JP2011251158A - Subcutaneous fat thickness measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely measure a fat thickness in a portion contacting with a measuring electrode out of the human body, when the measuring electrode contacts with the human body.SOLUTION: The subcutaneous fat thickness Lf in the portion contacting with the measuring electrode out of the human body is found based on a phase difference between a current flowing in a current route from one of electrodes to the other electrode via the human body out of the first current supplying electrode 12a and the second current supplying electrode 12b, and a voltage measured by the first voltage measuring part 30, by perceiving a difference in generation manners of phase differences as to a fat layer and a muscle layer.

Description

  The present invention relates to a subcutaneous fat thickness measuring apparatus for measuring the thickness of subcutaneous fat in a human body.

  2. Description of the Related Art Conventionally, a technique for measuring the subcutaneous fat thickness of a human body based on impedance measured by bringing a measurement electrode into contact with a hand or a foot is known (see, for example, Patent Document 1).

JP 2001-178697 A

However, as in Patent Document 1, the technique of measuring subcutaneous fat thickness based only on impedance cannot capture only fat information, and the measured value varies depending on the state of muscle existing under the fat. Therefore, there is a problem that it is difficult to accurately measure the subcutaneous fat thickness.
In view of the above circumstances, an object of the present invention is to solve the problem of accurately measuring subcutaneous fat thickness.

  In order to solve the above-described problems, the subcutaneous fat thickness measurement apparatus according to the present invention is a first measurement electrode (first measurement electrode 12 shown in FIG. 1) that is used for measurement in contact with the human body. Current application electrode, second current application electrode, first voltage measurement electrode and second voltage measurement electrode, and between the first current application electrode and the second current application electrode. A current generator (a first current generator 28 shown in FIG. 2) that outputs a flowing alternating current; a first voltage measuring electrode disposed adjacent to the first current application electrode; and a second A voltage measuring unit (first voltage measuring unit 30 shown in FIG. 2) that measures a voltage between a second voltage measuring electrode arranged adjacent to the current applying electrode, and the measuring electrode contacts the human body One of the first current applying electrode and the second current applying electrode. A first current application electrode and a second current application electrode based on a phase difference between a current flowing through a current path from the human body to the other electrode and a voltage measured by the voltage measurement unit; And a subcutaneous fat thickness measurement unit (control unit 44 shown in FIG. 2) for obtaining the subcutaneous fat thickness between the two.

  In this aspect, paying attention to the difference in how the phase difference occurs between the fat layer and the muscle layer, when the measurement electrode comes into contact with the human body, the first current application electrode and the second current application electrode The measurement electrode contacts the human body based on the phase difference between the current flowing from one of the electrodes through the human body to the other electrode and the voltage measured by the voltage measurement unit. Subcutaneous fat thickness at the site was determined. More specifically, the subcutaneous fat thickness measurement unit calculates reactance (imaginary part of impedance) calculated from the impedance calculated from the current flowing through the current path and the voltage measured by the voltage measurement unit, and the phase difference. Based on the resistance (the real part of the impedance), the subcutaneous fat thickness is obtained.

  More specifically, the muscle layer has the property of easily causing a phase difference, while the fat layer has the property of hardly causing a phase difference. Therefore, as the subcutaneous fat thickness increases, the property of the fat layer becomes dominant. While the phase difference becomes smaller, the smaller the subcutaneous fat thickness, the more dominant the muscle layer properties and the larger the phase difference. Then, the ratio of reactance to resistance decreases as the subcutaneous fat thickness increases, and the ratio of reactance to resistance increases as the subcutaneous fat thickness decreases. Using this relationship, the subcutaneous fat thickness measurement unit calculates the ratio of reactance and resistance, and determines the subcutaneous fat thickness corresponding to the calculated ratio value. Thereby, there exists an advantage that subcutaneous fat thickness can be measured accurately.

  Also, the subcutaneous fat thickness measurement unit is based on the impedance calculated from the current flowing through the current path and the voltage measured by the voltage measurement unit, and the reactance calculated from the impedance and the phase difference. Thickness can also be determined.

