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“Made Me Question What It Even Means To Be Human”: 59 Human Body Facts That Keep People Awake
Your body is with you 24/7. But how often do you actually stop to think about what it’s doing? Probably not much, and honestly, that’s for the best. Because the more you dig into how it really works, the weirder things get.
One Redditor asked users to share the scariest facts they’ve discovered about the human body, and people delivered with some genuinely unsettling answers. If you’re curious, scroll down to see what they shared. There’s a good chance you’ll learn something new—you just might wish you hadn’t.
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#1
As an RN, I can say that personally the scariest thing is modern medicine keeping me alive long after my body should be gone, just because they can “fix it”. I fully believe that we have moved the goalposts on quality of life for it, and I hope if I can’t advocate for myself when the time is right that someone who loves me will.
echinoderm0:
Advance Directives are SO important for this reason. Some states have more specific forms than others, but you can use templates from other states or just create your own and still have a legally binding advanced directive.
RELATED:
#2
The fact that the human body can just randomly develop so many incurable, life-altering, disabling, and even fatal diseases that currently have no identified cause. One random gene mutation, exposure to a certain pollutants or toxin, residual infections from common colds, there's so many things that can basically just cause your body to start relentlessly attacking itself. You could do everything right your entire life, exercise regularly, eat a clean, healthy diet, don't drink, don't smoke, you could do everything right in every way, and just accidentally become exposed to something in your environment that you have some kind of genetic sensitivity towards and boom. It will cause a chain reaction in your body that destroys your motor neurons and your nervous system leading to full body paralysis, respiratory failure, and eventually the end. That's what happens if you get something like ALS. There's no known cause. There's no cure, no way to prevent it. It's pure chance. And once you get it, you've got about 5 years maximum before it ends you. But before it does that, it will take away literally all of your bodily functions first.
SnooRobots7776:
I have heard of an overwhelming amount of cases of COVID turning into horrible problems down the road even if it didn't appear immediately after. I might actually be an example of it as well because the first time that I had COVID was almost 2 years ago, and I ended up developing POTS as well as some other issues that are in-progress to a diagnosis. Pretty insane that something like a type of illness that some had no problems with and even call a hoax now, can have such lingering and terrible effects for others.
#3
Pregnancy has always been scary to me!
We’re all going to pretend it’s normal to have another human growing in another human?
Long-Amount-5436:
LOL. I thought I was a terrible person when pregnant that I didn’t find it magical. It kinda weirded me out. My daughter was loved and wanted and I was a good (enough) mom, but yeah, that pregnancy thing was weird whenever I felt the squirmy movements.
#4
A child's jaw is literally 'filled' with teeth: both baby and permanent teeth are there at the same time, hidden under the gums. If you imagine this visually, it looks quite creepy.
#5
Sudden aneurysms are pretty scary.
PapaTua:
My sister passed away this way right in front of me.
She had a mild headache all day, then a sharper pain for about 30 seconds, and then gone.
I'll be the same age she was when she passed in a year or two. I hope to go the same way at the same age.
Luke || Kira (he/she) 2 hours ago
Happened to my mom's coworker (retail). Someone wanted to access the office with a computer. It was blocked from the other side, by the woman's dead body. Alive one moment, gone the next. Freaky stuff.
#6
That, as amazing as the human brain is, it's seriously flawed and basically constantly hallucinating and making up data based on your past experience. You literally can't trust it to tell you the truth.
kupuwhakawhiti:
This take bothers me. A lot of what we consider bugs in the brain are actually features.
For example, a woman once lost the ability to forget. Sounds like a superpower. But decades after the passing of her husband she was unable to stop mourning him because her memory of the event was as strong after 20 years as the day it happened.
#7
'Locked-in' syndrome is actually a real thing. The affected person is fully aware and unable to move any part of their body except their eyes.
They could also get 'Total Locked-in syndrome', which paralyzes the eyes too.
Powerful Katrinka 2 hours ago
I was recently hospitalized with dangerously low sodium levels. I ended up in the ICU for 6 days, as they s-l-o-w-l-y brought my sodium levels back up to normal. When I asked my doctor why they couldn’t speed the process up, he told me that too much sodium too fast could, and probably would, result in locked-in syndrome. I didn’t complain about how long it was taking again. Locked-in syndrome is my idea of hell.
#8
You won't know you're getting dementia. Your family/those around you will.
#9
I lost about 5 years off my life when i learned about cryptic pregnancy. HELL NO.
Bookworm 10 hours ago (edited)
If you don't know it's when you don't know your pregnant until the 2nd, 3rd trimester or go into labor. All the "I didn't know I was pregnant" people. So little to no time to plan (get supplies, read what to expect when you're expecting, choose an obgyn and pediatrician etc). Very stressful.
