Warning: Yellow journalism alert.

When grown men and little boys urinate, occasionally our entire body is abruptly racked with a mysterious, internal blast of cold that makes us visibly shudder from the shoulders down. It typically occurs near the end of the task, lasting roughly one frigid second.

This chill is not discussed, of course, in polite circles -- or even when we return to our buds in the sports bar. So, at no time will you hear: “Dudes, you’ll never guess what just happened to me in the bathroom?” Well … hopefully never.

Yet, we’ve given this sensation a name: the pee shiver. And as the name suggests, depending on a guy’s aim, it can make for messy results. 

So let’s get right to question No. 1.

Why, in the name of Wiz Khalifa (or, if you like, P. Diddy), does this happen?

No leaks were required to obtain this information. We simply turned to Dr. Anish Sheth, author of “What’s My Pee Telling Me?”

“No one knows for certain what the specific trigger for the shivering is,” says Sheth, formerly director of the gastrointestinal motility program at Yale Medical School. But he points to two generally accepted variables to help solve this riddle.

First, the feeling “mostly” is experienced by males. Second, it “occurs most commonly while voiding large amounts of urine,” he says.

Or, to put it as delicately as possible, the icy jolt seems to hit after we’ve really, really had to go. Never after a tiny trickle.

According to Sheth, our parasympathetic nervous system (responsible for “rest-and-digest” functions) lowers the body’s blood pressure “to initiate urination.” One leading theory behind the shudder is that peeing can unleash a reactive response from the body’s sympathetic nervous system (which handles “fight or flight” actions).

On the cellular level, the body is theoretically flushed with catecholamines (which you know better as chemicals like dopamine or hormones like adrenaline). Those are dispatched to help restore or maintain blood pressure, Sheth says. But the microscopic energy bullets “may also trigger the shiver reflect.”

This theory, the author says, best explains “the gender difference as men pee standing up and, therefore, would be more prone to feeling the effects of a lower blood pressure, thereby triggering this exaggerated sympathetic nervous system response.

“Anecdotally,” he adds, “I don’t believe I have ever experienced the post-pee shivers while sitting down.” This would suggest that women don't tend to get them. (Do you? If so, please let us know.)

“I wouldn't know if it's a guy thing or a girl thing because I've never had a conversation with a girl about this – and it's not likely to happen anytime soon,” says stand-up comedian Dan Nainan

“I always wonder: what is that? … Why is it happening?” Nainan adds. “Obviously there is an evolutionary or natural-selection reason for everything. (But) as I'm trying to picture a caveman urinating out in the open, I'm wondering what the necessity of the shivering is.

“I think it tends to happen more in a public bathroom,” he adds. “Could it be some sort of way to warn off nearby enemies or something?”

Wow, comics must have to endure some pretty rough bathrooms.

Bill Briggs is a frequent contributor to msnbc.com and author of “The Third Miracle.”

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• Why is cracking my knuckles so addictive?
• Can eating too much spicy food kill you?

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The fight begins.

Round One: Your field of vision -- maybe a laptop screen, maybe a TV screen -- slowly dissolves from bright and wide to dim and squinty. Your eyelids are drooping.

Round Two: Soft, steady blinks set in, like a referee counting you out. Your lids feel like slabs of cement. In a desperate push, you forcibly ram your bulbs open: a brief, final glare at the fading world.

Round Three: Your brave gaze promptly melts into a haze of lashes. The cement-laden lids now feel like they’re also carrying cement mixers.

 Round Four: You’re out.

That nightly bout -- you versus Morpheus (or, if you’re not into Greek mythology, you versus the Sandman) -- is a simply the last moment of a war of attrition inside the muscles that power your eyelids, including the levator, the Mullers, and the frontalis. Those tiny fibers feel heavy after a day of watching, scanning, looking and gawking. It’s just a matter of muscle fatigue, no different than your biceps feeling spent after a set of curls in the gym.

