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  • Caffeine a legal stimulant that most of us are pretty familiar with, many of us use every day,

  • and some of us are addicted to. If you are a caffeine user, you probably know your limits.

  • For me one small cup of coffee in the morning can help keep me alert and focused, whereas

  • two small cups of coffee in the morning can turn me into a cat on catnip.

  • Well for the purposes of this video and to best demonstrate the physical and mental effects of caffeine,

  • I'm going to get

  • very very caffeinated very very fast.

  • For science.

  • Go big or go home.

  • Caffeine is a stimulant drug that acts on your central nervous system.

  • Because caffeine is both lipid and water soluble

  • it can easily pass through the blood-brain barrier and act on the interior of your brain

  • Once there, caffeine works by diminishing the effect of a neurotransmitter called adenosine.

  • Adenosine acts as a suppressor for your nervous system,

  • reducing neural activity and slowing everything down.

  • Caffeine and adenosine have similar shapes so caffeine can bind to

  • the same neuroreceptors that adenosine does.

  • But because caffeine is not adenosine, it doesn't turn these neuroreceptors on.

  • This is called competitive inhibition.

  • Caffeine competes with adenosine to bind with the same receptors,

  • And because caffeine is bound, adenosine cannot bind and its effects are inhibited.

  • Long story short,

  • caffeine prevents adenosine from slowing down your nervous system.

  • So this explain part of why you feel more awake, alert and active with caffeine flowing through your veins.

  • But adenosine inhibition isn't the only thing that caffeine does.

  • Oh no.

  • Caffeine also stimulates the production of adrenaline or epinephrine.

  • Adrenaline is a pretty well known hormone involved in the fight-or-flight response.

  • It causes all sort of physiological reactions! It increases your heart rate,

  • increases the blood flow to your muscles,

  • opens up your airways, causes your blood pressure to rise, and also causes you're

  • your liver to release extra sugar into your blood stream for an added boost of energy.

  • It also causes your muscle to tighten up,

  • which would be useful if you were the lone human on the savannah,

  • deciding or not to fight or flee from that lion over the distance,

  • But as a modern twenty something sitting in from of my camera, it just give me the jitters.

  • Finally caffeine also plays with the dopamine levels in your brain.

  • Awesome, yeah.

  • Caffeine increases the amount of dopamine present in your brain by slowing down its reabsorption,

  • Much in the same way that cocaine increases the amount of dopamine present

  • by slowing down how quickly it can be sucked back into your brain tissue.

  • This means that caffeine also makes you feel good and this interaction with dopamine is how you can actually

  • build a caffeine addiction. So now you're a happy,

  • jittery, fight or flight ready bundle caffeine! Now what?

  • Well the now what really depends on how your specific body metabolizes caffeine.

  • The average half-life of caffeine in the human body is about six hours.

  • so this means that if you have two hundred milligrams of caffeine in your average cup of coffee at 9am in the morning,

  • then 6 hours later half of that will be left, so at 3pm

  • you will have a hundred milligrams of caffeine left, and then another 6 hours later you will have half of the hundred

  • you will have half of the hundred so you will have 50 milligrams of caffeine left at 9 o'clock at night.

  • But dude, who stops at just one cup of coffee?

  • Not this chick. So how much caffeine is too much caffeine?

  • A lethal dose of caffeine is about two hundred milligrams per kilogram

  • so it would take about nine thousand five hundred milligrams of caffeine to kill me.

  • Now, there are about two hundred milligrams of caffeine in a standard cup of coffee,

  • so that's about forty eight cups of coffee,

  • which is a surprisingly low number, but I would have to drink

  • all 48 of those before my body started to metabolize the caffeine,

  • which means I would literally have to chug 48 cups of coffee.

  • I literally wouldn't be able to drink that much coffee,

  • both because my stomach couldn't hold that volume of liquid and also because as every coffee drinker knows,

  • caffeine is a diuretic.

  • before I got to cup forty anyways, the stimulant effect of caffeine would be

  • jacked up so high that that the alertness and awakeness would be transformed into mania,

  • disorientation and hallucinations... great!

  • What would eventually kill you would be ventricular fibrillation, which basically means

  • that your heart would caffeine jitter itself to death.

  • So moral of the story, caffeine is a drug. It is a stimulant that has some pretty noticeable effects on your body,

  • can cause addiction, and, in high enough doses, can kill you.

  • So caffeinate wisely!

  • Go forth, do science!

  • My hand is actually not shaking too bad right now.

  • Don't try this at home, I know a lot of people do drink that much caffeine all on one day and

  • sometimes I approach it,

  • but I certainly don't do it over the span of 20 minutes.

  • I actually don't feel as terrible as I thought I would have after that amount, but I certainly don't feel good either.

Caffeine a legal stimulant that most of us are pretty familiar with, many of us use every day,

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B2 caffeine adenosine stimulant cup dopamine slowing

Caffeine!! - Bite Sci-zed

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    VoiceTube posted on 2013/03/19
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