We can dive tens of meters into the ocean on a single breath or climb thousands of meters toward the sky to summit the tallest pizza.

But sometimes our bodies also do stuff that's pretty weird roasts or just plain annoying.

Over the years we hear it, sideshow have talked about a lot of these other everyday things that our bodies do.

And apparently our patrons are big fans of these episodes.

When we asked them to pick a compilation topic, they voted for us to smush a bunch of Why do we episodes into one?

So here we go first.

You've probably laughed at some point today, and if not, well, hopefully you will in the next 15 minutes or so.

At least we'll try to make it happen anyhow.

Laughing is just one of those things.

All people do.

We laugh when we're amused and when we're anxious.

But why?

What's the point of laughing?

Let's let Hank explain.

It was like super funny laughter.

Laughter is a physiological response that involves at least 15 facial muscles.

The respiratory system, the brain's limbic system.

And if the joke is really, really good, even your tear ducts thought laughter doesn't always indicate happy times.

It could actually be a sign that something is seriously wrong with your brain.

JJ, Elastic seizures or uncontrollable and random laughter or crying can indicate the presence of brain tumors or other conditions like pseudo bober affect a neurological condition that can affect stroke and brain trauma survivors and M s patients.

These conditions are sometimes called emotional incontinence because the sufferer can't control the outbursts, which often have no routine down there.

Feeling and how we feel, especially in groups, seems to be what laughing is all about.

Some laugh researchers.

And yes, they are things known as gelato ologists.

I think that much of our laughter is rooted in strengthening social bonds were much more likely to laugh in a group than we are alone, and we tend to laugh more easily around friends and family.

That shared experience brings us closer, makes us feel part of the group.

We also laughed to express relief or to ease our nerves in stressful moments.

Researchers theorize that there are a few specific reasons for laughing.

First, there's the incongruity theory, which maintains it's the element of surprise that triggers laughter, whether it's an unexpected punch line or your friend tripping over throw rug.

So like, say, you're watching people walk through a room all day, your brain registers this as predictable and boring behavior.

Then your friend walks in trips on a rug and drops a box of ping Pong balls.

Once you're sure that your friend hasn't safe fallen on a bag of rusty knives, you'll find the fall hilarious because it was sudden and unexpected and incongruous to the string of people you'd seem safely walking by.

And because ping pong balls, babies and little kids go for this kind of laughter a lot, they think really simple, unexpected things like my on my face is here.

It's cared for five consecutive hours.

It's still funny here, like using a banana is a telephone.

Now, if you're the one who tripped on the throw rug, you're much more likely to laugh and surprise if you see your friend laughing with you.

This goes back to that shared laughter as social bond thing.

You're probably feeling pretty embarrassed, intense, but are also relieved that you aren't hurt that's where the relief theory comes in.

Laughing is like a mental mini break.

Your brain is constantly working, taking in all sorts of information and ordering around the body.

Sometimes it just needs a happy surprise.

This is particularly handy and stressful moments.

The whole Hollywood wisecrack in the middle of a suspenseful scene phenomenon is predicated on this idea.

When Han Solo is in mortal danger, he cracks a joke to lighten the mood.

He needs it.

Chewie needs at the audience at the edge of their seats.

Need it?

Humor helps us cope with stressful situations.

It's sort of recharge is our brains to face the task at hand?

Scientists call this releasing cognitive energy the rest of us college comic relief.

But now back to you, tripping on that throw rug.

If everyone in the room is laughing at you and none of them are your friends, they may be proving the superiority theory of laughter.

It means that they're laughing at your misfortune and probably means that the kind of a bunch of jerk faces superiority.

Laughter still promotes bonding, and an US versus them kind of way doesn't show much goodwill.

Though teenagers make fun of their parents and you know each other and pretty much everyone, and so do lots of adults as well.

But our teen years aren't usually awkward and confusing and superiority.

Laughter may help ease some of that pain.

So simply put, we laugh hardest at what we know best and at what stresses us out the most.

And maybe that's why it's great for you, both physically and emotionally.