“Reading – or, like I’ve been doing the past few days, working on the computer – really wears those muscles down like your legs would become tired from walking for a whole day,” says professor Mark A. W. Andrews, professor of physiology at Seton Hill University in Greensburg, Pa. (Before a phone interview with The Body Odd, Andrews had spent three straight days preparing exams for his students).

Your lids can feel extra hefty after days “when you have to concentrate and keep them open a certain amount, “Andrews adds. “It’s even worse when you’re working in a darker environment. Just like an f-stop on a camera (which regulates exposure), you have to make sure your eyes are fully widened, letting all the possible light in.”

This also explains your instinctive attempt to momentarily revive tired eyes -- gently rubbing them with your fingers.

“What feels good after you exercise certain muscles? A massage of sorts,” Andrews says. “That rubbing is going to increase the blood flow in the area and get rid of waste materials that are generated from fatigue. The rubbing washes the waste materials out and into the lymph system.”

What’s more, this is why tired eyes tend to look puffy, he adds: “When you’re using a muscle a lot, there’s a lot of vascular pressure, a lot of blood flowing through.”

In people with anatomically heavier eyelids, Andrews explains, their lid muscles can fatigue even faster than in people with thin lids. Sorry about that, Blake Lively. 

And as we age, many of us acquire “fat pads,” beneath our eyes. This extra tissue makes the heavy-lid sensation “more prevalent” when we're weary, Andrews says. Even worse, at that stage look just as tired as we feel.

Anyway, all this chatter about sleepy eyes is making my eyelidzzzzzzzzzzzzzzzzzzzzzzzzz … Oh no. Round One.

Bill Briggs is a frequent contributor to msnbc.com and author of “The Third Miracle.”

Related:

• How do blind people dream?
• Why is cracking my knuckles so addictive?
• Wait, haven't I read this before? The science of deja vu

Want more weird health news? Find The Body Odd on Facebook.

We ask a lot of weird questions here at The Body Odd. But so do you! Here's our answer to one of your latest queries. Got an inquiring mind? Head over to our Facebook page and ask us your oddest health, medical or human behavior question. We may answer it in an upcoming post.

Today's question: Why is cracking my knuckles so addictive?

The pop! pop! pop! of each cracked knuckle is so sweetly satisfying to you. But it's slowly driving everyone around you completely nuts. You don't remember when you started it, but you can't seem to make yourself stop. Why? "There’s not any hard science to explain why it’s so addictive, but certainly people speculate it’s one of these activities that releases nervous energy," says Dr. Rachel Vreeman, assistant professor of pediatrics at Indiana University School of Medicine and co-author of "Don't Cross Your Eyes ... They'll Get Stuck That Way!"

Some people twirl their hair, some people jiggle their foot up and down -- and some people pop their knuckles. "Many people who do it believe that it feels good," Vreeman says. "They find it to feel good or comfortable, or it even gives them some physical release."

We should note that when you "crack" your knuckles -- you're not actually cracking anything. "That sound you hear is synovial fluid vapor cavities -- or gas bubbles -- in the fluid around your joints. With certain amounts of pressure you can make those bubbles burst." She's making it sound like popping bubble wrap -- no wonder both activities are equally satisfying. 

And, no, cracking your knuckles won't give you arthritis, despite wild rumors you may read on the Internet. Vreeman says in studies of hand function in adults both with and without arthritis, those with arthritis weren't any likelier to be knuckle-crackers. In other words, she says "It doesn’t seem like you’re likely to get arthritis because of your annoying knuckle cracking."

Still, habitual knuckle-popping might lead to some hand discomfort, including swelling, reduced hand strength and even some finger or joint injuries. So, how do you knock it off? 

"Certain things that make you more likely to break your bad habit: coming up with a clear plan. Having some accountability. Telling other people about it," Vreeman says. "From weight loss literature we find that people do better with modifying their eating habits by keeping records -- so keep some record throughout the day how many times a day you did it.

"We also know from sort of the science of habits that it takes ... 28 days to form a habit," Vreeman explains, "so to form an opposite habit probably takes at least that long."

