JPH11347009A - Body fat measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a body fat measuring device which hardly measures inaccurately though it is simply structured, small-sized and lightweight with a simple circuit structure by using a left electrode and a right electrode for applying high frequency signal electric currents and for measuring outputted electric currents. SOLUTION: A pair of electrodes 1 and 2 are used in this device. The electrodes have a mechanism for applying high frequency signals to a part of a subject's body as well as a mechanism for detecting body resistance electric potential generated in the subject's body by the high frequency signals running through the body. Each electrode is brought into contact with the subject's body on a different part of the body, and the body impedance of the subject is measured by an impedance measuring part 4 based on the relation between the applied high frequency signals and the detected body resistance electric potential. Based on the result of the measuring, the subject's body fat is calculated.

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 apparatus for measuring a body fat amount, a body fat percentage, and the like of a subject by measuring a body impedance.

[0002]

2. Description of the Related Art In recent years, obesity above the standard weight has various adverse effects on health management, and thus interest in weight management has been increasing. Further, it has been pointed out that in health management, it is necessary to measure not only mere weight but also body fat, body fat percentage, and the like as an index. Since the body fat percentage can be measured by the specific gravity difference of the constituents of the body, the amount of water eliminated when the whole body including the head is submerged in water is accurately measured, and the total weight and the weight of the excluded water The underwater measurement method, which is determined from, has been adopted for a long time. However, a large-scale device is required to accurately measure the amount of water removed by submerging the whole body in water, and it also imposes a heavy burden on the subject, especially for the elderly and the sick. Not applicable in some cases.

[0003] Therefore, paying attention to the fact that the electrical characteristics differ depending on the type of tissue constituting the human body, a bio-impedance analysis method is used, which estimates body fat percentage by measuring body impedance. Many body fat scales have appeared. These include a built-in impedance measurement function in the weighing scale, in which the foot is brought into contact with two electrodes on each of the left and right sides, or the foot is brought into contact with the electrodes on the weighing scale, There is known a body fat measuring device which measures the impedance between the limbs by gripping the left and right electrodes. The former can be used easily, but the accuracy is often insufficient. On the other hand, it is clear that the latter can perform more accurate measurement, but the function and configuration of the device become full-scale and inevitably become expensive and large.

In addition, two electrodes, a high-frequency signal application electrode (constant current electrode) and a measurement electrode (voltage detection electrode), which are electrically insulated from each other, are respectively arranged on the parts held by the palms of both hands. There has been proposed a quadrupole small body fat percentage measuring device configured to measure the impedance in the body by measuring the change in a high-frequency current circuit formed between both palms by a separate measuring circuit (Japanese Patent Laid-Open No. HEI 9-209572). 5-337
No. 096). In this case, each electrode is required to be in good contact with both hands. For various reasons, partial contact failure is likely to occur, and such a difference in contact resistance tends to cause erroneous measurement.

[0005] In consideration of such circumstances, erroneous measurement due to poor contact between the palm and the electrode is eliminated by connecting the two right and left electrodes constituting the four-pole electrode via a resistor. Attempts have also been made to improve the measurement accuracy (Japanese Patent Application Laid-Open No. 08-154910).

However, according to this prior art, since the left and right electrodes are connected by the resistor and the contact state with each electrode is improved, four electrodes are still used. There are individual differences in the size and state of the palm, and measurement deficiencies due to unstable changes in contact resistance cannot be reliably eliminated. For that purpose, it discloses that a function of avoiding erroneous measurement is added by detecting a state of measurement failure and reporting an alarm.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and uses two electrodes, one on each side, for applying a high-frequency signal current and measuring an output current. It is another object of the present invention to provide a body fat measurement device in which an erroneous measurement hardly occurs while achieving a small size, light weight, and a simplified circuit configuration with a simple configuration.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a function of applying a high-frequency signal to a part of the body of a subject and a body resistance potential generated in the body of the subject by passing the high-frequency signal. Using a pair of electrodes that also has a function of detecting a subject, the pair of electrodes are respectively brought into contact with different parts of the body of the subject, and the subject is measured based on the relationship between the applied high-frequency signal and the detected body resistance potential. Is solved by a body fat measurement device that measures the body impedance of the subject and calculates the body fat based on the measurement result.