It reduces the release of stress hormones that jack those fighter flight feelings.

It lowers blood pressure and oxygenate your blood flow.

It even increases your T cell levels that help your immune response in B cells that produce antibodies.

Also laughing, Ah, 100 times is estimated to burn as many calories as a 15 minute bike ride.

So you see, laughter is not the best medicine.

But it's not a bad medicine, either.

Wow, there is a lot more toe laughter than I thought.

But of course, laughter isn't the only way we express emotions physiologically, for example, when we're embarrassed or cheeks turned bright red, whether we want them to or not, what other animals don't do this?

So why do we?

Here's Michael with some ideas in every culture and every ethnicity around the world.

People blush, but animals don't.

And it's not just that most animals faces air covered in fur and feathers and stuff, so we can't see them blushing.

They actually don't blush.

Charles Darwin called Blushing, the most peculiar and most human of all expressions, which is awesome.

But why do we blush physiologically we understand it.

I mean, we get the mechanics of why your face turns red when Bernie sneaks up behind you and pulled your pants down in front of the whole rest of the marching band Bernie's.

Anyway, your face turns red because your sympathetic nervous system kicks in.

That's the network of nerves that controls your fight or flight response.

When it's triggered, it signals the release of adrenaline, and suddenly your heart rate picks up and you start breathing faster, and then you're ready to run away.

Your pupils dilate and blood rushes to your brain so you can take in as much information as possible, and your blood vessels dilate in a process called vase oh dilation to improve oxygen flow.

It's basically the same effect you get from warming up before a workout, but in the very hypothetical instance of my pants being pulled down, the blood vessels in my face were responding specifically to a chemical transmitter called a dental psych lays.

It basically tells the blood vessels in your face to let the adrenaline in.

The weird thing is that these same superficial blood vessels in your face aren't usually affected by sympathetic responses.

I mean, we don't blush when we're scared.

If we did, that might be a sign that blushes served some sort of survival purpose.

But it only happens when we're not actually in danger.

So, like why?

Well, some scientists believe that blushes evolved is a social survival trait.

When you blush on the person who's angry, you can see that you're really sorry, and the person who's laughing at you can see that you're visibly embarrassed.

If that sounds weird, just think about the last time your dog chews on the furniture, then rolled onto its back when you got mad.

Lots of animals have evolved this sort of behavior so they can say, Hey, whoa, I messed up.

I feel terrible, and it's really hard to stay mad at your dog when it does that.

That's how you know it's working.

We may never know for sure why blushing became a thing, but it could just be our way of saying sorry for chewing on the furniture.

I never thought of it that way.

But blushing is a social signal does make sense, especially when you consider how often our bodies in voluntarily do things that are considered offensive.

Like we burp and fart a lot.

And while I get that we all have gas, why do we have to expel so much of it all the time?

Here's Hank to explain, formally referred to his belching and flatulent Thies.

Too often lampooned bodily functions actually share a common cause.

Swallowed air.

Every time you swallow, you take in some air, but you could swallow even more air than normal if you eat or drink too quickly to gun, smoke, drink carbonated beverages or even wear loose fitting dentures.

Now the majority of swallowed air comes back up in the form of burps.

As the air builds up in the upper portion of the stomach, it causes stretching that eventually triggers the lower esophageal sphincter.

To relax.

Result is air escaping off the esophagus into the mouth where the sound and smell of the verb depends on how much coke you just chugged.

Babies, in particular are big Berbers, especially further small size, mostly because they tend to go pin too much air while nursing.

And because young digestive systems haven't developed to the point where babies could easily burp on their own, it's up to mom and dad to pat their backs.

Help get those gas bubbles out.

But for babies and adults, what about the air that isn't burped out?

Well, it passes from the stomach into the small intestine and later the large intestine along the way as it passes through the gastrointestinal tract that air mixes with the products of some good old bacterial fermentation that's going on.

Your guts of fermentation is the result of carbohydrates like sugars and starches that can't be digested by enzymes in the small intestine.

