Though we often take it for granted, the human body is amazing. Seriously, I have no idea how doctors manage to examine human bodies all day long without constantly exclaiming, "THIS IS AWESOME." (NB: This is probably why I am not a doctor.) But it becomes particularly wild once you delve into the region of health and illness. The body can go through a lot; you may believe you understand this from TV shows or movies you've seen, but trust me, you've probably only ever scratched the surface of what the body can take. There are a whopping 100 types of cancer in the world, but human beings out there have also survived being hit by lightning seven times, having their heart stop for 78 minutes, and, like Senator Gabrielle Giffords, being shot in the head at close range. We are strange, incredible creatures.
The other interesting thing about the human body, though, is how many myths exist about its remarkable possibilities. In researching this article I came across whoppers that have had their origin in urban myth: that the ability to roll your tongue is genetic (nope), that hair grows back thicker when you shave it (nuh-uh), that cracking knuckles gives you arthritis (no), and so on. Let that be a lesson to you: there are a lot of bunk facts about our bodies floating around out there. Next time somebody tries to impress you with an Awesome Body Fact at a party, demand to see the receipts.
And there's no reason to make stuff up, when the truth is so impressive. All 10 of these facts about your body are totally scientifically proven, which makes them even more amazing. Thank your lucky stars and give your body a pampering for being so utterly awesome without even trying.
1. Weight Gain Creates Thousands Of New Blood Vessels
Whether you put on fat or muscle, when you gain weight, your body has to find ways to make sure that new weight has oxygen — which means that it produces a huge range of new blood vessels to serve the new area. (A common estimate you may see bandied around the Internet is that your body creates seven miles of blood vessels for each new pound of weight, but where this statistic came from is unclear, and fat and muscle have different requirements for blood flow. Again: Don't believe everything you read.)
2. Your Brain Is A Massive Calorie-Guzzler
Calculators that claim to measure calorie intake versus exercise often forget one particular thing about the body's function: when it comes to calories, the brain is a massively greedy organ. No matter how much you eat and drink, the brain will grab the lion's share of the calories in order to function — up to 20 percent of your total intake. That's gigantic.
But Scientific American debunked the idea that a "harder working" brain should burn more calories back in 2012. Your brain demands the same amount of energy from you at all times, whether you're sweating over algebra or giggling at Gilmore Girls returns. Serious mental work tires out your entire body, but energy use in the brain is a tricky thing to pin down, and it doesn't seem like this is a straightforward tie between tough mental work and burning extra calories. Sorry, guys.
3. We Can Survive Without Big Chunks Of Our Organs
How much of your body would you like to live without? The answer is, probably, "none of it" — but it may comfort you to know that, if push came to shove, you probably could survive with only small amounts of those squishy things in your abdomen. Yup, we all have far more organs than we actually need for survival. You probably already know that you can survive on one kidney (hence the ability of people to donate kidneys for transplants), but you can also live without most of your large intestine, all of your stomach, over 50 percent of your liver, and basically all of your bowel. Hell, Pope Francis only has one lung, and he's managing to run around being Pope.
4. The Liver Adapts To Its Host
If you do lose part of your liver, have no fear. It's basically the only bit of the body that can fully regenerate; it's the Wolverine of your organs. This is what makes it pretty great for transplant into new patients, too: it'll adapt to wherever it's put, including fitting into the right size. Remarkably, though, it doesn't always adapt all the way, and sometimes, it will force the new body around it to adapt — a girl who had a liver transplant in 2008 found that her new liver had actually changed her blood type.
Interestingly enough, it's been shown that having Hepatitis C may actually be a good thing if you need a liver transplant, because it suppresses the body's immune system enough to let it adapt to the new organ (otherwise something called "rejection" can happen, which is highly unpleasant and means the immune system is attacking the new arrival).
