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The human body is one of the most complicated and trickiest living forms on Earth. Even though we have a lot in common, there´re certain unique features that make each human body special. Here are some interesting features that make it special. For example, did you know that around 6% of people can rapidly shake their eyes back and forth? Sounds like a great party trick. Wanna take a look at it?
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00:00Yep, I think it's safe to say that falling from any height can be really dangerous.
00:04But especially when you've tumbled out of an airplane.
00:07And worse, without a parachute.
00:09Now, the trick here is to create drag to slow your descent.
00:13Use your shirt, pants, or do an air snow angel.
00:16Anything to slow you down a little bit.
00:19But hey, you've always wanted to make an impact, right?
00:22Well, check this out.
00:23A Yugoslavian woman was working as a flight attendant.
00:26She survived an incredible fall on January 26, 1972, after the plane she was working on exploded.
00:34Falling from a height of 33,000 feet, she managed to survive,
00:39but spent the next year and a half recovering after waking up from her coma.
00:43Experts disagree on the right way to land, but there's definitely a wrong way.
00:48Landing on your head.
00:49Do you remember the rule of three for us squishy human beings?
00:53Uh, that's you and me, by the way.
00:55Three minutes without oxygen.
00:58Three days without water.
01:00Three weeks without food.
01:01It's a great guideline, but some people manage to stretch it out a bit further.
01:06If watching a sunset, smelling flowers, or ordering that big juicy hamburger is important to you,
01:12well, you better start thanking that delightful gas, oxygen.
01:16Don't believe me?
01:17Try doing even one of those things without it.
01:21Two minutes without oxygen will cause the average human to pass out.
01:25After 10 minutes, well, there isn't usually a comeback to her.
01:29This varies, of course, from person to person, depending on their fitness levels.
01:33But we love to push the boundaries as humans, don't we?
01:37The longest someone held their breath for was an outstanding 24 minutes, 3.45 seconds.
01:45Give or take.
01:46That's 100 times longer than the first airplane flight.
01:49Take that, Wright brothers.
01:51Alex Segura Vendrell from Spain pushed the limits of breath-holding in 2016 by floating in a controlled pool environment.
01:59Just before going under, he was gulping in air like a fish to try to get as much oxygen as
02:05possible.
02:06Strangely, holding your breath underwater is easier than trying it on dry land.
02:10Swimming activates your diver's reflex, slowing down our heart rate and metabolism.
02:16Not only is oxygen important, so is precious H2O, a hand-tasty food.
02:21Each cell in our body needs water to survive.
02:24If we can't replace the water loss quickly, we only have about three days to a week before it's all
02:31over.
02:31How humid the air is, our age, physical activity, and health play a huge part in water retention in our
02:38bodies.
02:39When we're running low on water, the important areas of our body, like the heart and brain, pull water from
02:46wherever it can.
02:47Like a sponge, these organs soak up everything until there's nothing left.
02:52In 1979, an Austrian man in a holding cell lasted 18 days without water.
02:59He allegedly lit condensation off the prison walls to stay hydrated.
03:04What's the scariest thing in the universe?
03:06The fridge is empty! Where's all the food?
03:09Without any calories, your body starts to feed on itself.
03:14Not exactly the diet I had planned for this year.
03:17During the first few days, our carbohydrate reserves are turned into glucose.
03:22When that's all used up, our body starts to target fat, muscle, and other proteins,
03:27all the way down to the bones.
03:30Fasting is a common way to let our bodies use those extra reserves inside of us.
03:35Mahatma Gandhi's longest of many fasts lasted 21 days.
03:40The longest known fast was when a 27-year-old lived off water and vitamin supplements for 382 days
03:47and shrank from 456 to 180 pounds.
03:52Yow!
03:52Our bodies are equipped to survive without food for long periods.
03:56Our ancestors didn't exactly have a supermarket to go to.
04:00This makes us pretty good at dealing with starvation.
04:04We humans can cope with many extreme survival situations.
04:07But how long can you swim in freezing water without turning into a popsicle?
04:12What happens if you're stuck in the desert or at the top of a mountain?
04:16Climbing the peaks of the world, like the Rocky Mountains, the Swiss Alps, or even Mount Everest,
04:22is challenging on a good day.
