百科知识视频之煎蛋小学堂14 当大脑“嗑”了咖啡

With it's stimulating effects,it's easy to undersand.why coffee is the second most traded commodity on Earth after oil.For many,it keeps us awake and moving through our busy days.

咖啡的刺激效果使我们容易理解，为何咖啡是仅次于油的世界第二大交易商品。它有助于保持清醒 帮我们挺过忙碌的日子。

But how does it work?What exactly does coffee do to your brain?Whenever you're awake,a chemical called adenosine slowly accumulates in your brain.And this adenosine binds to receptors which slow down brain activity-ultimately,the more adenosine there is,the more tired your brain feels.Which makes sense,as the longer you're awake,the more fatigued you become.

不过 它是怎么做到的?咖啡对大脑做了什么?当你清醒时 腺甘酸会在大脑内部逐渐积聚。腺甘酸会与减缓脑部活动的受体结合，最终 腺甘酸越多 你的大脑越累。这也有它的道理 清醒的时间越长 你也会越疲惫。

Conversely,while you sleep,the concentration of adenosine declines,gradually promoting wakefulness.But it turns out that the caffeine in your coffee is incredibly similar to adenosine in structure.The caffeine works it's way through your blookstream and into the brain.where it starts to compete and binds with adenosine receptors.

相反 当你睡眠时 腺甘酸的浓度下降，逐渐使你清醒。不过 咖啡中的咖啡因在结构上和腺甘酸很相似。咖啡因随着血液流动 进入大脑，它在此参与竞争 与腺甘酸受体结合。

But because it's not adenosine,the"sleepiness" effect isn't felt.Adenosine can no longer bind,meaning it's calming properties are diminished.Which is great for you when you're feeling tired!However,with long term use of caffeine,your brain responds by creating more adenosine receptors-which means more caffeine is required to elicit the same response.

由于它本非腺甘酸 因此人不会有倦意。腺甘酸不再被结合 其镇定作用就会减弱。当你感觉疲惫时 这正合你意!但是 长期使用咖啡以后，你的大脑会因而产生更多的腺甘酸受体.

It also means that when you try to quit drinking coffee or miss your daily intake.you might experience some with drawal symptoms and feel more tired than you would have before you ever drank coffee!But the caffeine doesn't stop there!It also stimulates the production of adrenaline-you know,the Fight or Flight hormone?This increases your heart rate,gets your blood pumping and even opens up your airways.

这也说明 当你想戒除咖啡或忘记喝时，就可能会经历某些断瘾症状，感觉比未开始喝咖啡前疲倦的多，不过 咖啡因的作用不止于此!它也会促进肾上腺素分泌，对 就是“或打或逃”的荷尔蒙?它可导致心跳加速 血流加快，甚至使导气管扩张。

Furthermore,it affects Dopamine levels by preventing its reabsorption in the brain.which makes you feel happy!In fact this is the exact same thing that cocaine does,just to a lesser degree,it's a drug,after all!This dopamine stimulation is also the aspect of coffee that makes it moderately addictive.

此外 它也会通过阻止大脑重吸收多巴胺来影响其水平，使你更欢脱!其实 咖啡因也起着同样的作用 只是程度较轻。毕竟 它还是药物!多巴胺刺激也使咖啡具有一定的成瘾性。

So can you drink too much coffee? It turns out there is a lethal dose of caffeine which is somewhere around 150mg of caffeine per kilogram of your body.This means if you weigh 70kg you would require 14,000mg of caffeine to overdose.Put into perspective an average cup of coffee contains roughly 150mg of caffeine.meaning if you are 70kg,approximately 70 cups of coffee would kill you.However,you'd have to drink those cups all at once. making it effectively impossible to overdose on caffeine from coffee.since you wouldn't be able to physically fit that much in your stomach.

那么 喝咖啡可能过量吗?其实 咖啡因存在致死剂量，大约为每千克体重150毫克咖啡因。也就是说 如果你体重70千克 则需要14克咖啡因才会过量。形象点说 平均每杯咖啡含量有150毫克咖啡因。若你的体重为70千克 喝下70杯咖啡会致死。但是 你得一次喝下这么多咖啡，单单喝咖啡导致咖啡因过量几乎不可能，因为你根本无法将这么多东西装进胃里。

You'd also start experiencing mania and hallucinations before getting to this point.Caffeine also has a halflife of around 6 hours-so if you drank a standard coffee with around 150mg of caffeine,after about 6 hours there will only be 75mg left in your system and you'll be feeling half of he effect.

在过量前 你也会出现狂躁和幻觉。咖啡的半排出期约为6小时，所以若你喝下的咖啡含有150毫克咖啡因，约6小时后 你的体内只剩下75毫克咖啡因，你感受到的效果也会减半。

And 6 hours after that,you'll have 37.5mg-Leaving more room for adenosine to jump back into action.Which is why you may reach for another cup throughout the day to maintain that glorious,alert and energetic feeling.

再过6小时 体内就仅有37.5毫克，使得腺甘酸有机可乘。这就是为何一天内 你一杯接着一杯地喝。才能保持光彩 警觉 精力十足。

So drink up!And enjoy the buzz while it lasts:)

那么喝杯咖啡吧 在作用尚存时好好享受