We all know that we need water to stay alive, but we may not be aware just what water does for our bodies. It dissolves nutrients and minerals, and it helps to move them around our bodies. Human blood is more than 80 percent water. Water flushes waste products out of our kidneys and livers, lubricates our joints and keeps our eyes, mouths and nose tissues moist. It regulates human body temperature and protects our internal organs. Our lungs are 90 percent water and our brains are 70 percent water. In fact, about 60 percent of the average human body is water.
To support this water-based system, the average person needs to consume about 8 cups of water a day. The human body loses more than 1 cup (237 milliliters) of water each day just in the vapor exhaled from the lungs, and the body sends another 6 cups (1.4 liters) down the toilet every day. Some 20 percent of your liquid needs can come from solid foods - - although this depends entirely on the food you eat, because some foods, like watermelons, are made almost entirely of water. You need to receive the rest of your daily hydration by drinking water and water-based beverages.
If you notice that your urine is dark yellow, or if you feel other symptoms of mild dehydration (dryness of the mouth, headaches or dizziness), you probably need more water. You will need to increase your water intake when you exercise, when you're in a hot climate and when you have diarrhea or fever. Your liquid needs can be met by many kinds of drinks, but remember that some drinks, such as alcoholic beverages, can worsen dehydration. Not having enough water in your system can start out as simply uncomfortable, but if it continues, it can be fatal. The first sign of dehydration is thirst: If you feel thirsty, you should drink water. Severe dehydration can make your pulse weak and cause rapid breathing, convulsions, loose skin and sunken eyes. Untreated dehydration can eventually lead to heart failure and death.
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