04:24But the real danger is altitude sickness.
04:26It affects about half of all climbers.
04:29Starting at roughly 1.5 miles up, the lack of oxygen can cause dizziness, tiredness, and headaches for some.
04:37Others can even get insomnia.
04:39This is just the start of a whole bunch of symptoms that affect our bodies.
04:44Consciousness becomes a big problem for most people at 3 miles up, without proper preparation.
04:50Ascending too quickly can even lead to fluid in your lungs, or even worse.
04:55The thing about altitude sickness is that it doesn't care if you're old or young, male or female,
05:02a couch potato, or an athlete.
05:04Everest is 5.5 miles high and the ultimate challenge for climbers.
05:09That's like hiking up 20 Empire State Buildings or two times the Hollywood Walk of Fame.
05:15Austrian Felix Baumgartner pushed the altitude tolerance limit on October 14, 2012.
05:21He jumped from 128,000 feet up.
05:25That's nearly 24 miles.
05:27It's no surprise that he's also the first skydiver to go faster than the speed of sound,
05:33reaching a mind-boggling 833 miles per hour.
05:36He definitely had the right equipment, like a pressure suit with oxygen and safety checks
05:41in place, which goes to show you, if you're going up high, remember the 5 Ps.
05:47Proper planning prevents poor performance.
05:50Surviving extreme heat isn't just about the temperature.
05:54Humidity is the real danger to us.
05:56The less humid the air is, the more water stays where it belongs, in our body.
06:01Ever walked into the sauna and realized that it's over 230 degrees?
06:06That's so hot and humid, you'd probably only last about 3-4 minutes max.
06:11Wait, humans can't melt, right?
06:14Above 104 degrees, there's a real chance of heat stroke.
06:18It doesn't sound like a big change from our usual body temperature, but it is.
06:23Just imagine getting caught in a desert for a few days.
06:26And not just any desert, the world's hottest.
06:29The hottest temperature ever recorded on Earth was in Nevada.
06:33A crazy 134 degrees.
06:36Cooling way down, really quickly, can help relieve cramps, headaches, and even nausea.
06:42But breathing can become kinda impossible once your organs start to shut down and hypothermia sets in.
06:48As soon as our bodies drop below our natural body temperature, our muscles start to stiffen.
06:54That's why you stop feeling cold and pain after a while.
06:57There just aren't any nerve endings functioning anymore.
07:01Shivering quickly to produce heat is our body's natural way to keep our organs warm.
07:06This only works for cold air, though.
07:08In cold water, shivering drains your body heat even faster.
07:12If you've never heard of the 300 Club, you're not alone.
07:16A base in Antarctica has found a great way to test the extreme limits of the human body in the
07:22most peculiar way.
07:24Participants at the station warm up in the sauna, which is heated to 200 degrees.
07:29Then they pull on their boots and run outside, where it's minus 100.
07:34Not only do they have to endure the 300-degree temperature change,
07:38but they've also got to run around the South Pole before coming back to the sauna to warm up again.
07:47Sleep is very important.
07:50Maybe that's why getting out of bed in the morning is so tough.
07:53We need sleep to recharge our body from the long day we've just had,
07:57leaving us refreshed and alert when we hear that alarm.
08:01Our brain can turn all fuzzy without enough sleep,
08:04and a good 8 hours is perfect for a healthy immune system.
08:07Sleeping improves our memory, our heart, and puts us in a better mood for the day.
08:13Randy Gardner and his friends tried to test the limits of staying awake.
08:17It was for their science fair project.
08:20They managed to stay awake and functioning for 11 days and 25 minutes.
08:25Even when tested during and after the experiment,
08:28Randy could play basketball and had no abnormal brain waves.
08:32Now, it's almost impossible to calculate the exact G-force that would harm a human.
08:37That's because there are three types of G-force out there.
08:41Side to side, up and down, and forward and backward.
08:44The danger lies in how long we have to sit there while we're being thrown around like a ragdoll.
08:50The longer we sit there, the more it affects our bodies.
08:53We experience G-force at home simply by sitting down on the couch too quickly,
08:58sneezing, or having someone slap our back a little too hard.