  Further, the subcutaneous fat thickness measurement unit is configured to calculate the subcutaneous fat based on the impedance calculated from the current flowing through the current path and the voltage measured by the voltage measurement unit, and the resistance obtained from the impedance and the phase difference. Thickness can also be determined.

  As a preferred aspect of the subcutaneous fat thickness measuring apparatus according to the present invention, the first current applying electrode and the second current applying electrode are provided between the first voltage measuring electrode and the second voltage measuring electrode. It is arranged so as to be sandwiched between. According to this aspect, the first voltage measurement electrode and the second voltage measurement electrode are sandwiched between the first current application electrode and the second current application electrode. The distance between the current application electrode and the second current application electrode can be reduced. In general, there is a variation in how fat is applied to the human body, and the amount of attached fat varies depending on the region (that is, the subcutaneous fat thickness varies). Therefore, the first current application electrode and the second current application electrode If the distance between is large, measurement errors are likely to occur. According to the aspect of the present invention, since the distance between the first current application electrode and the second current application electrode can be reduced, the subcutaneous fat thickness can be measured pinpointly. Thereby, there exists an advantage that a measurement precision can be improved.

  As a preferred aspect of the subcutaneous fat thickness measuring apparatus according to the present invention, the first current application electrode, the second current application electrode, the first voltage measurement electrode, and the second voltage measurement electrode are: The distance in the first direction between the first current application electrode and the second current application electrode is arranged along the direction, the width in the first direction of the first voltage measurement electrode, Smaller than the sum of the width in the first direction of the voltage measuring electrode. According to this aspect, the first voltage measurement electrode and the second voltage measurement electrode cannot be disposed between the first current application electrode and the second current application electrode, The distance between the first current application electrode and the second current application electrode can be set to a small value.

  As a preferred embodiment of the subcutaneous fat thickness measuring apparatus according to the present invention, an obesity information measuring unit for measuring information relating to obesity of the measurement subject (for example, body weight, body fat percentage fp and body fat mass fa), and fat thickness measuring unit Based on the measured subject's subcutaneous fat thickness and the information on the subject's obesity measured by the obesity information measuring unit, an index relating to the subject's body composition (for example, visceral fat area, And a body composition index measurement unit for obtaining a visceral fat mass, a subcutaneous fat area, and a subcutaneous fat mass).

It is a figure which shows the external appearance of the subcutaneous fat thickness measuring apparatus which concerns on embodiment of this invention. It is a block diagram which shows the detailed structure of the subcutaneous fat thickness measuring apparatus which concerns on the same embodiment. It is a flowchart which shows operation | movement of the subcutaneous fat thickness measuring apparatus which concerns on the same embodiment. It is the schematic of the structure | tissue of a human body. It is a figure which shows the equivalent circuit of the structure | tissue of a human body. It is a schematic diagram which shows a mode when an alternating current flows through a human body. It is a figure which shows the equivalent circuit of a muscle layer and a fat layer. It is a correlation diagram which shows the relationship between the subcutaneous fat thickness estimated with the method of this embodiment, and the fat thickness measured with the ultrasonic wave. It is a correlation diagram which shows the relationship between the internal fat area estimated by the method of this embodiment, and the internal fat area measured by the CT scan method. It is a correlation diagram which shows the relationship between the visceral fat mass estimated by the method of this embodiment, and the visceral fat mass measured by the CT scan method. It is a correlation diagram which shows the relationship between the subcutaneous fat area estimated by the method of this embodiment, and the subcutaneous fat area measured by CT scan method. It is a correlation diagram which shows the relationship between the amount of subcutaneous fat estimated by the method of this embodiment, and the amount of subcutaneous fat measured by the CT scan method. It is a figure which shows the external appearance of the subcutaneous fat thickness measuring apparatus which concerns on the modification of this invention. It is a block diagram which shows the detailed structure of the subcutaneous fat thickness measuring apparatus which concerns on the modification. It is a flowchart which shows operation | movement of the subcutaneous fat thickness measuring apparatus which concerns on the modification. It is a figure which shows the relationship between an impedance, reactance, resistance, and a phase difference. It is a figure which shows the relationship between phase difference and subcutaneous fat thickness. It is a figure which shows the relationship between ratio of two impedances from which frequency differs, and ratio of reactance and resistance. It is a figure which shows the relationship between ratio of two impedances from which frequency differs, and subcutaneous fat thickness.

