你知道如何博取欢心（steal hearts），赢得人心（win hearts），偶尔也会丧失信心（lose heart）。但实际上，你对自己的心脏以及它的工作原理又有多少了解呢？尽情读下去吧！
This Valentine's Day, millions of people will exchange heart-shaped gifts of all kinds, from candy to cards. But did you know that the human heart does not actually look like the typical valentine shape?
今年的情人节，无数人会交换各式各样的心形礼物，从糖果到卡片不一而足。但你知道人类的心脏其实与典型的情人节心形不尽相同吗？
We spoke with heart specialist[专家] Robert DiBianco to learn more about this important organ.
我们与心脏科专家罗伯特·迪比安科聊了一会儿，以便更清楚地了解这个重要的器官。
According to Dr. DiBianco, the human heart is about the size of a fist.
据迪比安科医生说，人的心脏与其拳头的大小相仿。
“Because the heart is a muscle with lots of blood supplied to it, it looks red like meat,” he explained. “In people who are overweight…the heart looks yellow because it is covered with yellow fat.”
“因为心脏是一块有许多血液供应于其间的肌肉组织，所以它看起来就像肉一样鲜红，”他解释道。“而对于那些体重过重的人……他们的心脏看起来是黄色的，因为它被黄色的脂肪包裹着。”
In the United States, children are taught to place their hands over their hearts when pledging[宣誓] allegiance[效忠] to the flag. Most people have heard that the heart is on the left side of the chest. In reality, the heart is in the middle of the chest, tucked[挤进] snugly[紧贴地] between the two lungs. It's tipped[倾斜] slightly so that a part of it sticks out and taps[与……进行联接] against the left side of the chest, which is what makes it seem as though it's located there.
在美国，人们教小孩子在对旗帜宣誓效忠时，要将手按在心口上。大多数人都听说过心脏位于胸腔的左边。但事实上，心脏位于胸腔的中间，紧紧地包裹在两片肺叶之间。它略微倾斜，一部分突出在外并与左胸腔相连，这就是为什么它看起来好像位于左侧。
But what does the heart actually do?
那么，心脏实际上有什么功能呢？
DiBianco explained that the heart is a pump that pushes blood throughout the body. The heart moves blood by expanding[扩张] and contracting[收缩] (getting bigger and smaller).
迪比安科解释说，心脏就是一个泵，将血液压向身体的各个部位。心脏通过扩张和收缩（变大或缩小）来推动血液流动。
“Each living part of the body needs blood to live, that's why it's important for the blood to go to different parts of the body,” DiBianco said.
“身体的每一个部位都需要血液才能存活，所以让血液流向身体的不同部位是非常重要的，”迪比安科说。
When you're exercising, it takes your blood about ten seconds to get from your heart to your big toe and back. In fact, a kid's heart has to push blood through about 60,000 miles of blood vessels[血管]—that's long enough to circle the Earth two and a half times!
做运动的时候，你的血液从心脏流到大脚趾再返回需要大约十秒钟的时间。实际上，小孩的心脏必须推动血液流过约60000英里（96560千米）长的血管——这个长度足以围绕地球两圈半了！
All that pumping takes a lot of effort. To push blood, an average heart beats a hundred thousand times a day. That means that in a lifetime, the average human heart will beat more than two and a half billion times.
整个泵送过程相当费力。要推动血液流动，一颗普通的心脏一天要跳动十万次。这就意味着在人的一生当中，一颗普通人的心脏要跳动超过二十五亿次。
Because the heart is so important, the American Heart Association reminds people that they need to treat their hearts with care. Exercise and healthful foods can help the heart do its job.
由于心脏有着如此重要的作用，美国心脏协会提醒人们要善待自己的心脏。运动和健康的饮食都有助于心脏顺利工作。
Keep Your Heart Happy
善待你的心脏
Most kids are born with a healthy heart and it's important to keep yours in good shape[处于良好状态]. Here are some things that you can do to help keep your heart happy:
大多数孩子天生就有一颗健康的心脏，因此保持你的心脏状态良好十分重要。以下这几点可以让你的心脏保持愉快：
Remember that your heart is a muscle. If you want it to be strong, you need to exercise it. How do you do it? By being active in a way that gets you huffing[吹气] and puffing[喘息], like jumping rope, dancing, or playing basketball. Try to be active every day for at least 30 minutes! An hour would be even better for your heart!
记住，你的心脏是一块肌肉。如果你想让它强壮起来，就要对它进行锻炼。该如何锻炼呢？积极参加那些让你气喘吁吁的运动吧，譬如跳绳、跳舞或打篮球。每天尽量锻炼至少三十分钟！锻炼一个小时对你的心脏更有益！
Eat a variety of healthy foods and avoid foods high in unhealthy fats, such as saturated fats注1 and trans fats注2 (reading the labels on foods can help you figure out if your favorite snacks contain these unhealthy ingredients).
食用不同种类的健康食物，少吃富含不健康脂肪的食物，例如饱和脂肪和反式脂肪（阅读食物上面的标签能帮你分辨你最爱的零食是否含有这些不健康的成分）。
Try to eat at least five servings of fruits and vegetables each day.
每天尽量吃至少五份水果和蔬菜。
Avoid sugary soft drinks and fruit drinks.
少吃含糖的软饮和水果饮料。
Don't smoke. It can damage the heart and blood vessels.
不要抽烟，它会对心脏和血管造成损害。
So now you know that your heart doesn't look like a valentine, but it sure deserves to be loved for all the work it does. It started pumping blood before you were born and will continue pumping throughout your whole life.
现在你知道自己的心脏看上去并不像情人节心形了吧，但念及它所担当的所有工作，它当然值得好好爱护。它在你出生之前就开始泵送血液，而且还会一直工作到你的人生尽头呢。
注1：饱和脂肪是一种脂肪，最常见于动物身上，它的脂肪酸链不能容纳多余的氢原子。人们认为食物中含有过多这种脂肪会提高血液中的胆固醇含量。
注2：反式脂肪是一种不饱和脂肪酸，主要来自经过部份氢化的植物油。反式脂肪对健康并无益处，也不是人体所需要的营养素。长期摄入反式脂肪会增加罹患冠状动脉心脏病的机率。