09:03Pilot John Stapp demonstrated that a human can withstand over 40 Gs.
09:08That's nearly 10 times the amount an average racing driver feels.
09:12The experiment only went on for a few seconds.
09:15But for an instant, his body weighed almost 7,000 pounds.
09:20Survival isn't always about taking on the elements.
09:23Sometimes, it's fighting against time.
09:26The current record for the longest-living human is Gene Kalman, who was born in 1875.
09:36Ay-yi-yi!
09:38About 6% of people can vibrate and rapidly shake their eyeballs back and forth.
09:43It doesn't mean something's not right with their eyes.
09:45It's just a unique trick they can perform.
09:48Good at parties, I suppose.
09:50Your bones are designed to be used a lot daily,
09:52and some of them can absorb 2 or even 3 times your body weight.
09:56That's impressive, but your teeth are even stronger.
09:59When you bite something, the teeth can exert incredible pressure, up to 200 pounds.
10:05By the way, the enamel is considered to be part of your skeletal system.
10:09Your stomach has a pretty incredible capacity,
10:12being able to hold up to half a gallon of liquid, a whole large bottle of Coke.
10:16It's pretty hard to estimate how much hard food you can squeeze into your stomach,
10:21since the food is processed with your teeth before it gets inside.
10:24There's definitely not enough room for a turkey,
10:26but a good-sized chicken will probably fit it.
10:30Whenever you rotate your hand, the bones inside it actually intersect.
10:35Grab your hand and verify it.
10:36Yeah, not very useful.
10:38Now, show me where your stomach is.
10:40If you're pointing at your tummy,
10:42sorry, but it's wrong.
10:44It's up here, hidden between your ribs.
10:46Fun fact about bones.
10:48You know that your body is about 60% water, right?
10:51What's new here is that your bones are in this too.
10:54About 25% of the human bone mass is made up of water.
10:59Scientists believe that the appendix isn't here to stay.
11:02Nobody really knows why we need it,
11:04but some researchers claim it helped our ancestors process the tree bark they were eating.
11:09As it's no longer part of our daily diet,
11:12the appendix can disappear from our bodies without any consequences.
11:15A human eye has some resemblance to a car engine.
11:19They both need various liquids to perform properly.
11:22An engine needs gasoline, and an eye needs tears.
11:25In order to work well, the tears should be thoroughly distributed all over the eye.
11:29That's why we blink up to 20,000 times a day.
11:33So, a lid is a bit of a windshield washer.
11:36Almost all of our body is covered with hairs, even if we don't notice them.
11:40They grow even in the belly button.
11:42Their purpose is to catch lint.
11:44The only part of the human body that doesn't get any nutrients from blood
11:48is the cornea of the eye.
11:50Instead, it's fed by tears and fluid in the front of your eyes.
11:54If you never knew you had a personal bodyguard,
11:57look deeper.
11:58Your liver is your security guard,
12:00protecting you from toxins and many other things you don't want to have.
12:04It's also pretty indestructible and can even regenerate.
12:08When you blush, it means there's an increased blood flow in your body.
12:12Not only do your cheeks get somewhat red, but your stomach lining too.
12:16It's because it has plenty of blood vessels,
12:18and when there's more blood than usual, it turns red.
12:22Only about 43% of you is actually you.
12:25You're over 50% tiny little creatures that mainly live in your gut and other body parts
12:30without ever leaving it.
12:32Still, even though your own cells are fewer than microbial ones,
12:36there are, on average, about 100 trillion of them in you.
12:40Let's count them.
12:41You start.
12:42Your stomach has a lining replaced every 3-4 days.
12:46That's done to stop it from eating itself.
12:48The digestive acids we've got can be pretty damaging.
12:51One thing that surely rests while you're sleeping is your nose.
12:55You just won't smell anything nasty in your sleep.
12:58The thing is that your sense of smell basically deactivates at night.
13:02If there's some really terrible smell in your bedroom, you won't even be bothered.
13:07We can accidentally digest small objects,
13:10such as plastic items, glass, coins, and many other small objects.
13:14They pass their way through the digestive tract within 48 hours.
13:17Really?
13:18Just trust me on this one.
13:19You have better things to do.
