Patent ID: 7340295

Claim:
A method of estimating muscle mass, comprising steps of: calculating an impedance of intracellular water of a subject; and estimating a muscle mass of the subject, based on the impedance of intracellular water; wherein said step of estimating a muscle mass of the subject further includes the sub-steps of acquiring personal data including height, body weight and age of the subject, and calculating muscle mass of the subject according to a predetermined estimation formula using the acquired personal data and the impedance of intracellular water as variables; wherein said predetermined estimation formula is expressed as follows: MM =( a*H 2 )/Z ICW +b*W++c*A+d wherein MM is the muscle mass of the subject; H is the height of the subject; W is the body weight of the subject; A is the age of the subject; and a, b, c, d are constants; wherein said step of calculating impedance of intracellular water of a subject further includes sub-steps of: measuring impedance of extracellular water of the subject by applying between predetermined parts of the subject an alternating current at a sufficiently low frequency that the current only flows outside a cell membrane of the subject; measuring impedance of total body water of the subject by applying between the predetermined parts of the subject an alternating current at sufficiently high frequency that the current flows both outside and inside the cell membrane of the subject; and deriving the impedance of intracellular water of the subject by calculating an inverse of the result of subtracting an inverse of the measured impedance of extracellular water from an inverse of the measured impedance of total body water.