#10
That your own immune system can destroy your body.
uhMothaWasAHamsta:
My immune system went after my kidneys. Now I’m on dialysis and hoping to get on the transplant list. They put me on chemo to destroy my immune system just to make it stop so now it takes me forever to heal, if I ever do.
#11
Flesh eating bacteria can quickly lead to amputation and demise. According to the person from whom I learned this terrible ailment from, it's all but incurable, which reminds me... rabies.
#12
Well, there's the whole thing about prions and their effect upon the brain. That's spooky.
throwaway_78325:
As someone in healthcare, prion diseases. The more I learn about them the more I spiral. The random/genetic variants are the scariest but I live in an area where the majority of my friends husbands/boyfriends are hunters and bring home game meat and absolutely not, I politely decline any sort of meat they’re serving at their house. Keep that away from me.
noctenaut:
Prions.
Tiny little proteins inside your brain, they replicate themselves by folding and then forming out another prion.
Sometimes, they fold incorrectly, and then cause other prions to do the same - eventually, widespread misfolded proteins cause damage to the brain, and introduce prion diseases such as ‘Mad Cow Disease’ or ‘Fatal Insomnia’.
Prion diseases are unique, most pathogenic illnesses are caused by foreign bacteria, viruses, parasites and other tiny organisms - but prion diseases are caused by agents of your own body, not foreign.
As such, where antibiotics, antivirals and other means of therapy against a pathogen are largely effective - no such therapy exists against prion diseases. Cases are always fatal. A good example is fatal insomnia - as the prions damage the brain further and further, the ability to sleep becomes impossible and the victim must wait for the body to give up. Hell on earth.
Prions are also incredibly hard to destroy, being resistant to alcohol, radiation, boiling, freezing and other conventional sterilisation methods - sometimes slipping into the food chain via farm animals such as cows, (hence ‘Mad Cow Disease’).
The also differ from other pathogens in that a misfolded prion overrides other proteins’ normal behaviour and thus causes them to misfold too. No other pathogen has the same ability - weaponising your own tissue against you.
As such, the central nervous system and eye tissue of somebody with a prion diseases is extremely contagious and require specialist destruction.
#14
A woman could be suffering from symptoms of a heart attack and pass it off as some acid reflux.
Tea Drinker 5 hours ago
And be misdiagnosed in the ER because women's symptoms aren't quite the same as a man's.
#15
Your nerves are as thin as strings. First time I opened up a body and studied all the anatomy, it was shocking how nerves and blood vessels were incredibly thin. Like we get hit by balls or fall on rocks or do martial arts and dont think much of it but the wiring of your entire body is so thin it's sobering to realize how fragile we really are.
Stephanie Did It 10 hours ago
Amazing that the image above is the basic operating system radiating from our true self, the brain. Everything layered over that is just accessories and window dressing.
#16
The brain is so powerful that it will make you sick just because you're stressed or traumatized. In Psychology, this is called conversion disorder. There are cases where a very healthy person can't speak or can't walk, and becomes bedridden due to underlying issues. Tests were made, but there are no signs or reasons why it happened. It's just your brain shutting you off.
314159265358979326:
I had one last year. Psychosomatic pericarditis. I had chest pain but the pericarditis symptoms didn't start until they mistakenly diagnosed me as having it. I was terribly disabled, basic household chores like unloading the entire dishwasher were impossible. Then 6 weeks later when I was supposed to be getting better, I got worse and went back in. They said it was just anxiety, and wouldn't you know it, I was cured in 10 minutes.
Gold Monkey 11 hours ago
Yeah, but doctors love to say that something is all in the patient's head just because the doctor doesn't know what it is. Just admit that and recommend a specialist, you twit.
#17
That some people are allergic to the sun, other humans and somehow water.
littleblissmiss:
I'm allergic to my own sweat.
#18
Creating life and birthing. That it can be life-threatening, even if you do everything right in your power.
#19
The most frightening fact about the human body:
Your brain does not distinguish well between real danger and repeated thoughts.
You stress about something imaginary → cortisol rises → the immune system drops.
In other words, you can get sick from a story that only exists in your head.
The mind is not “just mental.” It is real-time biochemistry.
#20
Your eating tube and breathing tube are literally separated by a tiny flap of skin.
Either God or evolution is a terrible designer.
#21
You can feel pain in a limb that isn’t even there anymore.
Phantom limb pain proves your brain can generate very real suffering without the body part existing.
Powerful Katrinka 2 hours ago
However, thanks to our old buddy neuroplasticity, it is curable.