In such a body fat measuring apparatus, the high frequency generator 3 can be connected to the first electrode 1 side, and the body impedance measuring section 4 can be connected to the second electrode 2 side. In such a connection, the high-frequency generator 3 and the in-vivo impedance measuring unit 4 are connected in series to the body of the subject, but contact the body of the subject in series with both in parallel. You can do it.

This body fat measuring apparatus is based on the characteristic that the body impedance Z (= r + x) differs depending on the component composition ratio of each element of the human body, and in particular, there is an extreme difference between a fat part and a muscle part and other parts. Therefore, the impedance in the body is determined by the Ohm's law of alternating current, Z = (high-frequency potential) / (high-frequency current), and the body fat is measured based on this. When a high-frequency current of a certain level is applied from the high-frequency generator 3 through, for example, the first electrode 1, a signal flowing through the body and indicating a body resistance potential is detected by, for example, the second electrode 2.

The impedance in the body is measured by performing processing such as amplification and integration on the detected potential signal. Since it is possible to obtain a correspondence table between the body impedance and the characteristics of the subject, for example, gender, height, weight, etc., it is possible to obtain a correspondence table between the body fat mass or the body fat percentage determined as the measurement basic condition, such a correspondence table is used. The body fat mass or the body fat percentage is easily calculated based on the body impedance measured as described above and displayed on the display unit 5.

In the body fat measuring apparatus according to the present invention, the measured value of the body impedance of the subject is
It is obtained by integrating the body resistance potential detected from the body of the subject.

Further, in the body fat measuring apparatus according to the present invention, a calculation table for calculating body fat from the body impedance is stored, and measurement basic conditions such as the sex, height, and weight of the subject are measured. It is calculated from the body impedance value. Also,
At least one of the electrodes is configured as one electrode by electrically short-circuiting a plurality of physically separated electrodes.

[0014]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing a basic configuration of a body fat measurement device according to the present invention. In this embodiment, a high-frequency generation unit 3 and an impedance measurement unit 4 are provided for each of a pair of electrodes 1 and 2.
Are connected, and the impedance measuring unit 4
A display unit 5 for displaying a measurement result is connected.
The common part of the high-frequency generator 3 and the impedance measuring unit 4 is connected to each other.

In such a configuration, various materials can be selected for the materials of the electrodes 1 and 2. However, since the materials are in contact with the human body and take out a weak signal, rust and stains are not generated. Desirable is one that has little adhesion and does not deteriorate over a long period of time. Preferred materials include metal plated plastic, copper or an alloy thereof, aluminum or an aluminum alloy, SUS, carbon, and the like.

As the high-frequency generator 3, well-known high-frequency circuit elements and circuit configurations can be used.
The configuration as shown in FIG. As the high-frequency oscillator 31, an appropriate type of oscillator such as a crystal oscillator, a CPU-based oscillator, or an analog oscillator can be used. The oscillation frequency in this case can be appropriately selected according to the correspondence with the impedance measurement circuit described later.
About 0 kHz to 1000 kHz, preferably 100 kHz
z to about 900 kHz, more preferably 400 kHz to
It can be set to about 750 kHz. The high-frequency signal obtained in this manner has a constant voltage V
The signal is amplified to a required level by an operational amplifier (Op-AMP) 32 supplied with cc. The amplified high-frequency output is applied to a part of the human body of the person to be measured via the electrode 1, for example, to the human body via one of the right and left palms.

As the impedance measuring section 4, well-known high-frequency circuit elements and circuit configurations can be used. For example, a configuration as shown in FIG. 2B can be employed.
Since the human body resistance potential detected by the electrode 2 is weak, it is amplified to a desired level by the amplifier 41 (AMP), and necessary processing including integration processing is performed in the integration circuit including the capacitor 42 and the diode 43. The output processed in this way is displayed on the display unit 5.
In addition, the display unit 5 is capable of literally displaying an analog signal and / or a digital signal, and may be a graphic display or a notification unit in combination with color, sound, sound, or the like.

The above-described high-frequency generation, signal detection, integration processing, calculation of body impedance (Z), calculation of body fat mass or fat percentage, etc. are desirably controlled by a microcomputer, but can be controlled by conventional means. Not detailed.

FIG. 3 shows another embodiment of the present invention. Two electrodes 6, 7 and electrodes 8, 9 are provided for a pair of electrodes 1, 2 in the circuit configuration of FIG. Is connected. The present invention is characterized in that one electrode for high-frequency current application and one electrode for body resistance potential measurement are used, but the electrodes 6 and 7 and the electrodes 8 and 9 shown here are used.
Means that they are electrically short-circuited and integrated, and does not depend on whether they are separated visually or physically.

