Apparatus and method for measuring body composition

A body composition analyzer for determining the total body water content of a subject, comprising:

• a mounting structure;
• first and second pairs of electrodes, said pairs of electrodes being mounted on opposite lateral sides of said mounting structure, and disposed for simultaneous gripping of both pairs of the electrodes by a subject;
• means for supplying a high frequency alternating current signal across one of said first pair of electrodes and one of said second pair of electrodes, so that said signal passes through the body of the subject;
• means for measuring the impedance of the body of the subject across the second of said first pair of electrodes and the second of said second pair of electrodes, and for providing an impedance signal responsive thereto;
• and
• a controller for receiving input information including at least the height, weight, gender, and general physical condition of the subject, and for processing said impedance signal responsive to said input information to determine the total body water content of the subject;
• and
• wherein said controller processes said impedance signal to determine total body water content for a particular subject by selecting a set of coefficients from a group of sets of coefficients, each set of coefficients representing the result of a regression analysis performed on the body density-impedance relationship of a particular population segment, and the particular set of coefficients selected with respect to a particular subject being selected in response to said input information including at least the height, gender, and physical condition of the subject.

In combination, an exercise apparatus whereby a subject may perform a specific biomechanical exercise, and a body composition analyzer for determining the total body water content of a subject, said body composition analyzer comprising:

• a mounting structure;
• first and second pairs of electrodes, said pairs of electrodes being mounted on opposite lateral sides of said mounting structure, and being disposed for simultaneous gripping of both pairs of the electrodes by a subject;
• means for supplying a high frequency alternating current signal across one of said first pair of electrodes and one of said second pair of electrodes, so that said signal passes through the body of the subject;
• means for measuring the impedance of the body of the subject across the second of said first pair of electrodes and the second of said second pair of electrodes, and for providing an impedance signal responsive thereto;
• and
• a controller for receiving input information including at least the height, weight, gender, and general physical condition of the subject, and for processing said impedance signal responsive to said input information to determine the total body water content of the subject;
• and
• wherein said controller processes said impedance signal to determine body fat content for a particular subject by selecting a set of coefficients from a group of sets of coefficients, each set of coefficients representing the result of a regression analysis performed on the body density-impedance relationship of a particular population segment, and the particular set of coefficients selected with respect to a particular subject being selected in response to said input information including at least the height, gender, and general physical condition of the subject;
• and wherein
• said body composition analyzer is mounted by said mounting structure to said exercise apparatus such that a subject may conveniently grasp said pairs of electrodes while performing exercises according to the function of the exercise apparatus.

A body composition analyzer for measuring the total body water content of a subject, said body composition analyzer comprising:

• a housing for containing components of said body composition analyzer;
• first and second pairs of electrodes, said pairs of electrodes being mounted on opposite lateral sides of said housing, and being disposed for simultaneous gripping of both pairs of the electrodes by a subject;
• means for supplying a high frequency alternating current signal across one of said first pair of electrodes and one of said second pair of electrodes, so that said signal passes through the body of the subject;
• means for measuring the impedance of the body of the subject across the second of said first pair of electrodes and the second of said second pair of electrodes, and for providing an impedance signal responsive thereto;
• and
• a controller for receiving input information including at least the height, weight, gender, and general physical condition of the subject, and for processing said impedance signal responsive to said input information to determine the total body water content of the subject;
• and
• wherein said controller processes said impedance signal to determine total body water content for a particular subject by selecting a set of coefficients from a group of sets of coefficients, each set of coefficients representing the result of a regression analysis performed on the body density-impedance relationship of a particular population segment, and the particular set of coefficients selected with respect to a particular subject being selected in response to said input information including at least the height, gender, and physical condition of the subject, and wherein the regression coefficients corresponding to the physical condition of the subject are selected responsive to identification of the subject as a member of one of four population segments identified as the obese, persons of normal general physical condition of the subject, athletes, and body builders.

A method for estimating total body water content of the body of a subject, comprising the steps of:

• 1) providing a controller for:
• a) accepting input data for categorizing the subject according to the parameters of gender, age, and general physical condition;
• b) accepting input data descriptive of the subject's height and weight;
• 2) transmitting a high frequency alternating current signal into the body of the subject at first spaced contact points;
• 3) measuring the impedance of the body of the subject responsive to said current signal between second spaced contact points on the body of the subject;
• and
• 4) employing said controller to calculate the total body water content of the subject according to the equation:
• TBW=(C1*H2/Z)+(C2*(Wt−cw))+C3;
• wherein:
• TBW is Total Body Water;
• C1, C2 and C3 are coefficients selected responsive to said input data concerning the gender, age, and physical condition of the subject;
• Wt is the Weight of the subject;
• cw is an estimated value of clothing weight;
• H is the Height of said subject;
• and
• Z is said measured impedance;
• and
• wherein said coefficients are selected from sets of coefficients developed by regression analysis of comparison of prior body composition measurement results, said prior body composition measurement results having been obtained by hydrostatic weighing or other accepted total body water measurement techniques performed with respect to populations parametrized according to gender, age, and physical condition of the members of the populations, with impedance measurements of the total body water content of said members.