13:21Scientists used to believe we could distinguish about 10,000 smells.
13:25Nope.
13:26Recent research showed that people were able to distinguish more than a trillion smells.
13:31We also remember them better than anything else,
13:33and smells can even evoke some distant memories.
13:37We can digest tiny quantities of plastic,
13:40but the human digestive system can't really bear grass.
13:43Grazing animals have special teeth
13:45and several stomachs to process raw leaves and grass.
13:49Well, we have none of that stuff.
13:51But don't feel bad.
13:52Among mammals, only humans can always walk on two hind limbs
13:56and keep that posture for their entire lives.
13:58You might object that kangaroos or gorillas move in the same way,
14:02but the roos use their tail as a third leg,
14:05and gorillas use the help of their long arms to keep balance.
14:08The stomach is the most important defender of the immune system.
14:13Hydrochloric acid in our stomach kills dangerous food toxins,
14:16viruses, and bacteria that get in there with the food you eat.
14:19This acid can digest even the stomach itself,
14:22but the mucous membrane protects it.
14:25Body fat isn't just a nuisance.
14:27It acts as insulation material, energy reserve, and shock absorber.
14:31Your body sends the most fat into your waist region
14:34because that's where your internal organs are.
14:36If something happens to you,
14:38this layer of fat might as well protect your vitals from irreparable damage.
14:42We've got two really fast muscles.
14:45They control the eyelid closing.
14:47These are the fastest muscles in our body.
14:49Eyes are fragile and need protection.
14:51That's why, when the reflex is triggered,
14:54these muscles shut the eyes within about 100 milliseconds.
14:57That's not more than 0.1 second.
15:00We recognize only purple-blue, green-yellow, and yellow-red colors.
15:04Everything else is a combination of these three.
15:07It's impossible to calculate how many of these combinations the human eye sees
15:11because every person has slight visual differences.
15:14But it's about 1 million combinations on average.
15:18Now, even if you brush your teeth twice a day and never forget about mouthwash,
15:22your mouth still stays one of the dirtiest parts of the human body.
15:27Ew.
15:27Millions of bacteria live inside it.
15:29The good news is that most of these bacteria are good for the body
15:33and protect it from bad bacteria and viruses.
15:36The second dirtiest place is the belly button,
15:39and it's probably because it's the first ignored place.
15:42The thing is, we don't really use them after we're born,
15:45so this forlorn area accumulates all kinds of germs, sweat, and dirt.
15:51The belly button has over 2,300 bacterial species,
15:54and it does need extra attention.
15:57You think you owe your strong handshake to all your strength workouts?
16:01Well, you're more likely to owe it to your pinky.
16:04Just kidding.
16:05Anyway, a pinky is the strongest finger out there.
16:08This humble finger is responsible for 50% of your hand strength.
16:12Still, the most used finger is the thumb.
16:15It takes to itself 40% of the hand's action.
16:19Well, it probably makes it the most important finger, too.
16:21Two more humble helpers are your toes that carry about 40% of your weight.
16:27If you've ever heard that humans don't really need their toes, don't believe it.
16:31They're also the main pushers when you walk.
16:34Tomatoes have more genes than humans.
16:36This shouldn't concern you, though, because it's not the number of genes that matters,
16:40but the complexity of their connections.
16:43Nails don't only help us catch random objects and peel the stickers off.
16:47If you didn't have a rigid structure against which to press,
16:51you wouldn't be able to judge how firmly to hold anything.
16:54Our hair color is easily explained by genes.
16:57There are not more than 2% of people with naturally red hair.
17:01They're followed by blondes, about 3%.
17:03And all the varieties of brown shades, only about 11%.
17:07The vast majority goes to black hair, including very dark brown.
17:13Yeah, your hair can stop growing at a certain length.
17:15A hair usually grows from 2 to 7 years.
17:18So usually it doesn't exceed 42 inches.
17:22Well, tell that to this gal from China,
17:24who broke all the hair records with the longest hair ever.
17:27In 2004, her hair was 18 feet, 5 and a half inches long.
17:33Rapunzel, where have you been, girl?
17:35When we laugh, think, look at something, dream, move,
17:39or do some other activity with our body,
17:41small electrical and chemical signals run between neurons along those connections.
