The observation of the conditions above is the only way to ensure an accurate result of the BIA, and that it will not be affected by the changes in the level of hydration of the person.

In normal conditions, the total amount of water in the body is 55-65% of their total weight, according to the physical condition of the person, their sex and their level of hydration. The BIA measuring method does not measure the percentage of water in the body, but this percentage affects the impedance and therefore the percentage of body fat can be determined.