<A: Configuration>
FIG. 1 is a diagram illustrating an appearance of a subcutaneous fat thickness measuring apparatus 100 according to the present embodiment. The subcutaneous fat thickness measuring apparatus 100 according to the present embodiment has not only a function of measuring the subcutaneous fat thickness of the measurement subject, but also information relating to obesity such as the measured subject's weight, body fat percentage, and body fat mass by a known method. It also has a function to measure. As shown in FIG. 1, the subcutaneous fat thickness measuring apparatus 100 includes a gripping unit 10 and a mounting unit 20. The gripping unit 10 is connected to the mounting unit 20 via a cable 200, and a first measurement electrode 12 (12a, 12b) for measuring the subcutaneous fat thickness by contacting the human body on the surface of the tip unit. , 12c, 12d) are arranged.

  The first measurement electrode 12 includes a first current application electrode 12a, a second current application electrode 12b, a first voltage measurement electrode 12c, and a second voltage measurement electrode 12d. The first current application electrode 12a and the second current application electrode 12b are disposed so as to be sandwiched between the first voltage measurement electrode 12c and the second voltage measurement electrode 12d. The first voltage measuring electrode 12c is disposed adjacent to the first current applying electrode 12a, and the second voltage measuring electrode 12d is adjacent to the second current applying electrode 12b. Be placed. More specifically, the first measurement electrodes 12 (12a, 12b, 12c, 12d) are arranged along the Y direction on the front end surface of the gripping unit 10, and the first voltage measurement electrode 12c is the first voltage measurement electrode 12c. The second voltage measurement electrode 12d is adjacent to the positive side in the Y direction when viewed from the second current application electrode 12b. Are arranged as follows.

  The distance L in the Y direction between the first current application electrode 12a and the second current application electrode 12b is equal to the width W in the Y direction of the first voltage measurement electrode 12c and the second voltage measurement electrode 12c. The value is set to be smaller than the sum of the width W of the electrode 12d in the Y direction. In this embodiment, the dimensions of the measurement electrodes are set to the same value, and the width W in the Y direction of the first voltage measurement electrode 12c and the width W in the Y direction of the second voltage measurement electrode 12d Are the same value (ie L <2W). In the present embodiment, the distances in the Y direction between the measurement electrodes are set to be equal, and the value is equal to the value of the width W in the Y direction of one measurement electrode (that is, L = W). . Here, the value of the width W in the Y direction in one measurement electrode is set to 5 mm.

  The mounting unit 20 includes a display unit 22, an input unit (26a, 26b, 26c, 26d), and a second measurement electrode 23 (23a, 23b, 23c, 23d) on the appearance. The second measurement electrode 23 is an electrode for measuring the body fat percentage of the measurement subject by contacting the measurement subject's foot. The second measurement electrode 23 includes a third current application electrode 23a, a fourth current application electrode 23b, a third voltage measurement electrode 23c, and a fourth voltage measurement electrode 23d. The third current application electrode 23a and the fourth current application electrode 23b are arranged at positions separated from each other in the X direction. More specifically, the third current application electrode 23a is arranged corresponding to the position on which the left foot of the person to be measured is placed, and the fourth current application electrode 23b is in a position on which the right foot of the person to be measured is placed. Correspondingly arranged. The third voltage measuring electrode 23c is arranged adjacent to the positive side in the Y direction when viewed from the third current applying electrode 23a, and is arranged corresponding to the position where the left foot of the measurement subject is placed. Is done. The fourth voltage measurement electrode 23d is arranged so as to be adjacent to the positive side in the Y direction when viewed from the fourth current application electrode 23b, and is arranged corresponding to the position where the right foot of the measurement subject is placed. .

