1. Drinking Water Helps Maintain the Balance of Body Fluids. 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 and tells it how much water to excrete as urine or hold onto for reserves,” says Guest, who is also an adjunct professor of medicine at Stanford University.
When you’re low on fluids, the braintriggers the body’s thirst mechanism. And unless you are taking medications that make you thirsty, Guest says, you should listen to those cues and get yourself a drink of water, juice, milk, coffee — anything but alcohol.
2. Water Helps Keep Skin Looking Good. 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, says Atlanta dermatologist Kenneth Ellner, MD.
“Dehydration makes your skin look more dry and wrinkled, which can be improved with proper hydration,” he says. “But once you are adequately hydrated, the kidneys take over and excrete excess fluids.”
You can also help “lock” moisture into your skin by using moisturizer, which creates a physical barrier to keep moisture in.
3. Water Helps Your Kidneys. 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, explains Guest. “Your kidneys do an amazing job of cleansing and ridding your body of toxins as long as your intake of fluids is adequate,” he says.
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.