Why Do Limbs 'Fall Asleep'?

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iStock

At some point, we've all experienced the sensation of "pins and needles"—that strange numbness that comes from applying pressure to our arms or legs. If you've ever wondered what causes it, or if it's dangerous, wonder no more.

We've got nerves running through our bodies that act as lines of communication between the brain and the other body parts, transmitting commands from the brain and relaying sensory information back to it for processing. With a "sleeping" limb, your nerves are going a little haywire because prolonged pressure has actually cut off communication between that limb and the brain. (The tingling sensation is technically called paresthesia.)

Pressure puts the squeeze on nerve pathways and blood vessels, so the nerves can't transmit signals properly, and the blood vessels can't bring oxygen and nutrients to the nerves. The cutoff interferes with the normal flow of information between the limb and the brain, and the signals going back and forth get jumbled. Some nerve cells stop sending info entirely, while others send impulses erratically.

The problem is compounded by the fact that our nerves are pretty specialized, and different kinds of nerves and sensory receptors receive different stimuli and transmit different information. (We've discussed another bodily oddity caused by this.) When the various signals get scrambled and aren't transmitted normally, the brain starts to misinterpret the info it's getting and generates an array of sensations, like warmth, numbness, and that tingling feeling.

When a limb falls asleep, we usually try to "wake it up" by changing positions. Blood flows back to the limb, giving a little boost to the misfiring nerves and making the tingling seem worse, but eventually the nerve signals begin to flow properly again. The pins-and-needles sensation is annoying for a few minutes, but it's a nice little prompt for us to relieve the pressure on a limb before serious nerve damage occurs.

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Why Does Santa Claus Give Coal to Bad Kids?

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iStock/bonchan

The tradition of giving misbehaving children lumps of fossil fuel predates the Santa we know, and is also associated with St. Nicholas, Sinterklaas, and Italy’s La Befana. Though there doesn't seem to be one specific legend or history about any of these figures that gives a concrete reason for doling out coal specifically, the common thread between all of them seems to be convenience.

Santa and La Befana both get into people’s homes via the fireplace chimney and leave gifts in stockings hung from the mantel. Sinterklaas’s controversial assistant, Black Pete, also comes down the chimney and places gifts in shoes left out near the fireplace. St. Nick used to come in the window, and then switched to the chimney when they became common in Europe. Like Sinterklaas, his presents are traditionally slipped into shoes sitting by the fire.

So, let’s step into the speculation zone: All of these characters are tied to the fireplace. When filling the stockings or the shoes, the holiday gift givers sometimes run into a kid who doesn’t deserve a present. So to send a message and encourage better behavior next year, they leave something less desirable than the usual toys, money, or candy—and the fireplace would seem to make an easy and obvious source of non-presents. All the individual would need to do is reach down into the fireplace and grab a lump of coal. (While many people think of fireplaces burning wood logs, coal-fired ones were very common during the 19th and early 20th centuries, which is when the American Santa mythos was being established.)

That said, with the exception of Santa, none of these characters limits himself to coal when it comes to bad kids. They’ve also been said to leave bundles of twigs, bags of salt, garlic, and onions, which suggests that they’re less reluctant than Santa to haul their bad kid gifts around all night in addition to the good presents.

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Why Are Poinsettias Associated with Christmas?

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iStock

Certain Christmas traditions never seem to go out of style. Along with wreaths, gingerbread cookies, and reruns of A Christmas Story sits the poinsettia, a red-tinged leafy arrangement that’s become synonymous with the holiday. Upwards of 100 million of them are sold in the six weeks before December 25.

Why do people associate the potted plant with seasonal cheer? Chalk it up to some brilliant marketing.

In 1900, a German immigrant named Albert Ecke was planning to move his family to Fiji. Along the way, they became enamored of the beautiful sights found in Los Angeles—specifically, the wild-growing poinsettia, which was named after Joel Roberts Poinsett, the U.S.-Mexican ambassador who first brought it to the States in 1828. Ecke saw the appeal of the plant’s bright red leaves that blossomed in winter (it’s not actually a flower, despite the common assumption) and began marketing it from roadside stands to local growers as "the Christmas plant."

The response was so strong that poinsettias became the Ecke family business, with their crop making up more than 90 percent of all poinsettias sold throughout most of the 20th century: Ecke, his son Paul, and Paul’s son, Paul Jr., offered a unique single-stem arrangement that stood up to shipping, which their competitors couldn’t duplicate. When Paul III took over the business in the 1960s, he began sending arrangements to television networks for use during their holiday specials. In a priceless bit of advertising, stars like Ronald Reagan, Dinah Shore, and Bob Hope were sharing screen time with the plant, leading millions of Americans to associate it with the holiday.

While the Ecke single-stem secret was eventually cracked by other florists—it involved grafting two stems to make one—and their market share dwindled, their innovative marketing ensured that the poinsettia would forever be linked to Christmas.

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