JPH105188A - Body fat measurement device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the measurement accuracy of body fat percentage. The disclosed body fat measurement device (4) includes a signal output circuit (5) for applying a multi-frequency current (Ib) to a body (E) of a subject, a current detection circuit (6) for detecting a multi-frequency current (Ib) flowing through the body (E) of the subject. , A voltage detection circuit 7 for detecting a voltage Vp between the limbs of the subject, and a CPU for performing various arithmetic processing
10 and ROM for storing a processing program of CPU 10
11, a RAM 12 for temporarily storing various data, and four surface electrodes Hp, Hc, L to be attached to the limbs of the subject.
p, Lc. The CPU 10 measures the bioelectric impedance based on the detected current Ib and the voltage Vp, and calculates the intracellular fluid resistance of the body of the subject based on the measured bioelectric impedance. Then, based on the intracellular fluid resistance, the body fat state (body fat percentage, fat weight, lean body mass, etc.) of the subject is estimated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a body fat measuring device for electrically measuring the state of body fat (body fat percentage, fat weight, lean body mass, etc.).

[0002]

2. Description of the Related Art It is said that obesity is determined not by appearance and weight but actually by the ratio of fat to body weight, that is, the percentage of body fat. Therefore, in thinking about health promotion, fat control (elimination / prevention of obesity) is more important than weight control, so correct measurement of body fat is of great significance. By the way, it is assumed that the total conduction amount of the body is substantially equal to the total conduction amount of the body water amount, most of which is considered to be contained in muscle tissue, and that the water content of adipose tissue is minimum. From what you can do,
Bioelectric Impedance
Are considered to sufficiently reflect body composition such as body fat. For example, lean body mass (FFM) is proportional to the square of height divided by bioelectrical impedance,
Reported by Lukaski et al. (HCLukaski et
al, The American Journal of Clinical Nutrition, 4
1 (1985) 810-817).

Utilizing the above-described characteristics of bioelectrical impedance, conventionally, for example, Japanese Patent Application Laid-Open No. 5-337097
As described in Japanese Unexamined Patent Publication (Kokai) No. H10-209, four surface electrodes are attached to predetermined portions of the subject's skin surface, that is, to the subject's back part and to the instep part on the same side, two by two. Among them, a sinusoidal alternating current is passed between the two electrodes between the back part and the foot part, the voltage between the limbs of the subject is detected from the remaining two electrodes, and the bioelectric impedance is measured.
2. Description of the Related Art A body fat measurement device for estimating a state of body fat such as a body fat percentage has been developed by making full use of a predetermined body composition estimation formula programmed in advance based on a measured bioelectric impedance.

Here, referring to the cells constituting the tissue of the human body, as shown in FIG.
It is surrounded by cell membranes 2, 2, ...
The cell membranes 2, 2, ... are electrically capacitive (reactance)
Can be seen as a large capacitor. Therefore,
As shown in FIG. 8, the bioelectrical impedance is a parallel composite impedance of an extracellular fluid impedance consisting only of extracellular fluid resistance Re and an intracellular fluid impedance consisting of a series connection of intracellular fluid resistance Ri and cell membrane capacitance Cm. Can be considered. Therefore, in the above-mentioned conventional body fat measurement device, the frequency of the sinusoidal alternating current to be passed between the surface electrodes of the limbs is fixed at 50 kHz, which is the characteristic frequency of the skeletal muscle tissue, and the bioelectric impedance of the subject is measured. The parallel combined impedance of the external fluid impedance and the intracellular fluid impedance was obtained, and the body fat percentage and the like of the subject were calculated based on the obtained parallel combined impedance.
By the way, the body fat percentage is a pure ratio of intracellular fat to muscle, excluding extracellular fluid such as blood (accurately, plasma) and lymph.