  The input unit (26a, 26b, 26c, 26d) includes a setting key 26a, an up key 26b, a down key 26c, and a start key 26d. Here, the up key 26b and the down key 26c select information and switch numerical values, and the setting key 26a sets the selected information and switched numerical values. The start key 26d is a means for starting power supply to the mounting unit 20 for a series of measurements. The detailed configuration of the mounting unit 20 will be described later.

  FIG. 2 is a block diagram showing a detailed configuration of the subcutaneous fat thickness measuring apparatus 100 according to the present embodiment. As shown in FIG. 2, in addition to the display unit 22, the second measurement electrode 23, and the input unit 26, the mounting unit 20 includes a first current generation unit 28, a first voltage measurement unit 30, and a second current. The generator 32, the second voltage measurement unit 34, the weight measurement unit 36, the power supply unit 38, the memory 42, and the control unit 44 are provided.

  The first current generator 28 is a means for outputting an alternating current flowing between the first current application electrode 12 a and the second current application electrode 12 b in the gripping unit 10. In the present embodiment, the frequency of the alternating current output from the first current generator 28 is set to 50 kHz (the same applies to the alternating current output from the second current generator 32 described later). The first voltage measuring unit 30 is means for measuring a voltage between the first voltage measuring electrode 12c and the second voltage measuring electrode 12d. The second current generator 32 is a means for outputting an alternating current flowing between the third current application electrode 23a and the fourth current application electrode 23b. The second voltage measuring unit 34 is a means for measuring the voltage between the third voltage measuring electrode 23c and the fourth voltage measuring electrode 23d. The weight measuring unit 36 is a means for measuring the weight of the person on the mounting unit 20 and outputting weight data. The power supply unit 38 is means for supplying power to each part of the electrical system of the mounting unit 20. The memory 42 includes various calculation formulas for calculating the body fat percentage, body fat mass, subcutaneous fat thickness, visceral fat area, visceral fat mass, subcutaneous fat area, subcutaneous fat mass and the like of the measurement subject. It is means for storing inputted body specific information (gender, height, age, etc.), result information, and the like. The control unit 44 is means for executing various control processes.

<B: Operation of subcutaneous fat thickness measuring device>
Next, the operation of the subcutaneous fat thickness measuring apparatus 100 will be described. In the present embodiment, the measurement subject holds the grip unit 10 and rides on the second measurement electrode 23 of the mounting unit 20 with bare feet, and then places the grip unit on the part of his body where the subcutaneous fat thickness is to be measured. Press 10 tips. Various measurement results (such as subcutaneous fat thickness) are displayed on the display unit 22. The specific contents will be described below with reference to FIG. FIG. 3 is a flowchart showing a specific operation of the subcutaneous fat thickness measuring apparatus 100 according to the present embodiment.

  First, when the start key 26d is turned on by the person to be measured (step S1), power supply from the power supply unit 38 is started, and the subcutaneous fat thickness measuring apparatus 100 enters the measurement mode. When the setting key 26a is turned on in a state where the start key 26d is not turned on (when the power is off), the setting mode is set, and setting of the body identification information is possible. At this time, a cursor appears at any position of gender, height, and age displayed on the display unit 22, and the measurement subject operates these buttons by operating the up key 26b, the down key 26c, and the setting key 26a. Information and numerical values can be switched and set. The body specifying information set in this way is stored in the memory 42. If the body identification information has not been set in the past, new registration is performed. If the body identification information has been set in the past, update registration is performed.

  Next, when the person to be measured gets on the mounting unit 20, the control unit 44 measures the weight of the person to be measured (step S2).

  More specifically, it is as follows. When the person to be measured gets on the mounting unit 20, the weight measuring unit 36 outputs weight data corresponding to the weight of the person to be measured. The control unit 44 obtains the body weight of the person to be measured from the weight data output from the weight measurement unit 36 and stores the value in the memory 42.