17:46Our brain is always active,
17:48sometimes even more when we're sleeping than when we're awake.
17:51And by that, neurons make and send more information
17:54than all the phones in the whole world.
17:57You're sitting somewhere outside,
17:59and an insect lands on your leg.
18:01Your skin has sensory neurons,
18:03and they quickly send the message to your brain
18:05at an impressive speed,
18:06150 miles per hour.
18:09The brain sends back the message to your leg
18:11to shake the insect off very fast.
18:13And the speed that information travels
18:15is even bigger,
18:16200 miles per hour.
18:19Now, toenails grow around 4 times slower
18:21than your fingernails.
18:22This happens because we do more things with our hands
18:25compared to feet,
18:26which is why we cause more trauma to our fingernails.
18:29Now, there's a high possibility
18:31your right hand has different types of microbes
18:34than the left one.
18:35This happens because they cover our skin from head to toe,
18:38and their variety depends on our skin thickness,
18:41humidity, temperature, texture, and chemistry,
18:44which can change as we use our right and left hands
18:47in different ways.
18:48Our nails and hair are made of keratin,
18:51which is a material we find in certain body parts
18:54of some other animals as well.
18:55For instance, claws, hooves, horns,
18:58wool, fur, feathers, beaks,
19:01turtle shells, and porcupine quills.
19:03Our body is made of stardust.
19:06Really?
19:06The more complex elements in our body
19:09can only come about through supernovas.
19:11The first stars were just gassy lumps
19:14that were drawn together
19:15and, at some point,
19:16started the process of combustion.
19:19This finally led to a nuclear reaction
19:21in its center.
19:21Stars that were there right after the Big Bang
19:24were over 50 times bigger than our sun is now.
19:27Inside of them,
19:28there was a constant process of making the elements,
19:31and those large stars
19:32were burning their fuel faster.
19:34Most of the elements in the human body
19:36were formed in those stars
19:37over billions of years,
19:38so you could realistically say
19:41that part of you is immortal.
19:43Not even twins have tongue prints that are alike.
19:46The tongue is a movable and strong set of muscles
19:50that almost never gets tired.
19:52It contains anywhere from 5,000 to 10,000 taste buds.
19:56Those little white and pink bumps on your tongue
19:58aren't taste buds,
20:00but each of them does have a bunch of them
20:02inside its surface tissue.
20:04Evolution gave us taste buds
20:06so that we can stay alive.
20:08For instance,
20:09sour and bitter flavors
20:10can be a sign
20:11that you may be eating rotten food
20:13or poisonous plants.
20:15The back of the tongue
20:16is more sensitive
20:17when it comes to bitter flavors,
20:19which is why we can spit out bad food
20:21before we swallow it.
20:23Salty and sweet tastes
20:24tell us if foods are rich in nutrients.
20:27By the time they're 60,
20:29the majority of people
20:30lose half their taste buds.
20:32Yes, your tongue is pretty cool,
20:34and its prints can be used
20:35for biometric authentication,
20:37just like fingerprints.
20:39Each of us have a different
20:40and unique tongue print.
20:41So, if you don't want to reveal
20:43your secret identity,
20:45keep your tongue hidden.
20:46Huh, that would be funny.
20:48Why do we even have fingerprints?
20:50Scientists had a lot of different theories,
20:52but they now believe
20:53it's because having them
20:55allows skin to stretch more easily.
20:57That prevents blisters,
20:59protects the skin from damage,
21:00and may improve our sense of touch.
21:03Humans are not the only ones
21:04with unique fingerprints.
21:06Koalas have them too.
21:08Only around 7% of people
21:10are left-handed.
21:12Left-handed people mostly chew food
21:14on the left side of their mouth,
21:15while right-handed people
21:17do so on the right.
21:18We lose almost 9 pounds
21:20of skin cells every year.
21:22Don't worry,
21:23we replace them quickly.
21:25We produce more cells
21:26than there are people
21:27living in the United States
21:28every 15 seconds.
21:30Our body is always regenerating,
21:32and we replace our skin
21:34hundreds of times
21:35during one lifetime.
21:36Yep, our body regenerates,
21:39except for our teeth.