[0005]

However, in the above-mentioned conventional body fat measuring device, the body fat percentage and the like are determined based on the bioelectric impedance including the extracellular fluid resistance as described above. For example, immediately after the removal of water during dialysis or immediately after hard training, there is a disadvantage that the measurement error such as the body fat percentage increases due to the influence of the increase in the extracellular fluid resistance. In addition, since the measured body electrical impedance includes the capacitance (reactance) component of the cell membranes 2, 2,..., It has been impeded from improving the accuracy of the estimated values such as the body fat percentage.

[0006] The present invention has been made in view of the above circumstances, and has as its object to provide a body fat measurement device capable of improving the measurement accuracy of the body fat percentage.

[0007]

In order to solve the above-mentioned problems, a body fat measuring device according to the present invention generates a multi-frequency probe current and outputs the generated probe current of each frequency to a subject. A bioelectrical impedance measuring means for measuring the electrical impedance of the subject's body by being inserted into a body; and cells of the subject's body based on the electrical impedance of the subject's body measured by the bioelectrical impedance measuring means. A resistance calculating means for calculating an internal fluid resistance, and a body fat estimating means for estimating a state of body fat of the subject based on the intracellular fluid resistance calculated by the resistance calculating means. And

According to a second aspect of the present invention, there is provided the body fat measuring device according to the first aspect, wherein the bioelectrical impedance measuring means is provided for each frequency of the probe current applied to the body of the subject. The bioelectrical impedance or bioelectrical admittance of the body of the subject is measured, and based on the measured bioelectrical impedance or bioelectrical admittance for each of the measured frequencies, an impedance locus or An admittance trajectory is obtained, and from the obtained impedance trajectory or admittance trajectory, a bioelectric impedance or a bioelectric admittance of the subject at a frequency of 0 and at infinity is calculated. Of the subject calculated by the electrical impedance measuring means. Based on the bioelectrical impedance or bioelectrical admittance at frequencies 0 o'clock and frequency infinite, it is characterized by calculating the intracellular fluid resistance of the subject's body.

Further, the invention according to claim 3 is the body fat measuring device according to claim 1 or 2, wherein at least one of the height, weight, sex and age of the subject is input as human body characteristic data. And the human body characteristic data input means for performing the body fat estimation means,
Estimating the state of the body fat of the subject based on the intracellular fluid resistance of the subject's body calculated by the resistance calculating means and the human body characteristic data input from the body characteristic data inputting means. Features.

[0010]

In the configuration of the present invention, the bioelectrical impedance measuring means generates a multi-frequency probe current and inputs the generated probe current of each frequency into the body of the subject to measure the electrical impedance of the body of the subject. The resistance calculating means obtains the intracellular fluid resistance of the living tissue of the subject based on the electrical impedance of the subject's body measured by the bioelectric impedance measuring means. The body fat estimating means estimates the state of body fat such as the body fat percentage of the subject based on the obtained intracellular fluid resistance. Therefore, according to the configuration of the present invention, the intracellular fluid resistance is accurately obtained, and based on the obtained intracellular fluid resistance, it is possible to obtain a more accurate and accurate estimation value of the body fat according to the actual situation.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. The description will be specifically made using an embodiment. FIG. 1 is a block diagram showing an electrical configuration of a body fat measurement device according to one embodiment of the present invention.
FIG. 3 is a schematic diagram schematically illustrating a use state of the device, FIG. 3 is a diagram illustrating an impedance locus of a human body, FIG. 4 is an electrical equivalent circuit diagram of cells in the tissue, and FIG. FIG. 6 is a diagram showing a display example of a display device in the device. As shown in FIGS. 1 and 2, the body fat measurement device 4 of this example includes a signal output circuit 5 for passing a multi-frequency current Ib as a measurement signal to the body E of the subject, and a multi-frequency circuit flowing through the body E of the subject. Current I
b, a voltage detection circuit 7 for detecting the voltage Vp between the limbs of the subject, a keyboard 8 as an input device, and a display 9 as an output device
A CPU (Central Processing Unit) 10 for performing various controls and various arithmetic processes, and an R for storing a processing program of the CPU 10.
An OM 11, a RAM 12 in which a data area for temporarily storing various data and a work area of the CPU 10 are set, and four surface electrodes Hp, Hc to be attached to the skin surface of the back H or the foot L of the subject at the time of measurement. , Lp and Lc.

