I can be [loudly] loud.

I've been known to talk a little too fast. I really excited about nerdy things

And you're probably thinking to yourself

"Ah, that Hank, he must have to drink a bunch of Rockstar, coffee, Red Bull, Diet Coke,

other Coke and coffee and Rockstar and coffee... I already did coffee! ...to keep himself

so peppy all the time." [normal speed] And you would be wrong about that.

This machine does not require caffeine to operate!

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I have been known to have a Coke every once in a while, but in general

I tend to avoid the world's most popular psychoactive drug. This make me something

of an aberration in a world that is caffeine crazy. And by crazy

I mean that today millions have you will pay more for 12 ounces of this

then for a gallon of this. And I don't even want to talk about what happens to

my friends when they go a couple days

without the caffeine. Holy anxious, irritable, headachy people!

This stuff's powerful. Despite all the sweet tasting things that we tend to put into

caffeinated beverages caffeine itself

is a bitter, white, powdery alkaloid. So caffeine does have taste which is why

Caffeine-free Coke and Coke taste different. World consumes over 260

million pounds of caffeine every year and while most if it is extracted either

from coffee or tea, there's a bunch of different natural sources. These include two

South African plants: yerba matte and guarana, the latter

you probably have heard of as an additive in some energy drinks. And

there's also something called the kola nut, which is native to western and central

Africa, which a lot of people chew on for its stimulating properties. And once upon a

time it was used as flavoring for the popular caffeinated beverages

that still bear its name today. But since you,

my dear viewer, have an active, analytical, science-y mind, you're wondering right now

"Why is it so stimulating? How does it work?"

Basically it tricks your brain into thinking that you're not tired. Caffeine,

known to chemists as 1,3,7-trimethylxanthine,

is actually similar in structure to naturally-occurring molecules in our

in our body called adenosines.

Adenosine bonds to receptor cells in the brain, which in turn has a calming effect

[slowing] on the entire nervous system and that

makes you [slowly] sleepy. What caffeine does

is it blocks those receptors in the brain before adenosine can get in there

and do its thing.

Instead of calming the nerve cells, caffeine stimulates them

causing increases in the heart rate and the blood pressure, increasing alertness

and delaying the onset of fatigue. People who love their caffeine love that

feeling of alertness,

that artificial brain chemistry bond is creating. Caffeine peaks in your bloodstream

about 30 minutes after you first take it in,

and then it has a half-life in your body about six hours. So six hours after

you drink it, you're feeling half the effects, which is why people have to keep drinking

throughout the day in order to maintain the feeling of alertness that that

initial cup gave them. And this raises the question of whether or not caffeine

is addictive. And it sort of is but technically, it isn't. Caffeine can cause

some physical dependence but going cold turkey isn't gonna give you anything like

the withdrawal symptoms of

nicotine or cocaine. You'll have a headache, you'll be cranky,

but you'll feel better in a day or two, I promise. Caffeine may feel pretty addictive

but it's more about dedicated habit.

It doesn't mean the scientific definition of what an addictive substance is. Unlike

cocaine, scientists say, caffeine doesn't pose a threat to society and it doesn't

activate these brain reward circuits that are kinda the key to actual

physical addiction. So going back to

this friend of mine who has like two liters

of Mountain Dew a day, and he mixes it up with espresso shots... Should I be worried

about that guy actually overdosing on caffeine? The answer,

thankfully, is no. Doctors recommend that the average person keep his or her

caffeine intake below 300 milligrams per day

That's roughly the amount of caffeine in two 12-ounce cups of coffee. By comparison a

Red Bull contains about

80 milligrams of caffeine, while pills like NoDoz

contain two hundred milligrams per pill. But here's the deal:

depending on your weight, you would need to consume between six and seven grams

have caffeine per day, which would be really hard to do unless you were

dedicated to the cause and had, you know, a jar full of caffeine.

So unless my friend can slam fifty to a hundred cups of coffee in the day

which I don't think anyone's stomach could actually be big enough to handle,

he'll be okay. So good news: we can all stop being so nervous.

And just relax a little bit. Thank you for watching this episode of SciShow

I'm gonna have a Coke now. If you I wanna learn more about caffeine, there's links in the description.

If you wanna ask questions or suggest topics you can hook up with us on Facebook or Twitter

or of course

in the YouTube comments below.

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