  Subsequently, the control unit 44 measures the body fat percentage and the body fat amount of the measurement subject (step S3). More specifically, it is as follows. Now, the back of the subject's left foot is in contact with the third current application electrode 23a and the third voltage measurement electrode 23c. The back of the right foot is in contact with the fourth current application electrode 23b and the fourth voltage measurement electrode 23d. As a result, a current path is formed from one of the third current application electrode 23a and the fourth current application electrode 23b to the other electrode via the measurement subject. The alternating current output from the second current generator 32 flows through the current path. At this time, the control unit 44 obtains the impedance between the legs of the measurement subject from the value of the current flowing through the current path and the value of the voltage measured by the second voltage measurement unit 34, and stores the result in the memory 42. save.

And the control part 44 calculates | requires a body fat rate by substituting the to-be-measured person's weight, the impedance between both legs, sex, height, and age in the calculation formula of the body fat rate preserve | saved in the memory 42. The calculation formula of the body fat percentage is expressed by the following formula (1).
fp = α × Zle50 + β × weight + γ × height + δ × age + ε × sex + ζ (1)
In the above formula (1), fp is a body fat percentage, Zle50 is an impedance between both legs, and α to ζ are constants.

Further, the control unit 44 substitutes the body fat percentage fp obtained from the above formula (1) and the body weight of the person to be measured into the calculation formula for the body fat amount stored in the memory 42, thereby obtaining the body fat mass. Ask for. The calculation formula for the body fat mass is expressed by the following formula (2).
fa = fp × weight (2)
In the above formula (2), fa is the body fat mass.
As described above, the control unit 44 obtains the body weight of the person to be measured based on the weight data output from the weight measurement unit 36. Further, the control unit 44 calculates the body fat based on the body weight thus obtained and the impedance measured using the second measurement electrode 23, the second current generation unit 32, and the second voltage measurement unit 34. Find rate fp and body fat mass fa. In other words, the control unit 44, the weight measurement unit 36, the second measurement electrode 23, the second current generation unit 32, and the second voltage measurement unit 34 provide information related to the subject's obesity (for example, body weight, body fat percentage fp, and body fat. It functions as an obesity information measuring unit that measures the amount fa).

  Next, when the measurement subject presses the distal end portion of the grasping unit 10 against a portion of his / her body where the subcutaneous fat thickness is to be measured, the control unit 44 causes the first measurement electrode in the measurement subject's body. Subcutaneous fat thickness is measured at the site where 12 (12a, 12b, 12c, 12d) contacts (step S4). More specifically, when the first measurement electrode 12 (12a, 12b, 12c, 12d) comes into contact with the measurement subject, one of the first current application electrode 12a and the second current application electrode 12b is selected. A current path is formed from one electrode to the other electrode via the measurement subject. The alternating current output from the first current generator 28 flows through the current path. Based on the phase difference between the current flowing through the current path and the voltage measured by the first voltage measurement unit 30, the control unit 44 uses the first current application electrode 12a and the second current application electrode 12b. Subcutaneous fat thickness between is determined.

  Here, the difference between the phase difference that occurs when the alternating current output from the first current generator 28 flows through the muscle layer of the measurement subject and the phase difference that occurs when it flows through the fat layer will be described in detail. As shown in FIG. 4, a human tissue (muscle tissue and adipose tissue) has a plurality of cell membranes 52 each containing an intracellular fluid 50 and an extracellular fluid 54 interposed between the cell membranes 52. When the capacitive component of the cell membrane 52 is Cm, the resistance component of the intracellular fluid 50 is Ri, and the resistance component of the extracellular fluid 54 is Re, the muscle tissue and the adipose tissue can be represented by the equivalent circuit shown in FIG.

  In the adipose tissue, since the intracellular fluid 50 is hardly contained in the cell membrane 52, the value of the resistance Ri of the intracellular fluid 50 is much larger than the value of the resistance Re of the extracellular fluid 54. (Re << Ri). For this reason, when the alternating current output from the first current generation unit 28 flows through the adipose tissue, most of the current flows through the resistance component Re of the extracellular fluid. Therefore, the current and the first voltage measurement unit 30 There is almost no phase difference from the measured voltage. On the other hand, in the muscle tissue, since the intracellular fluid 50 is contained in the cell membrane 52, when the alternating current output from the first current generator 28 flows through the muscle tissue, the current is a resistance component of the extracellular fluid. Not only Re but also the capacitive component Cm of the cell membrane 52 and the resistance component Ri of the intracellular fluid 50 flow. Therefore, there is a phase difference between the alternating current output from the first current generator 28 and the voltage measured by the first voltage measurement unit 30.

