如果你不喝水，身体会发生什么？
What would happen if you didn't drink water?
词汇：考研 | 句法：六级| 文本：考研
刘立军供稿
Water is virtually everywhere, from soil moisture and ice caps, to the cells inside our own bodies. Depending on factors like location, fat index, age, and sex, the average human is between 55-60% water. At birth, human babies are even wetter. Being 75% water, they are swimmingly similar to fish. But their water composition drops to 65% by their first birthday. So what role does water play in our bodies, and how much do we actually need to drink to stay healthy?
从湿润的土壤和冰盖，再到我们体内的细胞，水几乎无处不在。根据地点、脂肪指数、年龄和性别等因素的不同，普通人体内的水分占比在55%-60%之间。婴儿出生时含水量更高，达到75%，这使得他们与鱼类非常相似。但到了婴儿一岁生日时，这一比例会下降到65%。那么，水在我们的身体中扮演了什么角色？为了保持健康，我们实际需要的饮水量是多少呢？
The H2O in our bodies works to cushion and lubricate joints, regulate temperature, and to nourish the brain and spinal cord.
我们体内的水分起到缓冲及润滑关节、调节体温以及滋养大脑和脊髓的作用。
Water isn’t only in our blood. An adult's brain and heart are almost three quarters water. That's roughly equivalent to the amount of moisture in a banana. Lungs are more similar to an apple at 83%. And even seemingly dry human bones are 31% water. If we are essentially made of water, and surrounded by water, why do we still need to drink so much?
水不仅仅只存在于我们的血液中。成年人大脑和心脏的四分之三几乎是水，这大约相当于一根香蕉中的含水量。肺部的含水量更接近苹果，为83%。甚至看似干燥的人体骨骼，也含有31%的水分。如果我们的身体本质上是由水构成，并且我们生活在被水包围的环境中，为什么还需要喝这么多水呢？
Well, each day we lose two to three liters through our sweat, urine, and bowel movements, and even just from breathing. While these functions are essential to our survival, we need to compensate for the fluid loss. Maintaining a balanced water level is essential to avoid dehydration or over-hydration, both of which can have devastating effects on overall health.
其实，我们每天通过汗液、尿液、排便，甚至仅仅是呼吸，就会失去两到三升的水分。但由于这些功能对我们的生存至关重要，我们必须补偿其中流失的水分。维持体内的水平衡对于避免脱水或过度水合至关重要，因为这两种情况都会对整体健康状况产生毁灭性的影响。
At first detection of low water levels, sensory receptors in the brain’s hypothalamus signal the release of antidiuretic hormone. When it reached the kidneys, it creates aquaporins, special channels that enable blood to absorb and retain more water, leading to concentrated, dark urine. Increased dehydration can cause notable drops in energy, mood, skin moisture, and blood pressure, as well as signs of cognitive impairment. A dehydrated brain works harder to accomplish the same amount as a normal brain, and it even temporarily shrinks because of its lack of water.
当检测到体内水分水平降低时，大脑下丘脑中的感觉受体会发出信号，释放抗利尿激素。这种激素到达肾脏后，会生成特殊的通道——水孔蛋白，使血液能够吸收并保留更多水分，从而导致尿液浓缩，且颜色变深。脱水加剧会导致能量、情绪、皮肤湿度和血压显著下降，还可能出现认知功能受损的迹象。脱水的大脑为了完成与正常大脑相同的工作量，需要付出更多努力，甚至会因为缺水而暂时缩小。
Over-hydration, or hyponatremia, is usually caused by overconsumption of water in a short amount of time. Athletes are often the victims of over-hydration because of complications in regulating water levels in extreme physical conditions. Whereas the dehydrated brain amps up the production of antidiuretic hormone, the over-hydrated brain slows, or even stops, releasing it into the blood. Sodium electrolytes in the body become diluted, causing cells to swell. In severe cases, the kidneys can't keep up with the resulting volumes of dilute urine. Water intoxication then occurs, possibly causing headache, vomiting, and, in rare instances, seizures or death. But that's a pretty extreme situation.
过度水合（或低钠血症）通常是短时间内过量饮水造成的。运动员由于极端体能条件下难以调节水分平衡，常常成为过度水合的受害者。脱水的大脑会加速抗利尿激素的生产，而过度水合的大脑则会减缓甚至停止将其释放到血液中。体内的钠电解质被稀释，导致细胞肿胀。在严重情况下，肾脏无法处理大量稀释的尿液，从而引发水中毒，可能导致头痛、呕吐等现象，在极少数情况下，甚至引发癫痫发作或死亡。但这是相当极端的情况。
On a normal, day-to-day basis, maintaining a well-hydrated system is easy to manage for those of us fortunate enough to have access to clean drinking water. For a long time, conventional wisdom said that we should drink eight glasses a day. That estimate has since been fine-tuned. Now, the consensus is that the amount of water we need to imbibe depends largely on our weight and environment. The recommended daily intake varies from between 2.5-3.7 liters of water for men, and about 2-2.7 liters for women, a range that is pushed up or down if we are healthy, active, old, or overheating.
在日常生活中，对于我们这些有幸可以喝到干净饮用水的人来说，保持身体水分充足并不难。长期以来，传统观念认为我们应该每天喝八杯水。这个估算后来得到了进一步细化。现在普遍认为，我们需要摄入的水量主要取决于体重和环境。男性建议每日摄入量为2.5至3.7升，女性约为2至2.7升，具体范围会因健康状况、是否活跃、年龄大小或是否处于高温环境而有所调整。
While water is the healthiest hydrator, other beverages, even those with caffeine like coffee or tea, replenish fluids as well. And water within food makes up about a fifth of our daily H2O intake. Fruits and vegetables like strawberries, cucumbers, and even broccoli are over 90% water, and can supplement liquid intake while providing valuable nutrients and fiber.
虽然水是最健康的补水来源，但含咖啡因的咖啡或茶等饮品，也能补充水分。食物中的水分约占我们每日水分摄入量的五分之一。像草莓、黄瓜甚至西兰花这样的水果和蔬菜含水量超过90%，可以在补充液体的同时，提供宝贵的营养素和膳食纤维。
Drinking well might also have various long-term benefits. Studies have shown that optimal hydration can lower the chance of stroke, help manage diabetes, and potentially reduce the risk of certain types of cancer. No matter what, getting the right amount of liquid makes a world of difference in how you'll feel, think, and function day to day.
充分饮水还可能带来多种长期益处。研究表明，保持最佳水分摄入可以降低中风的风险，帮助控制糖尿病，并可能减少某些类型癌症的风险。无论如何，摄入适量的水分对你日常的感官、思维和身体机能都会产生巨大的影响。
【词汇】
1. swimmingly adv. 顺顺当当地
2. cushion v. 缓冲，减轻冲击
3. lubricate v. 润滑
4. spinal cord n. 脊髓
5. dehydration n. 脱水
6. over-hydration n. 过度补水，水中毒
7. hypothalamus n. 下丘脑
8. antidiuretic hormone (ADH) n. 抗利尿激素
9. aquaporin n. 水通道蛋白，水孔蛋白
10. dehydrated adj. 脱水的
11. hyponatremia n. 低钠血症
12. amp up v. 增强，提高
13. sodium electrolyte n. 钠电解质
14. imbibe v. 饮，喝；吸收
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