咖啡因

字幕原文

Feeling tired? 感觉累了吗？

A little caffeine might be just the thing. 一点咖啡因可能正是你需要的。

It's in coffee and tea, in colas and many soft drinks, even in chocolate. 它存在于咖啡、茶、可乐和许多软饮料中，甚至巧克力里也有。

People love it because it gives them a boost — 人们喜欢它，因为它能提神——

it makes them feel awake 让人感觉清醒

and alive. 充满活力。

But caffeine has two sides. 但咖啡因有两面性。

Because it keeps you awake, drinking it late in the day can wreck your sleep. 因为它能让你保持清醒，所以晚上喝它会影响你的睡眠。

And too much can speed up your heart, 过量摄入还会使心跳加速，

raise your blood pressure, 升高血压，

and leave you jumpy, nervous, 让你感到紧张不安，

or aching with a headache. 甚至头痛。

Some people rely on it to get through a night shift. 有些人依靠它来熬夜上夜班。

But doctors warn: caffeine can borrow energy, but it cannot replace sleep. 但医生警告：咖啡因可以借用能量，但不能代替睡眠。

That's the catch with caffeine. 这就是咖啡因的症结所在。

It doesn't really give you energy — it only lends it to you. 它并不能真正给你能量——它只是暂时借给你。

And sooner or later, your body asks for it back. 而迟早，你的身体会要求它还回来。