  That is, the muscle layer has the property of easily causing a phase difference, while the fat layer has the property of hardly causing a phase difference. Therefore, as the subcutaneous fat thickness increases, the property of the fat layer becomes dominant and the phase difference is increased. On the other hand, the smaller the subcutaneous fat thickness, the more dominant the properties of the muscle layer and the greater the phase difference. In the present embodiment, this is used to measure the subcutaneous fat thickness.

  More specifically, it is as follows. The control unit 44 measures the current output from the first current generation unit 28 and the first voltage measurement unit 30 when the first measurement electrode 12 (12a, 12b, 12c, 12d) contacts the human body. In addition to obtaining the phase difference between the two, the impedance is calculated. Further, the control unit 44 obtains a resistance R that is a real part of the impedance and a reactance X that is an imaginary part of the impedance from the phase difference and the impedance, and then is a ratio R of the reactance X and the resistance R. Find / X. The smaller the phase difference, the smaller the ratio of reactance X to resistance R, while the larger the phase difference, the larger the ratio of reactance X to resistance R. And the control part 44 determines the subcutaneous fat thickness corresponding to the calculated | required value of R / X.

Here, the relationship between the above R / X and subcutaneous fat thickness will be described. FIG. 6 schematically shows a state in which the alternating current output from the first current generator 28 flows through the fat layer and muscle layer of the measurement subject when the first measurement electrode 12 contacts the measurement subject. FIG. The hatched portion shown in FIG. 6 indicates the current path of the alternating current. Further, Lf shown in FIG. 6 is the thickness of the fat layer (subcutaneous fat thickness). FIG. 7 is a diagram showing an equivalent circuit of the fat layer and the muscle layer at this time. Rf shown in FIG. 7 is a resistance component of the fat layer. As described above, in the fat layer, the capacity component can be almost ignored. Zm represents a portion corresponding to the muscle layer, Rj represents a resistance component of the extracellular fluid 54 in the muscle layer, Rk represents a resistance component of the intracellular fluid 50 in the muscle layer, and Cl represents a cell membrane 52 in the muscle layer. The capacity component of is shown. At this time, R / X, which is the ratio of reactance X and resistance R at the part of the body of the person to be measured that is in contact with the measurement electrode, is expressed by the following equation (3).
R / X = -ωClRk-{(ωClRk) ² +1} / (ωClRj)-{(ωClRk) ² +1} / (ωClRf) (3)
Further, since the resistance component Rf of the fat layer is inversely proportional to the subcutaneous fat thickness Lf, the relationship between them is expressed by the following equation (4).
Rf = k / Lf (4)
In the above formula (4), k is a constant.

From the above formulas (3) and (4), the subcutaneous fat thickness Lf is expressed by the following formula (5).
Lf = −ωClk / {(ωClRk) ² +1} × [(ωClRk) + {(ωClRk) ² +1} / (ωClRj) + R / X]
= -Ab × R / X (5)
In the above formula (5), a and b are constants. As understood from the above formula (5), the subcutaneous fat thickness Lf and R / X are in a proportional relationship. That is, the larger the subcutaneous fat thickness Lf, the more dominant the fat layer properties and the smaller the phase difference, so the ratio of reactance X to resistance R decreases (the value of R / X increases), and subcutaneous fat thickness It can be seen that the smaller the Lf, the more dominant the muscle layer properties and the greater the phase difference, so the ratio of reactance X to resistance R increases (R / X decreases).

