作为一个酷爱喝水的人，也知道其实大多数建议多喝的并不只是白水，还有淡盐水、柠檬水……不管怎么说，每天要喝八杯水的说法估计和“an apple a day keeps the doctor away”一样会具有持久的生命力。但所谓八杯水只是一个平均的概念，每个人的情况不同，可能需要更少或更多的水。有个便捷的方法可以观察到你的饮水量是否达标——尿液的颜色。
If your urine is clear or very pale, congrats—you have good hydration. But if it’s a brighter yellow or amber color, you should probably be downing more water.
这里给大家找到了更直观的图示：
图中1、2、3都是饮用了足够身体所需水量的状态。要注意的是，服用了某些维生素补充剂也有可能会改变尿液颜色，就不适合此对照表了。
喝足了身体所需水分后，你的身体会有以下九个变化。
1. 能帮助你应对健身中的剧烈运动
Muscles need a good balance of electrolytes like sodium, potassium[pəˈtæsiəm], and magnesium[mæg'niːzɪəm] to function properly. Without proper hydration, electrolytes can’t exchange as easily, and the muscles can lose plumpness and be more prone to cramping.
肌肉有良好的电解质平衡，有助于钠离子，钾离子和镁离子正常工作。 如果没有适当的补水，电解质不能轻易交换，肌肉会失去丰满度，更容易发生痉挛。
* electrolyte/ɪ'lektrəlaɪt/: n. a liquid containing ions that electricity can pass through 电解质
2. 能使肾脏功能得到更好发挥
肾脏通过液体的形式帮助身体清除废物；如果没有足够的水，就很难让肾脏发挥它的排污功能。
Plus, without needing regular bathroom visits, a hard mineral could form and cause kidney stones.
而且，如果没有进行有规律的入厕，可能会导致硬质矿物堆积而最终发展为肾结石(我有个朋友正是长期不爱喝水，冷不丁就肾结石了，自此每天不敢不喝水)。
3. 水也可以成为你的能量棒
Your body needs water to keep up its energy levels, which is why you might feel sluggish if you aren’t drinking enough water every day. Some people turn to caffeine because they think they’re always tired, but something like caffeine won’t necessarily have beneficial effects on energy levels if they’re not hydrated as well.
身体也需要水来维持能量。可能有些时候会觉得身体懒懒的，也许正是一种缺水的表现。这个时候应该及时补水而不是去找咖啡来喝。
* sluggish: adj. not performing or reacting as quickly as usual
e.g. She woke up feeling tired and sluggish.
4. 能容光焕发
When your skin cells aren’t getting the water they need, they’ll start to wither and shrink. But if you drink enough water, your skin will look more lustrous and get plumpness that erases fine lines that form when you’re dehydrated.
补充水分不会让你从五十岁变回二十岁，那是魔法。但是适当的水分可以让细胞饱满，肌肤也会有光泽。
* lustrous: adj. bright and shiny
5. 能使身体运作更有规律
When your body needs to have more water in a certain area, it will take out of less essential areas—and that means it will take away from your digestive system. But by staying hydrated, you can avoid constipation.
当身体内一些重要的环节需要水分，而你没有足够地提供时，身体会想办法从别的地方挪用——比如消化系统——容易导致便秘。
* constipation: n. a condition in which you cannot move solid waste out of your body easily
6. 能帮助排除病菌
Your body has to ramp up to launch an attack against the germs when you’re sick, which means your cells need more calories and fluids to keep up with the demands. For instance, you’re losing fluids when your nose starts to run in your body’s attempt to flush out pathogens.
多喝水能让疾病更快痊愈。身体内部的防御机制会自发与病菌战斗，这些战斗需要能量和液体来实现。就像流鼻涕也是一种排除病菌的运作一样。
* ramp up: to increase sth such as a rate or level
* pathogen/'pæθədʒ(ə)n/ : sth such as bacteria or a virus that causes disease
7. 能减少头痛
When your body doesn’t have the fluids it needs, it can’t transfer important nutrients as easily, and a headache is your warning sign. It’s your body’s way of signaling that something is amiss.
头痛有时也是一种信号，告诉你有某些地方营养不足，需要依靠水分来运输。
* amiss: adj. [never before noun] likely to cause difficulties or problems
e.g. I was convinced that something was amiss.
8. 能排更多的汗
If you haven’t been drinking enough water, you might not create that cooling sweat during an intense workout. If you’re doing vigorous activity and weren’t sweating when you knew you would be, that’s a sign to seek rehydration. It could be a red flag for heat stroke or heat exhaustion.
排汗虽然不算件舒服的事，却是件好事。排汗是在帮助身体维持正常的体温。如果剧烈运动是，或者身处过热的地方但没能排出足够的汗液，就可能会中暑。
9. 能减轻心脏负担
If you aren’t drinking enough water, your heart can’t pump blood as efficiently, raising your heart rate and decreasing blood pressure. If you’re not adequately hydrated, you’re putting additional strain on the heart.
同肌肉一样，心脏也需要足够的水分来辅助运作。水分不足的话，会给心脏造成额外的压力。
p.s. 也别喝多了……