The signal output circuit 5 includes a PIO (parallel interface) 51, a measurement signal generator 52, and an output buffer 53. Measurement signal generator 52
Is, for example, at a cycle of 800 nsec during the entire measurement time,
In accordance with an instruction from the CPU 10 performed via the PIO 51, a measurement signal (current) Ia whose frequency changes stepwise in the range of, for example, 1 kHz to 400 kHz and at a frequency interval of 15 kHz is repeatedly generated, and the output buffer 5
Enter 3 The output buffer 53 keeps the input measurement signal Ia in a constant current state while maintaining the multi-frequency current Ia.
It is sent to the surface electrode Hc as b. This surface electrode Hc
Is affixed to the back H of the subject during measurement, so that a multi-frequency current Ib in the range of 500 to 800 μA flows through the body E of the subject.

The current detecting circuit 6 includes an I / V converter (current / voltage converter) 61 and a BPF (bandpass filter).
62, an A / D converter 63 and a sampling memory 64. The I / V converter 61 is a multi-piece that flows between the body electrode Ec of the subject, ie, the surface electrode Hc attached to the back H of the subject (FIG. 2) and the surface electrode Lc attached to the instep L. The frequency current Ib is detected and converted to a voltage Vb, and the voltage Vb obtained by the conversion is converted to a BPF
62. The BPF 62 supplies the A / D converter 63 only through a voltage signal in a band of approximately 1 kHz to 800 kHz in the input voltage Vb. The A / D converter 63 converts the analog input voltage Vb into a digital voltage signal Vb according to a digital conversion instruction issued by the CPU 10.
After that, the digitized voltage signal Vb is stored as current data Vb in the sampling memory 64 for each sampling cycle and for each frequency of the measurement signal Ia. Also,
The sampling memory 64 is composed of an SRAM, and sends a digital voltage signal Vb temporarily stored for each frequency of the measurement signal Ia to the CPU 10 in response to a request from the CPU 10.

The voltage detection circuit 7 includes a differential amplifier 71, a BP
An F (band pass filter) 72, an A / D converter 73, and a sampling memory 74 are provided. The differential amplifier 71 detects the voltage (potential difference) between the surface electrode Hp attached to the body E of the subject, that is, the surface electrode Hp attached to the back H of the subject and the surface electrode Lp attached to the instep L. B
The PF 72 has a frequency of about 1 kHz to
The signal is supplied to the A / D converter 73 only through the 800 kHz band voltage signal. The A / D converter 73 is a CPU 10
Converts the analog input voltage Vp into a digital voltage signal Vp in accordance with the digital conversion instruction issued by the digital signal processor, and converts the digitized voltage signal Vp as voltage data Vp into a sampling memory for each sampling cycle and for each frequency of the measurement signal Ia. 74. The sampling memory 74 is composed of an SRAM, and stores a digital voltage signal Vp temporarily stored for each frequency of the measurement signal Ia in the CPU.
10 is sent to the CPU 10 in response to the request. Note that C
The PU 10 issues a digital conversion instruction to the two A / D converters 63 and 73 at the same timing.

The keyboard 8 is provided with numeric keys and function keys for inputting the human body characteristic items such as the height, weight, sex and age of the subject, the total measurement time and the number of measurements, and the operator (or the subject) starts measurement. Is provided. Operation data and human body characteristic data supplied from the keyboard 8 are converted into key codes by a key code generation circuit (not shown), and
Supplied to The CPU 10 temporarily stores, in the data area of the RAM 12, the various operation signals and the human body characteristic data input with the codes.

