<P> In physiology, body water is the water content of an animal body that is contained in the tissues, the blood, the bones and elsewhere . The percentages of body water contained in various fluid compartments add up to total body water (TBW). This water makes up a significant fraction of the human body, both by weight and by volume . Ensuring the right amount of body water is part of fluid balance, an aspect of homeostasis . </P> <P> By weight, the average human adult male is approximately 60% water and the average adult female is approximately 50% . There can be considerable variation in body water percentage based on a number of factors like age, health, weight, and sex . In a large study of adults of all ages and both sexes, the adult human body averaged ~ 65% water . However, this varied substantially by age, sex, and adiposity (amount of fat in body composition). The figure for water fraction by weight in this sample was found to be 58 ± 8% water for males and 48 ± 6% for females . The body water constitutes as much as 73% of the body weight of a newborn infant, whereas some obese people are as little as 45% water by weight . This is due to how fat tissue does not retain water as well as lean tissue . These statistical averages will vary with factors such as type of population, age of people sampled, number of people sampled, and methodology . So there is not, and cannot be, a figure that is exactly the same for all people, for this or any other physiological measure . </P> <P> Most of animal body water is contained in various body fluids . These include intracellular fluid; extracellular fluid; plasma; interstitial fluid; and transcellular fluid . Water is also contained inside organs, in gastrointestinal, cerebrospinal, peritoneal, and ocular fluids . Adipose tissue contains about 10% of water, while muscle tissue contains about 75% . </P> <P> In Netter's Atlas of Human Physiology, body water is broken down into the following compartments: </P>

Where is most water in the body found