how much water is in the human body

The human body is composed of a significant amount of water, generally around 60-65% of an adult's body weight. For example, an average adult male, weighing about 70 kilograms, contains roughly 42 liters of water. This amount can vary depending on factors such as age, sex, body composition, and hydration levels. Women tend to have a slightly lower percentage of body water (around 55-60%) due to a higher proportion of fat tissue, which contains less water than muscle. Newborn babies have an even higher percentage, approximately 75-78% water by weight. Water is not evenly distributed throughout the body; different organs and tissues have varying water content. For instance, the lungs and blood have about 78-79% water, the brain about 76%, smooth muscles around 75%, bones about 22.5%, and fat tissue only about 10% water. This substantial water content is vital for bodily functions including cellular processes, temperature regulation, waste removal, and lubrication of joints. On average, the human body loses about 2.4 liters of water daily, which must be replenished to maintain health and function.