The ROM 11 includes, as processing programs for the CPU 10, a main program, a bioelectric impedance calculation subprogram, an impedance locus calculation subprogram, a frequency 0 impedance determination subprogram, a frequency infinity impedance determination subprogram, and a cell program. It stores an internal fluid resistance calculation subprogram, a body fat estimation subprogram, and the like. Here, the bioelectric impedance calculation subprogram describes a procedure for sequentially reading out current data and voltage data for each frequency stored in the sampling memories 64 and 74 and calculating the bioelectric impedance of the subject for each frequency. ing. As described in the “Prior Art” section, the cell membrane 2,
Can be regarded as large-capacity capacitors, the externally applied current flows only through the extracellular fluid 3 when the frequency is low, as shown by solid lines A, A,. . However, as the frequency increases, the current flowing through the cell membranes 2, 2,... Increases, and when the frequency becomes very high, as shown by broken lines B, B,. To flow through.

The impedance trajectory calculation subprogram includes, based on the bioelectric impedance of the subject at each frequency obtained by the operation of the bioelectric impedance calculation subprogram, from the frequency 0 to the frequency infinity according to the least squares calculation method. The processing procedure for calculating the impedance locus up to this point is written. In the “Prior Art” section, cells in human body tissue are represented by simple electrical equivalent circuits (FIG. 8), but in actual human body tissue, cells of various sizes are irregularly arranged. Therefore, the impedance locus of the actual human body is an arc whose center is higher than the real axis as shown by a solid line D in FIG. 3, and the electrical equivalent circuit has a time constant τ = Cmk · Rik as shown in FIG. Is represented by a distributed constant circuit in which is distributed. In the figure, Re represents extracellular fluid resistance, Rik represents intracellular fluid resistance of each cell, and Cmk represents cell membrane capacity of each cell.

The frequency 0-time impedance determination subprogram and the frequency infinity-time impedance determination subprogram are respectively based on the impedance trajectory obtained by the operation of the impedance trajectory calculation subprogram. The method of determining the bioelectrical impedance of the subject is written step by step. In the intracellular fluid resistance calculation subprogram, the intracellular fluid resistance is calculated based on both impedances obtained by operation of the frequency 0-time impedance determination subprogram and the frequency infinity-time impedance determination subprogram. At frequency 0, the measured bioelectric impedance is equivalent to the extracellular fluid resistance, and at infinite frequency, as shown in FIG. 3, the cell membrane loses its capacitive capacity, and the measured bioelectric impedance is It becomes equivalent to the combined resistance of the intracellular fluid resistance and the extracellular fluid resistance (FIG. 5). Therefore, the intracellular fluid resistance is accurately calculated from the bioelectric impedance at the time of the frequency 0 and at the time of the infinity.

The body fat estimation subprogram includes an intracellular fluid resistance obtained by running the intracellular fluid resistance calculation subprogram and the height, weight, gender, age, etc. of the subject input via the keyboard 8. Based on the human body characteristic items, the state of the subject's body fat (body fat percentage, fat weight, lean body mass, etc.) is estimated.

The data area of the RAM 12 further includes a bioelectric impedance storage area for storing a subject's bioelectric impedance obtained by the bioelectric impedance calculation subprogram and the like for each frequency, and an intracellular fluid resistance calculation subprogram. A resistance value storage area for storing the obtained intracellular fluid resistance, a human body characteristic item storage area for storing human body characteristic items such as height, weight, gender, and age of the subject input via the keyboard 8, and a body fat estimation. A body fat storage area for storing numerical values such as the body fat percentage, fat weight, lean body mass, and the like obtained by the subprogram is set.

The CPU 10 controls various parts of the apparatus,
By sequentially executing the processing programs stored in the OM 11 using the RAM 12, the state of the body fat of the subject (body fat percentage, fat weight, lean body mass, etc.) is estimated. The display 9 is composed of, for example, a liquid crystal display panel, and receives input data from the keyboard 8 and calculation results of the CPU 10, such as impedance locus, intracellular fluid resistance, subject's name, height, weight, gender, age, and the like. Displays human body characteristic items.