Is there a bad habit you're trying to break in 2012? Let us know how it's going on our Facebook page.

Want more weird health news? Find The Body Odd on Facebook.

Manish Swarup / AP file

"Ghost chili" peppers, pictured here at Changpool in the northeastern Indian state of Assam, were recently named the spiciest chili in the world by Guinness World Records

By Katharine Gammon
Life's Little Mysteries 

In a contest that matches humans against some of the world's hottest chili peppers, no one wins. Recently, restaurant in Edinburgh, Scotland, held a competition to eat the extra-hot Kismot Killer curry. Some of the competitive eaters were left writhing on the floor in agony, vomiting and fainting.

According to reports, two British Red Cross workers overseeing the event at the Kismot Indian restaurant in Edinburgh but became overwhelmed by the number of casualties and ambulances were called. Half of the 20 people who took part in the challenge dropped out after witnessing the first diners vomiting, collapsing, sweating and panting.

So what exactly are the health impacts of eating really hot chili peppers? Can eating too much of the spicy stuff kill you?

To answer this question, Life's Little Mysteries turned to one of the experts: Paul Bosland, professor of horticulture at New Mexico State University and director of the Chile Pepper Institute, was responsible for finding the world's hottest chili pepper, the Bhut Jolokia.

Bosland says that chili peppers (or as some call them, chile peppers) can indeed cause death — but most  people's bodies would falter long before they reached that point. "Theoretically, one could eat enough really hot chiles to kill you," he says. "A research study in 1980 calculated that three pounds of extreme chilies in powder form — of something like the Bhut Jolokia — eaten all at once could kill a 150-pound person."

This scenario wouldn't likely have a chance to play out. "However, one's body would react sooner and not allow it to happen," Bosland said. "One would have to eat it all in one sitting," he says. Taken over the course of a year, those three pounds of chilies wouldn't be harmful.

Chili peppers cause the eater's insides to rev up, which can come with some problems. They activate sympathetic nervous system — which helps control most of the body's internal organs — to expend more energy, so the body burns more calories when the same food is eaten with chili peppers. "Eating chili is associated with increases in metabolic rate and thermogenesis," says John Prescott, a professor at Sussex University and editor of the journal Food Quality and Preference. "Capsaicin, the active ingredient in chili, does cause tissue inflammation so the mucosa of the stomach or intestines might be damaged by a sufficiently large dose."

Tissue inflammation could explain why the contestants in the Killer Curry contest said they felt like chainsaws were ripping through their insides. Too much of the spicy stuff can also give you a good case of heartburn.

When it comes to spicy, enough of the hot stuff can cause damage — so eat carefully out there!

Related:

• 10 Weird Things People Do Every Day (and Why)
• Is It Safe to Hold in a Sneeze?
• Why Does Your Nose Run When You Eat Spicy Food?

Want more weird health news? Find The Body Odd on Facebook.

Whether you're a dude in sweat socks and sneakers or a lady in dainty ballet flats, once you take those shoes off -- ew. The whole room can smell your Kimmy Gibbler-style stinky feet. On this morning's TODAY, Women's Health magazine contributor Dr. Keri Peterson answered viewers' most embarrassing health questions -- including how to pretty up those foul feet.

"Smelly feet are from bacteria that thrive when your feet sweat," Peterson explains to Savannah Guthrie. "So the goal to get rid of it is either to decrease the sweat or decrease the bacteria."

To decrease bacteria, wash your feet with anti-bacterial soap, and try applying baking soda inthe shoe or sock. To decrease sweat, wear socks that have breathable material -- for instance, cotton instead of nylon. Wear shoes that are well-ventilated, and give each pair some time to dry out before you jam your feet back in there again. You could even try applying an antiperspirant -- yep, like the one for your underarms -- to the soles of your feet.

Got an embarrassing health question you're too sheepish to ask? Submit it here, and Peterson may answer your query on an upcoming TODAY segment.

Want more weird health news? Find The Body Odd on Facebook.