Some foods that include these hard to digest starches include cabbage, cauliflower, beans and brand, which explains why you may feel excessively gassy after that big bowl of chili.

When those undigested carbs reached the colon in the lower intestines, bacteria take over.

The byproduct is a combination of gases that include carbon dioxide, hydrogen, methane, even hydrogen sulfide.

A stinky one.

That mix of gases plus the air that you swallowed is what makes its way through the large intestine to the Ennis, where it is expelled.

Of course, everyone has different amounts of various species of bacteria and yeasts working away in their guts.

But I'm sure you're dying to know.

So I'll just tell you.

The average human toot contains roughly 59% nitrogen, 21% hydrogen, 9% co, two 7% methane and 4% oxygen.

It's that last 1% in the form of hydrogen sulphide and other silver compounds that is the most potent in terms of producing those notorious, unpleasant rotten eggs smells.

While some of these chemicals are produced by bacteria and you're got eating sulfur rich foods like eggs and onions and beans, that doesn't help on the smelly front.

Well, now I know more than I ever needed two about the composition of farts cinq cinq.

While we're on the subject of expelling air, though, sneezing is another kind of annoying thing.

Our bodies d'oh!

And the reason might seem obvious, But expelling pathogens from our noses is only a part of the answer to why we sneeze.

As Michael explains, everyone everywhere occasionally sneezes.

It's something that humans, and even some animals, like cats and dogs and chickens just do.

But why why do we sneeze?

If your answer is that it's our noses way of getting rid of irritants and excess mucus?

You're right, but only partly.

Scientists have long thought that sneezing, technically known a stern mutation, is a reflex.

When irritants like dust, dander, germs or pollen get into your nose, your brain sends out a signal to get rid of that same signal goes out if an excessive amount of mucus is hanging out in there to say, if you have a cold, this signal triggers a deep breath, which you hold in your lungs for a moment, and while you're holding your breath, your chest muscles clench and pressure builds.

Your tongue is forced to the roof of your mouth and you breathe out fast through your nose in the form of a sneeze.

That is the old, short and still correct answer to the question.

Why do we sneak?

But according to a paper published in 2012 in the Journal facet.

There's a little more to it than that.

And it all has to do with Celia, the tiny, hair like paddles that line our noses and Sinuses.

In the study, a group of researchers from the University of Pennsylvania basically grew a tiny nose.

They took cells from the nostrils of several healthy adults and grew them in an incubator for a few weeks until the cells had formed the same type of lining that's in your Sinus, complete with silly.

Then, to mimic a sneeze, the scientist puffed air onto the lining.

They noticed that the burst of air triggered the Celia to kick into high gear, moving back and forth repeatedly for up to several minutes after the tricks need.

So why were they so active for so long?

Any potential irritants would have been cleared out already.

Well, the triggered Celia were acting as a broom, basically resetting the entire nasal environment, not just the parts where they had been irritating gun, just like computers.

Do Biologists think that our nose needs a reboot every once in a while, and it's kind of furry.

Restart button is made of all those silly, but it turns out that not everybody's sneezes actually reboot their know.

In addition to looking at Healthy People sells this same group of scientists took a peek of the cells of people suffering from sinusitis, which causes inflamed Sinuses and general nasal discomfort.

Runny nose, nasal congestion, all that stuff.

They discovered that when they puffed air onto the tissue of the sinusitis sufferers, the cilia didn't beat fast, meaning that chronic sinusitis might have to do with cilia that can't properly reset post sneeze.

And that knowledge might help researchers develop treatments for it.

Well, I hope my cilia stays healthy so my nose can stay clean with some occasional cellular sweeping.

Though all this talk about irritants and nasal cells wriggling is making my nose itch.

And actually, that's another odd thing.

Our bodies do it even when we just think about think serious Michael again to explain why that is itching.

Just thinking about it is making me kind of each image could be caused by all kinds of usual culprits are things like bug bites, poison ivy or strands of hair brushing against your skin.

But it's also brought on by skin conditions like eczema or psoriasis as well a seemingly unrelated things like brain tumors, diabetes and chemotherapy.