Next, the operation of this example will be described. First, prior to the measurement, as shown in FIG. 2, two surface electrodes Hc and Hp were placed on the back H of the subject and two surface electrodes Lc
p and Lc are respectively adhered to the instep L on the same side of the subject via conductive cream (at this time, the surface electrodes Hc,
Lc is attached to a portion farther from the center of the human body than the surface electrodes Hp and Lp). Next, the operator (or the subject himself)
Operates the keyboard 8 of the body fat measurement device 4 to input the human body characteristic items such as the height, weight, sex, and age of the subject, and sets the total measurement time, the number of measurements, and the like. The entire measurement period is set so as to be at least 2 seconds or more (the respiratory cycle or more) in order to increase the measurement accuracy. The number of measurements is set to, for example, 100 times.

Next, when the operator (or the subject) turns on the start switch of the keyboard 8, the CPU 10
The signal generation instruction signal SG is issued to the measurement signal generator 52 of the signal output circuit 5. The measurement signal generator 52 includes a CPU 1
When the signal generation instruction signal SG is received from 0, driving is started, and the frequency changes stepwise at a frequency of 1 kHz to 400 kHz and a frequency interval of 15 kHz during the entire measurement time, for example, at a cycle of 800 nsec. Measurement signal I
a is repeatedly generated and input to the output buffer 53.
The output buffer 53 sends out the input measurement signal Ia to the surface electrode Hc as a multi-frequency current Ib while maintaining the input measurement signal Ia in a constant current state (a constant value in a range of 500 to 800 μA). Thereby, the multifrequency current Ib of the constant current flows through the body E of the subject from the surface electrode Hc, and the measurement is started.

When the multi-frequency current Ib is supplied to the body E of the subject, the I / V converter 61 of the current detection circuit 6 generates the multi-frequency current Ib flowing between the limbs to which the surface electrodes Hc and Lc are attached. After being detected and converted into an analog voltage signal Vb, it is supplied to the BPF 62. BP
In F62, 1 kHz is selected from the input voltage signal Vb.
Only the voltage signal component in the band of up to 800 kHz is allowed to pass and supplied to the A / D converter 63. A / D converter 6
In 3, the supplied analog voltage signal Vb is converted into a digital voltage signal Vb, and as current data Vb,
It is stored in the sampling memory 64 for each predetermined sampling period and for each frequency of the measurement signal Ia. In the sampling memory 64, the stored digital voltage signal Vb is
The data is sent to the CPU 10 in response to the request from the PU 10. On the other hand, in the differential amplifier 71 of the voltage detection circuit 7, the voltage Vp generated between the limbs to which the surface electrodes Hp and Lp are attached
Is detected and supplied to the BPF 72. In the BPF 72, 1 kHz to 800 out of the input voltage signal Vp.
Only the voltage signal component in the kHz band is allowed to pass, and A
/ D converter 73. In the A / D converter 73,
The supplied analog voltage signal Vp is converted into a digital voltage signal Vp, and is stored as voltage data Vp in the sampling memory 74 for each predetermined sampling period and for each frequency of the measurement signal Ia. Sampling memory 74
Then, the stored digital voltage signal Vp is
Is sent to the CPU 10 in response to the request. CPU10
Controls each part of the apparatus and repeats the above-described processing for a designated number of measurements (in this case, 100 times).

When the number of measurements reaches 100, C
After performing the control to stop the measurement, the PU 10 first activates the bioelectrical impedance calculation subprogram, and sequentially reads the current data and the voltage data for each frequency stored in the sampling memories 64 and 74. Then, the bioelectrical impedance (average value of 100 times of measurement) of the subject for each frequency is calculated. In addition,
The calculation of the bioelectric impedance includes the calculation of its components (resistance and reactance). Next, the CPU 10
Starts the impedance locus calculation subprogram, and performs curve fitting using the least squares method based on the subject's bioelectric impedance and its components (resistance and reactance) for each frequency obtained by the bioelectric impedance calculation subprogram. The impedance locus from the frequency 0 to the frequency infinity is calculated according to the method described in (1). The impedance locus calculated in this manner is an arc whose center is higher than the real axis, as shown in FIGS. 6 (a) and 6 (b).