21:40They're the only part of the body
21:42that can't heal itself.
21:44We have teeth
21:45that are similar to a shark's.
21:47Their teeth also have a thing
21:48called dentin inside of them,
21:50and theirs are just as strong as ours.
21:53Of course,
21:53theirs are sharper and bigger,
21:55but still.
21:56Teeth are part of the human skeleton,
21:59but they're not considered bones.
22:01You'll spend approximately
22:0238 days of your life
22:04brushing your teeth.
22:05And guess what?
22:07It's possible to brush them too much.
22:09That can make them more sensitive
22:11because it wears down
22:12the natural enamel.
22:13Your left and right lungs
22:15are not the same size.
22:17The right one is bigger
22:18because the left
22:20shares its real estate
22:21with your heart.
22:23Hiccups are something
22:24almost all mammals go through
22:25from time to time,
22:27not just humans.
22:28The record was set
22:29by a man named Charles Osborne.
22:31He couldn't stop hiccuping
22:33for 68 years.
22:34Guess no one told him
22:35about the whole
22:35eating sugar trip.
22:37There's only one part
22:38of your body
22:39that doesn't get
22:40a regular delivery of blood.
22:41Your corneas.
22:43They get oxygen
22:44directly from the air.
22:46Our eyes can differentiate
22:47between 10 million
22:49different colors.
22:50The muscles that help
22:51our eyes focus on something
22:52make around
22:53100,000 movements a day.
22:55If you wanted to make
22:57your leg muscles
22:57do the same amount of work,
22:59you'd need to take
23:00a long walk,
23:01at least 50 miles.
23:03We can't all see
23:04infrared light
23:05or ultraviolet radiation.
23:07Only 1% of us
23:09can do that.
23:09And if you can see
23:11one of those,
23:11it doesn't necessarily mean
23:13you can see the other.
23:14Research says
23:15blue-eyed people
23:16all over the world
23:17may be related,
23:19or at least share
23:20a very distant ancestor.
23:22Scientists looked
23:23at blue-eyed individuals
23:24from Turkey,
23:25India,
23:26Jordan,
23:26and Scandinavia.
23:27They all had the same
23:29eye color gene sequences.
23:31They believe this trait
23:32comes from one
23:33blue-eyed person
23:34whose genes mutated
23:36around 10,000 years ago.
23:38Before that,
23:39people's eyes
23:40were just all different
23:41shades of brown.
23:42People with blue eyes
23:44are generally
23:44a bit more sensitive
23:45to pain
23:46than individuals
23:47with other eye colors.
23:49We blink about
23:5020 times in one minute,
23:51which means
23:52we do it
23:53more than
23:5310 million times a year.
23:55That thing about
23:56being similar to sharks?
23:58Well, that goes
23:59for our eyes, too.
24:00If part of your eye
24:01gets damaged,
24:02you can replace it
24:03with a shark's.
24:05We can't sneeze
24:06with our eyes open.
24:08Try it.
24:08It's really hard
24:09to override
24:10your built-in reflexes.
24:12Eyelashes
24:13have their own life, too.
24:15One single lash
24:16lives for about
24:17150 days
24:18before falling out.
24:20We all get goosebumps
24:21when we hear
24:22Good News,
24:23our favorite song,
24:24or when it's
24:25ridiculously cold
24:26in the frozen food aisle.
24:27It's a reflex
24:28we got
24:28from our ancestors.
24:30It happens
24:31when you release
24:31adrenaline.
24:32It makes your hair
24:33stand on end
24:34and helps you
24:35look more imposing.
24:36Roar!
24:37Scary, huh?
24:39The human brain
24:40has 100 billion neurons
24:41and a memory capacity
24:43that's equal
24:44to more than
24:444 terabytes,
24:46which is a lot.
24:47Your brain
24:48uses more than
24:48a quarter
24:49of all the oxygen
24:50your lungs take in,
24:51and it's mostly water.
24:53More than 75%.
24:54Stay hydrated, people.
24:57It's not true
24:58that humans use
24:59only 10% of their brain.
25:00We use much more
25:01than that,
25:02even when we're asleep.
25:03Most of our brain
25:04is constantly active.