We ask a lot of weird questions here at The Body Odd. But so do you! Here's our answer to one of your latest queries. Got an inquiring mind? Head over to our Facebook page and ask us your oddest health, medical or human behavior question. We may answer it in an upcoming post.

Becky Coombs asks: Why/how does deja vu happen?

Maybe it's a short circuit in the brain. Or bit of far-off memory slipping into the present. Or perhaps it's both those things and something more.

Whatever the case, deja vu isn't just a strange but irrelevant fact of life (like, say, Snooki).  Better understanding of deja vu will almost certainly lead to better understanding of how our brains work.

So what is deja vu in the first place? "It's the feeling that you have done this exact same thing before -- been to this place or performed this particular activity -- when you know that you haven't," says Colorado State University's Anne M. Cleary, a leading deja vu specialist. "Not everybody experiences it, but the majority of people do."

Young people, from the teenage years through the mid-20s,  experience deja vu the most, says Akira O'Connor, who studies deja vu at the University of St. Andrews in Scotland. Tired people also get it more often, as do those who travel a lot. Even though they have many more years stored in their memory banks, older people aren't as prone to deja vu.

When most of us feel deja vu, we think it's a little odd or even meaningful -- maybe a past life is coming through! -- and go on with our day. Others aren't so fortunate. Some people suffer from deja vecu, a feeling of having already lived.

"It sounds kooky and fun, like a 'Groundhog Day'-type experience, but in reality it's extremely unsettling and drastically changes people's behavior," O'Connor says. "People find that they experience it most strongly for novel experiences. As they find the experience unsettling, they tend to avoid novelty altogether, with the sad consequence that they can withdraw into a world of true familiarity, watching reruns of movies and TV shows over and over again because that brings them the least distress."

There's no good treatment for people with this condition, which is often related to the memory problems of aging. No wonder: there's no clear understanding of what causes deja vu and related feelings in the first place. 

Colorado State University's Cleary said some possible causes of deja vu include errors in the way the brain processes the world around us or "a brief neurological dysfunction, such as spontaneous brain activity that triggers an inappropriate sense of familiarity, or a brief minor seizure." It's possible that multiple causes are at work.

For now, researchers are finding new ways to analyze deja vu. Cleary is using virtual reality to see if they can trigger it in people and figure out exactly what in a "scene" makes it happen. (Vision isn't necessary, though. Blind people have deja vu too.)

"Researchers need to figure out what causes the disconnect between feeling that something is familiar, and knowing that it can't be," Scotland's O'Connor says. "I hope that in my lifetime we figure what parts of the brain are associated with 'feeling' familiarity and what parts are associated with 'knowing' that something should or should not evoke memories."

Just remember this: Maybe it's a short circuit in the brain. Or bit of memory slipping into the present. Or perhaps it's both those things and something more. (No, you're not having deja vu. You already read that. Or did you?)

Leave a comment telling us about the weirdest or most memorable time you experienced deja vu. We may use your answer in an upcoming post.

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We're sure you never drool in your sleep. But if your ... friend ... ever does, Women's Health magazine contributor Dr. Keri Peterson has some helpful advice. Peterson, a board-certified internist, appeared on TODAY this morning to tell us some reasons why this might be happening, and what you can do to knock it off.

"When you sleep, your muscles relax, your mouth falls open, and if you're lying on your side, it's gonna leak out," explains Peterson, adding this fun fact: We make a liter of saliva a day.

"Also, if you have sinus problems, or allergies, and you tend to mouth-breathe, you're gonna be more likely to have this happen to you," she continues.

To keep yourself from drooling all over your pillow -- try sleeping on your back, Peterson advises. Watch the video for more on this, plus answers to more embarrassing health questions.

Got an embarrassing health question of your own? Ask us in a comment -- a writer for The Body Odd may answer it in an upcoming post.

Follow msnbc.com health writer on Twitter: @melissadahl.

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It's Friday, which means two things: We all have that Rebecca Black song in our heads, and it's time for us to answer a reader question. Today, we're tackling a beauty query from our Facebook pal Suzanne Pyles:

But we think this question brings up another question: Why do overplucked hairs stop growing back, anyway?