Next, according to the impedance trajectory obtained by the impedance trajectory calculation subprogram, the CPU 10 executes the operation according to the impedance trajectory obtained at the time of the frequency 0 and the infinity at the frequency 0 according to the impedance determination subprogram at the frequency 0 and the infinity at the infinity frequency. The bioelectric impedance of the subject at the time is obtained. In other words, the points at which the arcs of the impedance locus intersect the X axis in the figure are the bioelectric impedances at the frequency of 0 Hz and infinity, respectively. Next, the CPU 10 calculates the intracellular fluid resistance based on the two impedances obtained by the impedance determination subprogram at the frequency of 0 and the impedance determination subprogram at the infinite frequency at the frequency according to the intracellular fluid resistance calculation subprogram. Next, according to the processing procedure of the body fat estimation subprogram, the CPU 10 determines the intracellular fluid resistance obtained by running the intracellular fluid resistance ratio calculation subprogram, and the height and weight of the subject input via the keyboard 8. The body fat state (body fat percentage, fat weight, lean body mass, etc.) of the subject is estimated based on the human body characteristic items such as gender and age.

Finally, the CPU 10 stores the calculated body fat status (body fat percentage, fat weight, lean body mass, etc.) of the subject in the RAM 12 and, as shown in FIG. Resistance, subject's name, height,
The human body characteristic items such as weight, sex and age are displayed on the display 9. Then, the series of processing ends.

As described above, according to the above configuration, the extracellular fluid resistance and the volume component of the cell membrane are removed, and only the intracellular fluid resistance is determined. Based on the determined intracellular fluid resistance, the body of the subject is determined. The state of body fat such as fat percentage is estimated. Therefore, it is possible to obtain a more accurate estimated value that is more realistic. The impedance trajectory is calculated by the impedance trajectory calculation subprogram, and the impedance trajectory is determined using the least squares calculation method. Since the bioelectric impedance at 0 and infinity is obtained, the influence of stray capacitance and external noise when high frequency is applied can be avoided.
Direct injection of direct current to the human body can be avoided. Therefore, measurement accuracy is improved.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and there are design changes and the like that do not depart from the gist of the present invention. Is also included in the present invention. For example, the frequency range of the measurement signal (current) Ia is 1 kHz to 400 kHz.
It is not limited to. Similarly, the number of frequencies is arbitrary as long as it is plural. Also, instead of calculating the bioelectrical impedance, a bioelectrical admittance may be calculated, and accordingly, an admittance locus may be calculated instead of calculating an impedance locus. Further, in the above-described embodiment, the bioelectric impedance at the time of the frequency 0 and at the time of infinity was obtained by using the method of curve fitting by the least square method,
However, the present invention is not limited to this. If the influence of stray capacitance or external noise can be avoided by other means, for example, two frequencies (5 kHz)
z, a low-frequency and a high-frequency of 200 kHz or more) are generated and input to the subject, and the bioelectric impedance of the subject's body at low frequency is regarded as the bioelectric impedance at frequency 0, and the subject's body is measured. The bioelectric impedance at high frequency may be regarded as the bioelectric impedance at infinite frequency. Further, in the above-described embodiment, the height of the subject,
Although the case of inputting the weight, sex, age, and the like has been described, a part thereof may be omitted or a race item may be added as necessary. Further, a printer may be provided as an output device. In the above-described embodiment, of the four surface electrodes Hc, Hp, Lc, and Lp, two surface electrodes Hc and Hp are provided on the back part H of the subject E, and the remaining two surface electrodes Lc and Lp are provided. Although the present invention is applied to the instep L of the subject E, the present invention is not limited to this. For example, all four may be attached to the foot.

