You need water to regulate body temperature and to provide the means for nutrients to travel to your organs and tissues. Water also helps transport oxygen to your cells, removes waste and protects your joints and organs.
Dehydration
Dehydration occurs when you lose more water than you take in. You lose water through urination, respiration, and by sweating, and you lose more water when you're active than when you're sedentary.
Diuretics, such as caffeine pills, certain medications and alcohol may increase the amount of water your body loses. Lost fluids must be replaced by the fluids in the foods you eat and the beverages you drink.
Symptoms of mild dehydration include thirst, pains in joints and muscles, headaches and constipation. A strong odor to your urine, along with a yellow or amber color, may also indicate dehydration.
Note: riboflavin, a B vitamin, will make your urine bright yellow when you take dietary supplements that contain large amounts of riboflavin. Certain medications can change the color of urine, as well.