- The body is composed of 50 to 75% water - Lean muscle contains more water (73$ - Fat tissue contains less water (20%) - For a healthy person, water intake equals water outtake - For every pound of water weight lost, you should intake two cups of fluid. # Functions - Is a solvent - Is a major component of blood, saliva, sweat, tears, mucus, and joint fluid - Removes waste - Helps transport substances - Lubricates tissues - Regulates body temperature - Helps digest foods - Participates in many chemical reactions - Helps maintain proper blood pH - **Doesn't play a major role in immune system function** # Compartments - The body has two major fluid compartments: - **Intracellular water** is inside the cells - Managed by potassium and phosphorus - **Extracellular water** surrounds cells or is in the blood - managed by sodium and chloride - Water **follows** sodium # Dehydration - Common signs of dehydration: - Rapid weight loss - Dry or sticky mouth - Low or no urine output - Dark urine - No tears - Sunken eyes - If not corrected, dehydration can lead to death # Water intoxication Water intoxication is a condition that occurs when too much water is consumed in a short period of time or kidneys can't filter water from blood - Excess water dilutes sodium concentration of blood - Results in **hyponatremia** - Low blood sodium - Symptoms: confusion, dizziness, headache, can lead to death