[0030]

As described above, according to the body fat measuring apparatus of the present invention, the extracellular fluid resistance and the volume component of the cell membrane are removed, and the intracellular fluid resistance is accurately determined. Based on the internal fluid resistance, the state of the body fat such as the body fat percentage of the subject is estimated. Therefore, it is possible to obtain a more accurate estimated value that is more realistic. In addition, using the least-squares calculation method, an impedance locus or an admittance locus is obtained, bioelectrical impedances at a frequency of 0 and infinity are obtained from the obtained locus. Since the internal liquid resistance is calculated, it is possible to avoid the influence of stray capacitance and external noise when high frequency is applied, and to avoid direct application of direct current to the human body. Therefore, measurement accuracy is improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of a body fat measurement device according to one embodiment of the present invention.

FIG. 2 is a schematic diagram schematically showing a use state of the device.

FIG. 3 is a diagram illustrating an impedance locus of a human body.

FIG. 4 is an electrical equivalent circuit diagram of cells in a tissue.

FIG. 5 is an electrical equivalent circuit diagram of cells in a tissue at an infinite frequency.

FIG. 6 is a diagram showing a display example of a display device in the same device.

FIG. 7 is a schematic diagram schematically showing cells in a tissue of a human body.

FIG. 8 is an electrical equivalent circuit diagram of cells in a tissue.

[Explanation of symbols]

4 Body Fat Measurement Device 5 Signal Output Circuit (Part of Bioelectric Impedance Calculation Means) 52 Measurement Signal Generator 53 Output Buffer 6 Voltage Detection Circuit (Part of Bioelectric Impedance Calculation Mean) 61 I / V Converter 62 BPF 63 A / D converter 64 Sampling memory 7 Voltage detection circuit (part of bioelectrical impedance calculating means) 71 Differential amplifier 72 BPF 73 A / D converter 74 Sampling memory 8 Keyboard (human body characteristic data input means) 10 CPU (biological body) Electric impedance calculating means,
Resistance calculation means, body fat estimation means) 11 ROM 12 RAM Hc, Hp, Lc, Lp Surface electrode E Subject's body H Subject's back part L Subject's instep part Ia Measurement signal Ib Multi-frequency current (multi-frequency probe current ) Vp The voltage between the subject's limbs

Claims (3)

[Claims] Generating a multi-frequency probe current;
Bioelectrical impedance measuring means for applying the generated probe current of each frequency to the body of the subject to measure the electrical impedance of the body of the subject; and the electric impedance of the body of the subject measured by the bioelectrical impedance measuring means On the basis of,
A resistance calculating means for calculating the intracellular fluid resistance of the body of the subject, and a body fat estimating means for estimating a state of the body fat of the subject based on the intracellular fluid resistance calculated by the resistance calculating means. A body fat measurement device, comprising: 2. The bioelectrical impedance measuring means measures a bioelectrical impedance or a bioelectrical admittance of the body of the subject for each frequency of the probe current applied to the body of the subject, and measures each measured bioelectrical impedance. Based on the bioelectrical impedance or bioelectrical admittance for each frequency, using the least-squares method, an impedance trajectory or an admittance trajectory is determined. The bioelectrical impedance or the bioelectrical admittance at the time of the frequency 0 and the frequency infinity are calculated, and the resistance calculating unit calculates the bioelectrical impedance at the frequency 0 and the frequency infinity of the body of the subject calculated by the bioelectrical impedance measuring unit. Bioelectrical impedance of a living body Based on the gas admittance, body fat measuring apparatus according to claim 1, wherein the calculating the intracellular fluid resistance of the subject's body. 3. A human body characteristic data inputting means for inputting at least one of height, weight, sex and age of the subject as human body characteristic data, and said body fat estimating means is provided with: Estimating the state of body fat of the subject based on the intracellular fluid resistance of the subject's body calculated by the calculating means and the human body characteristic data input from the body characteristic data inputting means. The body fat measurement device according to claim 1 or 2, wherein the body fat is measured.