episode explores how drugs, foods, poisons, cosmetics and assorted bodily malfunctions can produce human skin in all 7 colours of the rainbow (and how Isaac Newton is to blame for us thinking a rainbow has 7 colours in the first place).

Dehydration. Too much water. Too much exercise. Not enough exercise. Apparently almost anything can cause a muscle cramp. This episode explores why your muscles occasionally seize without permission, what your nervous system has to do with it, and whether magnesium actually helps.

How can the hunk of meat in your mouth ‘know’ what the food smeared over it tastes like? This episode explores what actually makes something sweet, sour, salty, bitter or umami, and what maggot-infested cheese, antifreeze and a poisoned Roman emperor have to do with it.

Spoiler alert: yes. A nosebleed may have finished off one of history's most feared warlords. This episode explores why noses bleed so dramatically, the ingenious anatomy hidden inside your nostrils, exactly what to do the next time your nose starts gushing... and one of the strangest nosebleed case reports ever published.

Your blood is always red. So why the bruise rainbow? This episode explores the colourful chemistry of bruises, from love bites and cupping to creatures with blue, green and yellow blood - and what Tiffany & Co.'s famous turquoise packaging has to do with it.

This episode explores the history hidden inside your belly button, from Renaissance arguments over whether Adam had a navel, to the doctor who classified sixty different types of belly button, to the German students who deliberately collected facial scars to improve their marriage prospects. Classify your own belly button using Thomas Cullen's 1916 guide.

The marathon wasn't designed by sports scientists. It was shaped by an ancient legend, a royal whim, and one spectacularly bad Olympic experiment involving purposeful dehydration, brandy, and rat poison.

A famous biology textbook diagram. A Harvard psychologist called Edwin Boring. And somehow... netball. This episode explores the mad history of the tongue map, and why taste exists in the first place.

If you thought doing sit-ups would give you a six-pack, think again. This episode explores the gruelling reality of competitive bodybuilding, and how a 19th century circus strongman used a tape measure, Greek statues, and a little mathematics to define the ‘perfect’ physique. (Do you measure up?)

In one experiment, a man who didn't sleep for a week ended up sobbing about an imaginary gorilla. This episode explores what science has uncovered about the effects of sleep deprivation, from hallucinations to frank psychosis – and whether the brain recovers afterwards.

The inventor of Corn Flakes believed cinnamon was morally suspicious and flavour was a threat to virtue. This episode explores the strange story of John Harvey Kellogg, his wellness empire, his obsession with chewing, vibrating chairs for constipation, and why evolution made flavour far too appealing for his crusade to succeed.

In 1980, flight attendants began apparently sweating blood on flights between New York and Florida. The CDC investigated. The explanation was not what anyone expected. Also featuring blue sweat, pink sweat, and the only diagnostic dilemma ever solved by a dermatologist ringing a snack-food manufacturer.

This episode explores the biology of itching. Including NASA’s emergency Velcro patches, exploding lice in World War I trenches, contagious scratching, "amphetamites", mosquito mouth-javelins, and the imaginary insects produced by the human brain itself.

This episode explores what urine can reveal about you — from pregnancy and diabetes to drugs, disease, and genetic disorders. Including ancient Egyptian pregnancy tests, beetroot-induced panic, blue urine pranks, and why IKEA once asked women to wee on their catalogue.

This episode examines the odd biology and even odder rituals surrounding sneezing. Including sunlight sneezes, chocolate sneezes, and why on earth we feel compelled to bless them.

For thousands of years, doctors believed urine revealed the hidden workings of the body. By peering at a patient’s wee, they diagnosed everything from epilepsy to death — sometimes without even meeting the patient. This episode explores the strange history of uroscopy, the rise of the “piss prophets”, and why modern doctors still occasionally ask you for a wee sample today.

If you were feeling sickly 100 years ago, your doctor might have prescribed a loincloth, a bed, and a sun-drenched balcony in the Swiss Alps. No blood tests or scans — your degree of tan would determine your prognosis. From sun worship to sun-gazing to Coco Chanel accidentally making bronzed skin chic, this episode explores the many ways medicine and mankind have misunderstood the sun.

Your DNA can build a body, grow a tumour, or implicate you in a crime. This episode explores what happens when DNA evidence meets identical twins, and why one of Europe’s most feared serial killers turned out to be much stranger than anyone expected.

If you’ve ever heard a recording of your own voice, you may have wished for a voice transplant. But would it be possible? This episode explores why your voice is more than your voice box — and what it would actually take to sound like Elvis.

Your oesophagus was never designed to handle acid splashes — and yet, sometimes it has to. This episode looks at heartburn — why it happens, the neat trick emergency doctors use to distinguish it from a heart attack, and what spaceflight reveals about reflux.