"Overplucking of the brows can lead to a diminution in the size of the hair follicle, thereby making the new growing hairs smaller and finer as well. This happens when people wax a lot," explains Dr. Carolyn Jacob, a Chicago dermatologist. "Older women tend to lose eyebrow hairs, too, so you don't want to make your brows thin when you are younger. It doesn't look right, and you wont have much, if anything, to work with when you're older."

Onto the real question here: Can the eyebrow hairs you accidentally made disappear ever grow back?

"Sometimes, if the plucking is too forceful or if there is chronic irritation or inflammation, this can lead to damage or scarring of the hair follicle, thus a new hair does not grow," says Dr. Paradi Mirmirani, a dermatologist practicing in Vallejo, Calif. "This is a rare occurence, but once the follicle is damaged it is permanent.  There is no treatment other than hair transplantation that would lead to successful regrowth of another hair shaft."

Short of hair transplantation, you could always consider permanent makeup, although we hear that doesn't always work out so well.

Got a weird health question you're itching for us to answer? Ask away -- leave a comment here, or find us on Facebook or Twitter.

Follow health editor Melissa Dahl on Twitter: @melissadahl.

Want more weird health news? Find The Body Odd on Facebook.

Last week, we outsourced part of our job to our Facebook fans, letting you guys ask the odd health questions this time. This week, we investigated the answers to some of our favorite wonderfully weird queries -- on deja vu, seemingly random memories, hiccups and sneezes. Here's what we found. 

The answer: First of all -- it's not just you. "In recent community studies, approximately 70 percent of the individuals reported some déjà vu experiences," explains Dr. Orly Avitzur, a New York state neurologist. On average, it happens about once a year in healthy individuals -- but it appears to be more frequent when we're tired or stressed. But it can also be pathological, often seen in patients with epilepsy. 

"The temporal lobe, particularly the region of the hippocampus, has been linked to this phenomenon," Avitzur says. "Neurons there store new experiences in a 'mental map' and some scientists have theorized that when very similar events overlap, déjà vu occurs."

Hmm. We feel like we've heard that explanation before.

The answer: We gave this one to Avitzur to tackle, too. "Detailed memories for episodes from our past can be triggered when we’re suddenly exposed to a stimulus that was present during the original event," she explains. "When you’re working at your desk and you experience a memory of a place or person from your past, you may not be consciously aware that an auditory stimulus (like music), or visual stimulus from your computer screen sparked the memory."

But these associations your brain is making might be so subtle that they appear "random" to you. Here's what's happening inside your brain: "Results from functional MRI studies and neuropsychological testing suggest that the prefrontal cortex area of the brain is responsible for episodic retrieval of memories," Avitzur says.

You know, that reminds me of something ... 

The answer: We asked Dr. Peter Abramson, an ear, nose and throat doctor from Atlanta to explain why some of us seem to be more hiccups-prone than others. "Hiccups, essentially, can be caused by a number of different things -- it could be anything from a (gastro-intestinal) issue from having an over-distended stomach to having irritation of the nerves that control the diaphragm," he explains.

People who often get the hiccups may have unusually sensitive nerves that control the diaphragm, Abramson says. Another theory: If you eat too much, and your stomach is often distended, that can trigger the hiccups. A brain tumor is another scary, but unlikely, potential cause of frequent hiccups. 

The answer: We picked Abramson's brain again for this one. Some sneezes are initiated by sensory nerves in the nose, and pressing on the upper lip may help distract those nerves, he explains. "What it may do is decrese the brain’s ability to sense that there’s an irritant in the nose and decrease their chance of having another (sneeze)," Abramson says. 

Got any more weird wonderings about the human body? Ask away -- either here, on our Facebook page, or ask us on Twitter (@bodyodd) with the hashtag #inquiringminds. (And, hey -- keep it SFW, please.) We'll be back next Friday with more answers to your questions.

Follow Melissa Dahl on Twitter: @melissadahl

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