5. We Can Survive Without Sleep — For A While
Yes, you can actually survive while being kept awake for days — but you'll have a hell of a time. The longest period anybody's ever gone without sleep is 11 days and 24 minutes, a record held by a teenager from California, who did the experiment in 1964. The poor teen was hallucinating and could barely function by the end of it, but he was definitely still alive.
6. Eyebrows Are Designed To Keep Sweat Out Of Our Eyes
Eyebrows actually have a number of evolutionary purposes. One is to give us the possibility of expression, and allow us to communicate with other members of our species. The main reason, however, is pretty crucial to those of us who love to exercise and get sweaty: they're actually designed to keep sweat out of our eyes.
The cultivation of large brows, then, may actually be more than a fashion statement for the Cara Delevingne-conscious folks out there; it might actually make you more comfortable while you're running on the treadmill. (Eyelashes have a similar eye-protecting function: they're designed to keep harmful particles away from the eye surface. That's why camels have such enormously long ones.)
7. A Significant Percentage Of Your Weight Is Bacteria
Bacterial science is an area that's getting a lot of attention this year — partially because scientists are beginning to discover that the bacteria we carry in our gut can have huge implications for our overall health. Luckily for said scientists, they have quite a lot to work with in each human being. That's because the usual amount of bacteria carried around by a health adult human is three to five pounds.
Yes, I am aware that is the size of a small dog. But don't worry: bacteria aren't evil — at least, not all of them. They play a pretty crucial role in how we digest our food, regulate our systems, and within our own bodies, they outnumber our own cells by about ten to one. You have more bacteria in your mouth than there are people on earth: 700 different strains of bacteria have been found living in human mouths, each of which can set up vast colonies.
8. Your Stomach Risks Digesting Itself Every Three Days
The stomach is actually a seriously influential organ. It's not just a food-bag that dissolves everything you eat in acid and then settles down for the night; it's an organ with 100 million neurons in it, which seriously impacts on our emotional state among other things. The real interesting and shocking thing, however, is that the stomach is so powerful, it could do itself in. The stomach must produce a new lining every three to six days, otherwise the acids and enzymes in its liquid will dissolve it.
You've encountered the damage that can be done by digestive juices if you've ever had gastritis, which is an illness where the lining of the stomach gets corroded by its own soup. To prevent this, the body replaces the stomach's mucosal barrier every three days. Shocking, right? It seems quiet, but really, it's all go-go-go down there.
9. Your Body Can (Briefly) Survive In A Total Vacuum
Yes, you can actually survive in a vacuum, so do not believe the space films where peoples' heads explode the second they step outside the craft. It's not true. Their survival in the vacuum of outer space would not be pretty, and would only last for a few minutes, but it is possible. Scientific American pointed out that your body wouldn't explode, because your skin is actually pretty good at keeping your insides in; rather, you'd probably lose consciousness, and eventually die from the lack of oxygen and the air expanding in your lungs.
The Guardian mentions that there was actually, horrifically enough, a practical example of this survival: a 1965 experiment gone horribly wrong, in which a man named Jim LeBlanc, who was testing a suit inside a NASA vacuum chamber, was accidentally exposed when his suit failed. LeBlanc survived, and reports that he felt the saliva on his tongue start to "bubble" before he lost consciousness after around 14 seconds.
10. Your Sweat Can Fingerprint You
Your sweat may actually cause you more problems than you realize — especially if you're on the run from a crime. We all know DNA testing is far more laborious than Law & Order: SVU makes it seem, but it looks like one of the weird things about sweat may actually prove to be a DNA-identifying trap for some future ne'er-do-wells.
Sweat, it seems, acts as a kind of "glue" for cells, meaning that anything you touch when you're sweaty doesn't just leave your fingerprints behind — it'll also likely leave tiny samples of your DNA. This is because sweat is full of bacteria and old skin cells. Which means that fingerprinting may serve double duty as a DNA identifier, provided that the subjects are sweaty enough. Hey, give them enough time with Olivia Benson and they'll be sweating buckets. (What do you MEAN she isn't real?)