#22
As far as understand of human anatomy and medicine has advanced over the last century, there is still so much we don't know. We don't know why the body does certain things, such as yawning. We don't understand the mechanisms behind why certain medicines/treatments work. We don't even know if we know all of the anatomy in a human body - entirely new organs are discovered on a surprisingly frequent basis.
Complicating things is that human anatomy is a spectrum. We think of it as a set thing, but there are so many possible variations.
#23
Your intestines are constantly moving around inside your abdomen like some kind of snake.
#24
Pregnancy related things get terrifying and dangerous quickly. Life might be precious, but nobody told nature. At least 25% of pregnancies end naturally in miscarriage without anyone doing anything wrong.
Anyone who tries to penalize or punish someone for miscarriage should be ashamed. It's already often painful and creates enough emotional upheaval, and sometimes trauma. The state has NO business getting involved in anything related to pregnancy.
Birth scars the bones and can cause tears. It's commonly traumatic, but nobody's supposed to talk about that side. I won't go into the insane costs from prenatal care through postnatal care. That shouldn't be forced on anyone against their will. There's a reason forced birth is a war crime.
#25
A forty-foot-long parasite (tapeworm) can fit inside you.
#26
There are more microscopic organisms living in and on your body than there are human cells. Made me question what it even means to be human.
#27
Fatal familial insomnia. Its a prion disease where your brain slowly loses the ability to sleep. Not like regular insomnia where you're tired but eventually crash - your brain literally forgets how to fall asleep. Average survival after symptoms start is like 12-18 months, and the whole time youre completely aware of what's happening to you. No cure, no treatment, nothing. Your brain just deteriorates while you're awake watching it happen.
#28
Intestines will move back into place on their own if they ever get misplaced, rearranged or out of order. I think anyone who’s had a c-section may have experienced this but it’s wild.
#29
Every single day mistakes happen in the creation of new cells and every single day there are hundreds and hundreds of cell mistakes made that could lead to a cancer. Luckily most of them will be eliminated before they do any damage, but the chance of some of them slipping through is never zero. Heck, there is a chance that right now that cancer is already growing.
#30
The spinal cord itself looks and feels like crab meat when it’s pulled out of the vertebrae.
#32
That disease where any injured tissue heals as bone. Absolutely fascinating and terrifying at the same time.
Also, Harlequin Ichthyosis.
#33
Postpartum cardiomyopathy—suddenly develop heart failure after pregnancy with no risk factors.
#34
How quickly the body perishes in an emergency. For example, if your survival depends on a defibrillator, every second *literally* counts. After 3 minutes, your chances of survival are pretty grim.
#35
That you can lose all your teeth during pregnancy because if you're not taking enough calcium rich foods, your foetus can take all the calcium from your teeth.
I actually saw a case like that on the internet.
Zig Zag Wanderer 9 hours ago
Free dentistry when pregnant in many civilised countries because of this. If dentistry isn't already free, of course (yes, Americans, I know we actually pay for it with taxes!)
#36
Your brain can quietly rewire itself to normalize almost anything, chronic pain, bad sleep, even anxiety, if it lasts long enough, your body starts treating it as the new normal which is why problems can creep in so slowly you barely notice until you are deep in it.
#37
That we know very little about the brain still!
#38
That you can have multiple symptoms and not one doctor can tell you what’s wrong!!! I am living proof.
David Paterson 1 hour ago
Need more information. Are the symptoms life-threatening? It's an annoying medical fact that thousands of different causes can have the same symptoms.
#39
Psychosis/mania- had it year ago and it still haunts me, the thoughts&thinking is 100% faster, you cant decide what you want to do, you have so much energy, alter-images (you think you re all powerdul being etc) you feel like you re top of the world, you cant fall asleep and you feel like you dont need to sleep, and it lasted up to 4 days for me, it was horrible thing to go through.
#40
Thinking about how quickly viruses can mutate and spread makes you see everyday germs a bit differently.
London Paris 4 hours ago
But not if you support maga and pray to baby jeebus . . . . . thems folks that dont see nothing and dont NEED to see anything cos baby jeebus loves them right proper 🤪
#41
Fallopian tubes aren’t attached to your ovaries, they just kind of wave around in your abdomen trying to grab the eggs when they fall out. It makes me picture my womb as salad fingers.
Ace 7 hours ago
Originally named, by their discoverer Gabriele Falloppio , as "tuba" due to their resemblance to the musical instrument of that name (not like the modern tuba, think more a Roman trumpet) . Plural of tuba in Italian is tube (pron. tube-eh) so when his work was published showing the two tubas it was translated as tube, then (re-)pluralised.
#42
Your brain can rewrite your memories and you’d never even know.
#43
Your kidneys are selfish, temperamental, and melodramatic. They'll end you if they want.
