Your body is composed of about 60% water. The functions of these bodily fluids include digestion, absorption, circulation, creation of saliva, transportation of nutrients, and maintenance of body temperature. "Through the posterior pituitary gland, your brain communicates with your kidneys.

For years, dieters have been drinking lots of water as a weight loss strategy. While water doesn't have any magical effect on weight loss, substituting it for higher calorie beverages can certainly help.

Cells that don't maintain their balance of fluids and electrolytes shrivel, which can result in muscle fatigue. "When muscle cells don't have adequate fluids, they don't work as well and performance can suffer. Drinking enough fluids is important when exercising for fluid intake before and during physical activity. These guidelines recommend that people drink about 17 ounces of fluid about two hours before exercise. During exercise, they recommend that people start drinking fluids early, and drink them at regular intervals to replace fluids lost by sweating.

Your skin contains plenty of water, and functions as a protective barrier to prevent excess fluid loss. But don't expect over-hydration to erase wrinkles or fine lines.

Body fluids transport waste products in and out of cells. The main toxin in the body is blood urea nitrogen, a water-soluble waste that is able to pass through the kidneys to be excreted in the urine. "Your kidneys do an amazing job of cleansing and ridding your body of toxins as long as your intake of fluids is adequate. When you're getting enough fluids, urine flows freely, is light in color and free of odor. When your body is not getting enough fluids, urine concentration, color, and odor increases because the kidneys trap extra fluid for bodily functions. If you chronically drink too little, you may be at higher risk for kidney stones, especially in warm climates.

Adequate hydration keeps things flowing along your gastrointestinal tract and prevents constipation. When you don't get enough fluid, the colon pulls water from stools to maintain hydration -- and the result is constipation. "Adequate fluid and fiber is the perfect combination, because the fluid pumps up the fiber and acts like a broom to keep your bowel functioning properly.