Blood, muscles, lungs, and brain all contain water. You need water to allocate body temperature and to provide the means for nutrients to travel to your organs and tissues. It also helps transport oxygen to your cells, removes waste, and protects your joints and organs. Taking in too little water or losing too much water leads to dehydration. Symptoms of mild dehydration include thirst, pains in joints and muscles, lower back pain, headaches and constipation.
A strong odor to your urine, along with a yellow or amber color, may indicate that you may not be getting enough water. Note that riboflavin, a B vitamin, will make your urine bright yellow when you take dietary supplements that contain large amounts of riboflavin. Some medications can change the color of urine as well.
You lose water through urination, respiration, and by sweating, and you lose more water when you're active than when you're stationary. Diuretics, such as caffeine pills, certain medications and alcohol may boost the amount of water your body loses. Lost fluids must be restored by the fluids in the foods you eat and the beverages you drink.
How much water do you need to drink? At least 20% of the water you need comes from the foods you eat. The rest comes from the beverages you drink. Some experts believe you can estimate the amount of water you need by taking your weight in pounds and dividing that number in half. That gives you the number of ounces you may want to drink each day. For example, if you weigh 160 pounds, you might want to drink at least eighty ounces of water or other fluids per day. Other factors include amount of physical activity and the climate where you are located. My water calculator can help you establish how much water you need to consume each day.
In all probability water is the best choice for rehydration because it's economical and has no calories or added ingredients. Sweetened soft drinks and sodas have added sugar that adds extra calories but no additional nutritional value. Sports drinks contain minerals that may help keep your electrolytes in balance, which is good for recovering after a hard work out, but look out for added sugar and calories that you may not want. Fruit and vegetable juices can be a good choice because they have vitamins and minerals your body needs (read labels, however -- vegetable juices may be high in sodium). Caffeinated beverages like tea and coffee count too, but too much caffeine can make you feel jittery.