Heart is weak? Welp, the kidneys need blood, so they'll retain fluid to overwork your already weak heart just to get that sweet sweet blood.
#44
No matter how healthy you are through proper nutrition, good sleep and exercise you could still drop from a number of things you can't really do anything about. Aneurysm, heart attack, a blood clot or stroke can just happen due to bad genetics, too much stress or even just one really bad cough or sneeze.
I'm not afraid of most things people are commonly afraid of. However I'm terrified of my body just one day saying F you. That, sky diving and being in unclear water are some of the only things I have a legit fear of.
#45
Not really a fact, but I watch My 600-lb Life and it's scary how much the human body can handle.
Some guy on that show is 900 lbs. Some girl in this show is 800lbs and she's running around and walking.
#47
Your eyes can detatch.
Stephanie Did It 10 hours ago
Your retinas can detach. They are stretched across the very rear of the eye and can be dislodged by a hard blow or simply by age and stress from the shape of the eyeball (e.g. myopic, or near sighted eyes, are oblong). Both of mine have spontaneously detached, but repaired with laser surgery.
#48
You can feel completely fine while something life-threatening is already happening inside you.
#49
It's rare but the fact that sometimes plants can grow inside of you. Apparently some plants aren't picky because sometimes the inside of the human body isn't too different from dirt for them. I once heard about a plant that grew out of a man's heart of brain or something. That freaked me out so bad that it was constantly on my mind during fall of 2020.
J. Clark 6 hours ago (edited)
When we were children, my brother for some reason shoved a bean up his nose goofing around(we were young) and he was too afraid to tell anyone for a couple of weeks?a few days-but anyway it began to sprout while in his nose...a doctor removed it and showed it to all of us warning us not to stick beans up our noses as if we all had my brother's same sense of comedic artfulness.
#50
I find it kinda freaky that the heart never stops pumping. Like from the moment were born to the very end, it's just a constant movement.
#51
Feculent vomiting can happen. It’s rare but it can happen.
Bookworm 9 hours ago
Exactly what it sounds like. This is typically caused by some type of blockage in the intestines. It's also a major medical emergency so if this happens to you go to the ER immediately. Call an ambulance if needed. This is definitely not the time to try waiting to see if it gets better on its own.
#54
Not a specific fact, per se, but just the almost infinite ways the body can break down or fail. The space of possible problems is vast, and even the amount of rare disorders is huge. Every so often, I'll stumble across a new horrific condition I've never heard of, or I'll hear of a friend or family member's medical woes, and I'm reminded of how frail we are.
It really makes me appreciate how miraculous and complicated a functioning human body is at the end of the day. I'm grateful to only have run of the mill issues, like migraines and depression. The menu of worse conditions is unfathomable.
#55
Vitamin C is essential for the production of collagen. Scar tissue is constantly reworking itself and if you don’t have an incoming supply of collagen for them to do that, they just… open up. So if you get scurvy, all your old scars could just melt open on ya. Eat your citrus, kids!
#56
It's more disturbing than scary, but the fact that we are supposed to feel our organs moving, but the brain just ignores it.
#58
Gynecomastia affect 35% of men.
#59
I learned from my anatomy class that tumours try to keep arteries close to them so they can have oxygen rich blood so they can grow bigger. I think that was the scariest thing I’ve learned because I now don’t believe that cancer is treatable. Because it tries to keep oxygen for itself so I can grow bigger.
Gold Monkey 10 hours ago
You don't believe cancer is treatable? Then you're ignorant. It's treated all the time, successfully.
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London Paris 4 hours ago
Whats truly astounding is that we are at the very beginning of modern medicine, literally at the dawn of " modern medicine" and rhere is STILL so much to discover. You can get essentially pain free, infection free, almost routine medical investigations and cures for conditions that a mere TWO GENERATIONS AGO were considered death sentences . . . . .Safe insulin wasnt available before the 1980s ( it was taken from animals and could have severe allergic reactions) and we STILL hace no CURE for diabetes and dont even REALLY understand how or why it happens. . . . . . Model T ford times of medicine yet its still amazing.
London Paris 4 hours ago
Whats truly astounding is that we are at the very beginning of modern medicine, literally at the dawn of " modern medicine" and rhere is STILL so much to discover. You can get essentially pain free, infection free, almost routine medical investigations and cures for conditions that a mere TWO GENERATIONS AGO were considered death sentences . . . . .Safe insulin wasnt available before the 1980s ( it was taken from animals and could have severe allergic reactions) and we STILL hace no CURE for diabetes and dont even REALLY understand how or why it happens. . . . . . Model T ford times of medicine yet its still amazing.
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