How Much Caffeine Is Too Much?

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1. 01How Much Caffeine Is Too Much?

   Good morning, everyone. I'm a graduate student, and during exam season I used to drink coffee all day. One night, my heart was racing and I couldn't sleep at all. That made me wonder: how much caffeine is too much?

   大家早上好。我是一名研究生，以前一到考试季就整天喝咖啡。有一天晚上，我心跳得特别快，一整夜都没睡着。这让我开始思考：咖啡因喝多少才算太多？

2. 02The Official Guidance

   According to the U.S. Food and Drug Administration, four hundred milligrams a day is an amount not generally associated with negative effects for most adults. That's about two to three twelve-ounce cups of coffee.

   根据美国食品药品监督管理局，也就是FDA的说法，对大多数成年人来说，每天四百毫克通常不会带来负面影响。这大约相当于两到三杯十二盎司的咖啡。

   Source: U.S. Food and Drug Administration, "Spilling the Beans: How Much Caffeine is Too Much?"

3. 03Caffeine in Common Drinks

   Here's what surprised me. The FDA says a twelve-ounce cup of brewed coffee can contain anywhere from about one hundred thirteen to two hundred forty-seven milligrams. So two cups of strong coffee could already be over the limit.

   让我惊讶的是，FDA说，一杯十二盎司的滴滤咖啡，咖啡因含量大约在一百一十三到二百四十七毫克之间。所以，两杯浓咖啡就可能已经超过上限了。

   Source: U.S. Food and Drug Administration, "Spilling the Beans: How Much Caffeine is Too Much?"

4. 04Why the Range Is So Wide

   Why is the range so wide? Caffeine depends on the type of coffee bean, how it's brewed, and of course, the size of the cup. A large café drink can be much bigger than twelve ounces.

   为什么范围这么大呢？咖啡因的含量取决于咖啡豆的种类、冲泡方式，当然还有杯子的大小。咖啡店里的大杯饮品可能远远超过十二盎司。

5. 05Signs You've Had Too Much

   The FDA lists several signs that you may have had too much, including a fast heartbeat, trouble sleeping, feeling anxious or jittery, an upset stomach, and headaches. I had almost all of them that night.

   FDA列出了几种可能摄入过多的信号，包括心跳加快、难以入睡、感到焦虑或心神不宁、肠胃不适，以及头痛。那天晚上，这些症状我几乎全都有。

   Source: U.S. Food and Drug Administration, "Spilling the Beans: How Much Caffeine is Too Much?"

6. 06Not the Same for Everyone

   It's important to remember that this guidance isn't the same for everyone. The FDA suggests that people who are pregnant, breastfeeding, or taking certain medicines talk to a doctor, and medical experts advise against energy drinks for children and teens.

   需要记住的是，这个建议并不适用于所有人。FDA建议，怀孕、哺乳或正在服用某些药物的人要咨询医生，而且医学专家也不建议儿童和青少年喝能量饮料。

   Source: U.S. Food and Drug Administration, "Spilling the Beans: How Much Caffeine is Too Much?"

7. 07What I Do Now

   Now I keep it simple. I have two cups of coffee before noon, switch to tea in the afternoon, and keep a bottle of water on my desk while I study.

   现在我的做法很简单。中午之前喝两杯咖啡，下午改喝茶，学习的时候在桌上放一瓶水。

8. 08Conclusion

   To sum up, caffeine isn't bad, but the amount matters, and cups can be very different. Know roughly how much you're having, listen to your body, and ask a doctor if you're unsure. Thank you.

   总结一下，咖啡因并不是坏东西，但摄入量很重要，而且每一杯的差别可能很大。要大致了解自己喝了多少，倾听身体的声音，不确定的时候就问问医生。谢谢大家。