Health
Discover facts about health. Small discoveries that change the way you see familiar things.
Health
Eccrine sweat is just pure unadulterated fluid moisture
Eccrine glands release a mostly scentless fluid onto your skin. As that moisture evaporates, it carries heat away, helping cool you down; the cooling comes…
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Your body generates a tiny magnetic field
As electrical signals travel through the nervous system, their currents generate a faint magnetic field around the body. Your nerves are not magnetic organs;…
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A newborn's clearest world is close enough to hold
Early vision works best at roughly eight to twelve inches, about the distance to a face during feeding. Fine detail and color discrimination develop with…
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Why female cells can use different X chromosomes
Cells with two X chromosomes usually silence most of one X in each cell. Because different cells can silence different copies, the body becomes a genetic…
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Elizabeth I's flushing toilet still left someone with a dirty job
John Harington described his water-flushing design in 1596 and supplied one to the queen. A cistern could wash waste out of sight, but it went into a pit that…
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Pilates made springs into adjustable exercise resistance
The reformer's moving carriage works against springs, giving a controlled resistance as the user pushes or pulls. Changing the spring setup changes the…
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Tonsils sit right at the frontline of throat defense
Tonsils sit near the back of the throat, where material entering through the mouth and nose passes by. Immune cells there can encounter germs early, giving…
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Fast twitch muscles tire out almost immediately under load
Fast-twitch muscle fibers provide quick power for a sprint or heavy lift, drawing on small stores of immediately available energy. Those stores run low within…
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Levator labii superioris alaeque nasi
That long-named muscle lifts your upper lip and helps flare your nostrils. When a bad smell makes your nose wrinkle, this small facial muscle is part of the…
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Why human lungs can float
Alveoli—the lungs’ millions of tiny air sacs—can trap air, making lung tissue buoyant. That air is why lungs can float even after death.
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Even chewing has an energy bill
Moving the jaw takes muscular work, so chewing gum raises energy expenditure a little. The harder and longer the jaw works, the more energy it uses. It is a…
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First commercial deodorant officially rolled out in 1888
In 1888, the first commercial deodorant arrived as a zinc-based cream called Mum. Users rubbed it into their armpits—a very hands-on beginning for a product…
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Flotation tanks charge a premium to float in total darkness
The tank’s dense salt water supports your body, so you can float with little effort while the enclosed space blocks light and sound. With fewer outside…
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Some soft bread uses hair-derived ingredients
Some commercial dough conditioners use L-cysteine, which can be extracted from human hair or duck feathers; it helps weaken gluten and soften factory-made…
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Your stomach has a strict bouncer at the exit
The pyloric sphincter is a ring of muscle between your stomach and small intestine. It opens to let small amounts of digested food through, then closes…
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You have a dominant eye and a dominant ear
Your brain may favor one eye when lining up a target and one ear when trying to catch a quiet sound. Those are different jobs, so the preferred sides don’t…
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Measles can linger in an empty room for hours
A person with measles can leave infectious particles suspended in the air. Because they can linger for up to two hours after that person leaves, the room’s…
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An egg's cholesterol is not a direct deposit into your arteries
The body regulates its own cholesterol production, and blood cholesterol responds to the broader diet, including saturated fat. That makes the number in one…
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Older fathers tend to pass on more new DNA mutations
The cell lineage producing sperm keeps copying its DNA through adulthood, giving copying errors more opportunities to accumulate. Children therefore tend to…
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Brown eggs aren't more nutritious
The hen’s genes determine whether the shell comes out brown or white; that color doesn’t tell you how nutritious the egg is. The shell’s paint job and the…
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Why belly-button lint is usually made of shirt fibers
Tiny hairs around the navel point in a direction that catches and nudges shirt fibers inward. They act like a one-way ratchet, so lint gathers in your belly…
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Men produce millions of reproductive swimmers daily
Sperm production runs continuously, generating millions a day. But only a tiny fraction ever reach an egg, and fertilization generally involves just one—so…
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A baby's first poop is odorless tar
Before birth, a baby swallows amniotic fluid along with shed cells and other debris. That material collects in the gut as meconium, a thick, dark stool with…
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Tooth enamel is hard, but it cannot rebuild itself
The cells that make enamel disappear after the tooth develops. Minerals can strengthen an early weakened surface, but a lost chunk does not regrow like skin.…
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