25:06We just don't use
25:07all parts of it
25:08at the same time.
25:09Out of all the species
25:10out there,
25:11humans are the only ones
25:13who can blush.
25:14It comes from
25:15a rush of adrenaline.
25:16When you see
25:17your face turn red,
25:18know that your stomach
25:19is turning red, too.
25:21How weird is that?
25:22When you crack
25:23your knuckles,
25:24the sound you're hearing
25:25is tiny gas bubbles
25:27being released.
25:28There are pockets
25:29of gas trapped
25:30between your joints,
25:31so when you stretch them,
25:33they make a popping noise.
25:35Ugh, so satisfying.
25:37Ah!
25:38We use 43 muscles
25:40when we frown,
25:40but only 17
25:41when we smile.
25:43No scientists
25:43are still arguing
25:44over this one.
25:46Say cheese!
25:46An average person
25:48eats around
25:4933 tons of food
25:50over a lifetime.
25:52That's six elephants' worth.
25:55We breathe in
25:56approximately
25:562,900 gallons
25:58of air
25:58on a daily basis,
26:00but we can't swallow
26:01and breathe
26:02at the same time.
26:03Most people need
26:04about seven minutes
26:05to fall asleep,
26:06and we're just about
26:08the only living creatures
26:09that sleep on our backs.
26:11Randy Gardner
26:12decided to set the record
26:13for the longest period
26:14without sleep.
26:16The year was 1964,
26:18and he stayed awake
26:19for 11 days.
26:20That's 264 hours.
26:22Guess he had
26:23pretty noisy neighbors.
26:24Amongst all animals,
26:26humans are the only ones
26:27with chins.
26:29When you're thirsty,
26:30it means the water loss
26:32you're experiencing
26:32is equal to 1%
26:34of your total body weight.
26:36If it goes past 5%,
26:37you might even faint.
26:39During your lifespan,
26:41your body goes from
26:42having 300 bones
26:43to 206.
26:45Over half of all your bones
26:46are in your feet,
26:47your ankles,
26:48hands,
26:49and wrists.
26:50The biggest human bone
26:51is the thigh bone,
26:53and the smallest one
26:54is called the stirrup bone.
26:56It's inside your eardrum.
26:58Your nose can recognize
26:59a trillion different scents
27:01and remember 50,000 of them.
27:03Also,
27:04women are better smellers
27:05than men,
27:06and our sense of smell
27:07is 10,000 times more sensitive
27:09than our sense of taste.
27:11Our lungs have a surface area
27:13that's almost equal
27:14to the area
27:15of an entire tennis court.
27:17So,
27:17what's up with that feeling
27:19you get when you're going
27:20over a crest
27:20on a roller coaster
27:21and your stomach
27:22jumps up into your throat?
27:24Well,
27:24the seat belt
27:25keeps your body in place,
27:26but your stomach,
27:28intestines,
27:28and smaller internal organs,
27:30get a little air time.
27:32It doesn't do you any harm,
27:34but your nerves
27:35can't figure out
27:36what's going on.
27:37They really think
27:38your stomach has jumped
27:39all the way
27:39into your throat.
27:41We're all taller
27:42in the morning
27:42because,
27:43throughout the day,
27:44the cartilage between our bones
27:46gets compressed.
27:47That makes us
27:48around one fingernail shorter
27:50by the end of each day.
27:52Nose and ears,
27:53parts of our body
27:54that never stop growing.
27:55It's mostly thanks to gravity.
27:57The veins and arteries
27:59inside your body
28:00are long enough
28:01to make two trips
28:02around the world.
28:03Blood makes up
28:04about 8%
28:05of your body weight.
28:06When you listen to music,
28:08your heartbeat syncs
28:09with the general vibe
28:10of the song.
28:11So,
28:11choose wisely.
28:12Your skin
28:13is the biggest organ you have.
28:15It counts for about
28:1615% of your total weight.
28:18Get this,
28:19you can burn more calories
28:21during sleep
28:22than when watching TV.
28:24Hmm,
28:24and what about sleeping
28:26while the TV's still on?
28:27You can burn more calories.
28:27You can burn more calories.
28:27You can burn more calories.
28:27You can burn more calories.