Body Cell Mass

The body cell mass of a person is the total mass of all the cellular elements in the body that constitute the metabolically active tissue in the body. Unlike the weight of a person, this does not include parts of the body that are not active and that result in a depletion of the body cell mass over time, such as with the wasting of the body that takes place when a person is suffering from chronic conditions such as terminal cancer or AIDS.

To calculate the body cell mass, one includes in the measurement all the organ and muscle tissue, the intracellular and extracellular water, and the bone tissue. Although the purpose is often to obtain the overall body cell mass, it is usually just as important to get the relative percentages of each part of the body. For most well-nourished people, the muscle tissue is expected to account for approximately 60 percent of the body cell mass, with organ tissue accounting for another 20 percent, and the remainder made up of red cells and tissue cells. The body cell mass is expected to contain between 98 and 99 percent of all the body's potassium.

Generally, the method used for working out whether the body cell mass has been depleted is by using bioelectrical impedance analysis, which can be performed by many medical doctors. It does not involve any X-rays—in fact, there is no recourse to radia-tion—and it can get highly accurate results. The figures obtained by the bioelectrical impedance analysis are then combined with other body statistics such as sex, age, height, and weight, which are then used to calculate the body cell mass and obtain further figures that can be used to assess the health or otherwise of the person under observation.