The connection of each of the electrodes 6, 7 and 8, 9 belongs to the technical scope of the present invention. Such a configuration is advantageous when an appropriate shape can be adopted as an electrode which is separated so as to have a better contact state when it is brought into contact with a palm, a foot or the like. For example, this corresponds to a case where the hand is gripped so as to be sandwiched between the index finger and the thumb. In addition, as a modified example of such an embodiment, one may be a physically single electrode, and only the other may be a combination of a plurality of electrodes electrically short-circuited and integrated. No problem.

FIG. 4 shows still another embodiment of the present invention. In this embodiment, the high-frequency generator 3
And the impedance measuring unit 4 are connected in parallel to one electrode 1
It is connected to the. The other electrode 2 is connected to a measurement reference load (Z) 11 whose impedance value can be specified.

In the above configuration, when measuring body fat, for example, both electrodes 1, 2 or 6-7, 8-9 are grasped and securely brought into contact with the left and right palms. In this state, the high-frequency current generated by the high-frequency generator 3 is applied to the human body of the subject. In this case, the output changed by the human body of the person to be measured is detected by the impedance measuring unit 4, and the detection result is subjected to integration or other processing to specify the impedance in the body. This impedance value is
It is displayed on the display unit 5 as it is, or it refers to the impedance-body fat conversion table stored in advance, and considers the measurement basic conditions such as the sex, height, and weight of the subject to be measured in advance. Fat mass or fat percentage can be obtained.

Although power switches such as the high-frequency generator 3 and the impedance measuring unit 4 in this case are not shown, they can be configured to be turned on in advance before the measurement, and, for example, the subject can turn on the electrodes. It can be configured to be automatically inserted when gripped or contacted measurably, and to automatically shut off when left for a predetermined time.

In each of the above-described embodiments, the display unit 5
In addition to being able to display analog or digital numerical values, various functions such as notifying by voice message, incorporating a small printer, printing out the measurement result, etc. are added, and more reliable output notification It is also possible to configure to perform the following.

[0025]

According to the body fat measuring device of the present invention, a part of the body of the subject, for example, the palm, the flats of the feet, the abdomen,
Only one pair of electrodes to be brought into contact with the back, the shoulder, and the like is required, and a portion including a circuit configuration and an electrode portion structure can be miniaturized. Since the circuit configuration can be simplified, the causes of failures and defects are also reduced, and the manufacturing cost of the device can inevitably be reduced.

Since the contact with the human body is performed only by a pair of electrodes, the chance of poor contact is reduced as compared with the four-electrode type, and the situation becomes inaccurate even when used by an inexperienced subject. Can be avoided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of a body fat measurement device according to the present invention.

FIG. 2 is a block diagram showing a circuit configuration example of a main part of the body fat measurement device according to the present invention.

FIG. 3 is a block diagram showing a configuration of another embodiment of the body fat measurement device according to the present invention.

FIG. 4 is a block diagram showing a configuration of still another embodiment of the body fat measurement device according to the present invention.

[Explanation of symbols]

 1, 2 electrode 3 High frequency generator 4 Impedance measuring unit 5 Display unit 6, 7, 8, 9 electrode 11 Measurement reference load (Z)

Claims (4)

[Claims] 1. A pair of electrodes having both a function of applying a high-frequency signal to a part of a body of a subject and a function of detecting a body resistance potential generated in the body of the subject by passing the high-frequency signal. Using the pair of electrodes, each of the electrodes is brought into contact with a different part of the body of the subject, and the body impedance of the subject is measured from the relationship between the applied high-frequency signal and the detected body resistance potential. A body fat measurement device, wherein the body fat is calculated based on: 2. The body according to claim 1, wherein the measurement value of the body impedance of the subject is obtained by integrating a body resistance potential detected from the body of the subject. Fat measuring device. 3. A calculation table for calculating body fat from the body impedance is stored, and the calculation table is calculated based on measurement basic conditions such as sex, height, and weight of the subject and the body impedance value. The body fat measuring device according to any one of claims 1 and 2, wherein 4. The apparatus according to claim 1, wherein at least one of said electrodes is formed as one electrode by electrically short-circuiting a plurality of physically separated electrodes.
The body fat measuring device according to any one of the above.