Method and apparatus for measuring body fat

• US RE37,954 E1
• Filed: 03/15/1999
• Issued: 01/07/2003
• Est. Priority Date: 09/23/1992
• Status: Expired due to Term

• Current Assignee: Tanita Corporation (Tanita)
• Original Assignee: Tanita Corporation (Tanita)
• Inventors: Fukuda, Yoshinori, Sato, Hitoshi, Sato, Tomio, Oguma, Koji
• Primary Examiner(s): Hindenburg, Max
• Application Number:
  US09/268,623
• Time in Patent Office: 1,394 Days
• Field of Search: 600/300, 600/506, 600/547, 600/554, 600/587, 600/592, 600/595, 600/372, 600/382, 600/384, 177/4, 177/245, 364/413.01, 364/413.02
• US Class Current: 600/547
• CPC Class Codes: A61B 5/0537 Measuring body composition by impedance, e.g. tissue hydration or fat content
• CPC Class Codes: A61B 5/1075 for measuring dimensions by non-invasive methods, e.g. for determining thickness of tissue layer A61B8/0858 takes precedence
• CPC Class Codes: A61B 5/4869 Determining body composition
• CPC Class Codes: A61B 5/4872 Body fat
• CPC Class Codes: A61B 5/6887 mounted on external non-worn devices, e.g. non-medical devices

Abstract

A body fat measuring apparatus for measuring body fat in a patient'"'"'s body comprises apparatus for simultaneously measuring an impedance between the patient'"'"'s feet, and for measuring the patient'"'"'s height and the patient'"'"'s weight, and a calculator for calculating body fat from the measured impedance value, height and weight. The calculator estimates body density using a formula having a correction term either for increasing the body density upon increase of the impedance compared to the original impedance or a correction term for decreasing the body density upon increase of the weight with respect to the original weight.

Claims

1. A method of measuring impedance of a patient'"'"'s body comprising the steps of:

connecting a plurality of reference resistors each having a known resistance in series with said patient'"'"'s body;

supplying an electric current into a current path through said plurality of reference resistors and said patient'"'"'s body;

measuring voltage drops across any of said reference resistors and/or measuring voltage drops across any groups of adjacent said reference resistors, and measuring a voltage drop due to said patient'"'"'s body by momentarily and successively switching over a voltage drop measuring device for each of said voltage drops;

obtaining a correlation formula between said known resistances of said reference resistors and impedance of said patient'"'"'s body, based on measured values of said voltage drops; and

determining the impedance of said patient'"'"'s body by using the measured value of the voltage drop due to said patient'"'"'s body and said obtained correlation formula.

2. An apparatus for measuring impedance of a patient'"'"'s body comprising a pair of input electrodes and a pair of output electrodes adapted to contact with spaced-apart portions of said patient'"'"'s body;

a plurality of reference resistors each having a known resistance connected in series with input electrodes;

means for supplying an electric current into a current path through said plurality of reference resistors, said input electrodes and said portions of the patient'"'"'s body;

voltage drop measuring means;

switching means for momentarily and successively switching over said voltage drop measuring means across any of said reference resistors and/or across any groups of adjacent said reference resistors, and across said pair of output electrodes to measure voltage drops across the said reference resistors and/or voltage drops across the groups of said reference resistors, and a voltage drop due to said patient'"'"'s body when said current supplying means supplies an electric current into said current path; and

processing means for obtaining a correlation formula between said resistances of said reference resistors and impedance of patient'"'"'s body on the basis of values of said voltage drops measured by said voltage drop measuring means and determining the impedance of said patient'"'"'s body by using the measured value of the voltage drop due to said patient'"'"'s body and said obtained correlation formula.

3. An apparatus for measuring impedance of a patient'"'"'s body comprising:

4. An apparatus for measuring impedance of a patient'"'"'s body comprising:

5. An apparatus for measuring bioelectrical impedance of a patient'"'"'s body comprising an apparatus base of electrical insulating material, a first conductive electrode provided on said base and adapted to contact a skin of said patient'"'"'s body, a second conductive electrode provided on said base and adapted to contact a skin of said patient'"'"'s body, an electric current supplying device for supplying an electric current to said first and second electrodes, a third conductive electrode provided on said base and adapted to contact a skin of said patient'"'"'s body, a fourth conductive electrode provided on said base and adapted to contact a skin of said patient'"'"'s body, and a calculating device for measuring a voltage between said third and fourth electrodes and calculating bioelectrical impedance, whereby a distance through the skin of said patient'"'"'s body between said first or second electrode and said third or fourth electrode is 5 cm or more when all of said first, second, third and fourth electrodes contact the skin of said patient'"'"'s body.

6. An apparatus for measuring bioelectrical impedance of a patient'"'"'s body comprising an apparatus base of electrical insulating material, a first pair of conductive electrodes provided on said base and adapted to contact a skin of said patient'"'"'s body, an electric current supplying device for supplying an electric current to said first pair of electrodes, a second pair of conductive electrodes provided on said base and adapted to contact a skin of said patient'"'"'s body, and a calculating device for measuring a voltage between said second pair of electrodes and calculating bioelectrical impedance, whereby a distance through the skin of said patient'"'"'s body between said first pair of electrodes and said second pair of electrodes is 5 cm or more when all of said first pair of electrodes and said second pair of electrodes contact the skin of said patient'"'"'s body.

7. An apparatus for measuring impedance of a patient'"'"'s body comprising:

8. An apparatus according to claim 7 wherein the first and second pair of conductive electrodes are raised slightly above the insulating base so that they may be sensed by a patient standing on the insulating base.

9. An apparatus for measuring impedance of a patient'"'"'s body comprising: