Why Is It So Difficult to Sleep While Sitting Up?

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iStock

Many of you traveling home to visit friends and family over the holidays will encounter the eventual need to sleep on an airplane, train, or bus, or in a car … while sitting up. Have you ever wondered why it's so much more difficult to get a good sleep in the upright position as opposed to lying flat in bed?

In order to understand it, you first need a quick primer of your sleep cycles: The human brain cycles through five phases of sleep when your head hits the pillow, the fifth of which is called rapid eye movement (REM) sleep. REM only makes up about 25 percent of your sleep cycle, and occurs approximately 70 to 90 minutes after you fall asleep, but you enter REM sleep several times during the night. During REM, the brain sends signals to the spinal cord to create a temporary paralysis of your muscles, which causes you to lose muscle tone. 

"Usually during REM sleep, other than eye movements, our voluntary muscles are paralyzed," Dr. Neil Kline, an internist and sleep disorder physician and CEO of the American Sleep Association, tells Mental Floss. "We likely evolved this disconnect during REM sleep in order to prevent injury to ourselves." For individuals who suffer from REM sleep behavior disorder (RBD), “this disconnect is faulty," Kline says. "People with RBD act out their dreams, and often injure themselves and others."

The partial paralysis and loss of muscle tone make holding the upright posture of a straight back and neck difficult. It may be why your seatmate tilts sleepily into your personal space, snoring on your shoulder, and why sleeping on a plane is just hard to do comfortably.

Despite this difficulty, some Buddhist monks purposely sleep sitting up as part of their meditation practice for up to five hours per night. They sit in specially designed chairs with hard, firm backs and proper cushioning, and do this as part of a goal to be in meditation as many hours of the day as possible. Your goal may be just an hour of snoozing between takeoff and landing.

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How and Why Did Silent Letters Emerge in English?

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iStock/Bychykhin_Olexandr

Kory Stamper:

The easy answer is “"because English can’t leave well enough alone."

When we first started speaking English around 600 AD, it was totally phonetic: every letter had a sound, and we sounded every letter in a word. But English—and England itself—were influenced quite a bit by the French, who conquered the island in 1066 and held it for a long time. And then later by Dutch and Flemish printers, who were basically the main publishers in England for a solid two centuries, and then by further trading contact with just about every continent on the planet. And while we’re shaking hands and stealing language from every single people-group we meet, different parts of the language started changing at uneven rates.

By the 1400s, English started to lose its phonetic-ness: the way we articulated vowels in words like “loud” changed slowly but dramatically, and that had an effect on the rest of the word. (This is called “The Great Vowel Shift,” and it took place over a few hundred years.) Somewhere in the middle of the GVS, though, English spelling became fixed primarily because of the printing press and the easy distribution/availability of printed materials. In short: we have silent letters because the spelling of words stopped changing to match their pronunciations.

This post originally appeared on Quora. Click here to view.

What’s the Origin of Jack-O’-Lanterns?

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iStock/matejmo

The term "jack-o'-lantern" was first applied to people, not pumpkins. As far back as 1663, the term meant a man with a lantern, or a night watchman. Just a decade or so later, it began to be used to refer to the mysterious lights sometimes seen at night over bogs, swamps, and marshes.

These ghost lights—variously called  jack-o’-lanterns, hinkypunks, hobby lanterns, corpse candles, fairy lights, will-o'-the-wisps, and fool's fire—are created when gases from decomposing plant matter ignite as they come into contact with electricity or heat or as they oxidize. For centuries before this scientific explanation was known, people told stories to explain the mysterious lights. In Ireland, dating as far back as the 1500s, those stories often revolved around a guy named Jack.

LEGEND HAS IT

As the story goes, Stingy Jack—often described as a blacksmith—invited the devil to join him for a drink. Stingy Jack didn't want to pay for the drinks from his own pocket, and convinced the devil to turn himself into a coin that could be used to settle the tab. The devil did so, but Jack skipped out on the bill and kept the devil-coin in his pocket with a silver cross so that the devil couldn’t shift back to his original form. Jack eventually let the devil loose, but made him promise that he wouldn’t seek revenge on Jack, and wouldn’t claim his soul when he died.

Later, Jack irked the devil again by convincing him to climb up a tree to pick some fruit, then carved a cross in the trunk so that the devil couldn’t climb back down (apparently, the devil is a sucker). Jack freed him again, on the condition that the devil once again not take revenge and not claim Jack’s soul.

When Stingy Jack eventually died, God would not allow him into heaven, and the devil, keeping his word, rejected Jack’s soul at the gates of hell. Instead, the devil gave him a single burning coal to light his way and sent him off into the night to “find his own hell.” Jack put the coal into a carved-out turnip and has supposedly been roaming the earth with it ever since. In Ireland, the ghost lights seen in the swamps were said to be Jack’s improvised lantern moving about as his restless soul wandered the countryside. He and the lights were dubbed "Jack of the Lantern," or "Jack O'Lantern."

OLD TALE, NEW TRADITIONS

The legend immigrated to the new world with the Irish, and it collided with another old world tradition and a new world crop. Making vegetable lanterns was a tradition of the British Isles, and carved-out turnips, beets, and potatoes were stuffed with coal, wood embers, or candles as impromptu lanterns to celebrate the fall harvest. As a prank, kids would sometimes wander off the road with a glowing veggie to trick their friends and travelers into thinking they were Stingy Jack or another lost soul. In America, pumpkins were easy enough to come by and good for carving, and got absorbed both into the carved lantern tradition and the associated prank. Over time, kids refined the prank and began carving crude faces into the pumpkins to kick up the fright factor and make the lanterns look like disembodied heads. By the mid-1800s, Stingy Jack’s nickname was applied to the prank pumpkin lanterns that echoed his own lamp, and the pumpkin jack-o’-lantern got its name.

Toward the end of the 19th century, jack-o’-lanterns went from just a trick to a standard seasonal decoration, including at a high-profile 1892 Halloween party hosted by the mayor of Atlanta. In one of the earliest instances of the jack-o’-lantern as Halloween decor, the mayor’s wife had several pumpkins—lit from within and carved with faces—placed around the party, ending Jack O’Lantern’s days of wandering, and beginning his yearly reign over America’s windowsills and front porches.

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