  In the present embodiment, the above equation (5) is stored in the memory 42 in advance. And the control part 44 substitutes the value of R / X calculated | required previously to the calculation formula (above-mentioned Formula (5)) of the subcutaneous fat thickness preserve | saved in the memory 42, and is the subcutaneous fat thickness Lf. Determine the value.

  FIG. 8 is a correlation diagram showing the relationship between the calculated value of subcutaneous fat thickness using the above equation (5) and the measured value of subcutaneous fat thickness measured by ultrasound. As shown in FIG. 8, a high correlation with a correlation coefficient r = 0.993 is obtained between the calculated value of the subcutaneous fat thickness using the above equation (5) and the measured value of the subcutaneous fat thickness measured by the ultrasonic wave. The standard error estimation (SEE) is 1.44 mm, and the calculated value using the above equation (5) is within the error 1.44 mm. It can be seen that the correlation is high. Therefore, according to the estimation method using the above equation (5), it is possible to estimate with high accuracy by using the value of R / X as a parameter.

  Next, the control unit 44 calculates an index related to the body composition of the measurement subject (step S5 in FIG. 3). In the present embodiment, the “index for body composition” corresponds to the visceral fat area, the visceral fat mass, the subcutaneous fat area, and the subcutaneous fat mass. The specific contents will be described below.

The control unit 44 obtains the visceral fat area by substituting each of the subcutaneous fat thickness Lf and the body fat mass fa of the measurement subject previously obtained for the calculation formula of the visceral fat area stored in the memory 42. . The calculation formula of the visceral fat area is expressed by the following formula (6).
Visceral fat area = −c + (d × fa) + (e × Lf) (6)
In the above formula (6), c to e are constants.

FIG. 9 shows the relationship between the calculated value of the visceral fat area using the above formula (6) and the value of the visceral fat area measured by the CT (Computed Tomography) scanning method, which is generally considered to have high measurement accuracy. FIG. In the present embodiment, as shown in FIG. 9, the calculated value of the internal fat area using the above formula (6) and the visceral fat area measured by the CT scan method have a high correlation coefficient r = 0.907. Is obtained. In addition, the standard error estimation SEE is 24.1 cm ² , and the calculated value using the above equation (6) falls within the range of error 24.1 cm ² , so the correlation with the visceral fat area measured by the CT scan method is I understand that it is expensive. Therefore, according to the estimation method using the above equation (6), it is possible to estimate with high accuracy by using the values of the subcutaneous fat thickness Lf and the body fat mass fa as parameters.

In addition, the control unit 44 converts the subcutaneous fat thickness Lf of the subject to be measured, the body fat mass fa, and the height of the subject to be saved in the memory 42 into a calculation formula for the built-in fat amount saved in the memory 42. By substituting, the amount of visceral fat is obtained. The calculation formula of the visceral fat mass is expressed by the following formula (7).
Visceral fat mass = f + (g x fa) + (h x height)-(i x Lf) (7)
In the above formula (7), f to i are constants.

  FIG. 10 is a correlation diagram showing the relationship between the calculated value of visceral fat mass using the above equation (7) and the value of visceral fat mass measured by the CT scan method. In this embodiment, as shown in FIG. 10, the calculated value of the visceral fat amount using the above equation (7) and the visceral fat amount measured by the CT scan method have a high correlation coefficient r = 0.852. Is obtained. In addition, the standard error estimation SEE is 365.1 g, and the calculated value using the above equation (7) is within the range of 365.1 g of error, so that the correlation with the visceral fat amount measured by the CT scan method is high. I understand. Therefore, according to the estimation method using the above equation (7), it is possible to estimate with high accuracy by using the values of subcutaneous fat thickness Lf, body fat mass fa, and height as parameters.

Further, the control unit 44 obtains the subcutaneous fat area by substituting each of the subcutaneous fat thickness Lf and the body fat mass fa of the measurement subject into the calculation formula of the subcutaneous fat area stored in the memory 42. The calculation formula of the subcutaneous fat area is expressed by the following formula (8).
Subcutaneous fat area = j + (k x fa) + (l x Lf) (8)
In the above formula (7), j to l are constants.

FIG. 11 is a correlation diagram showing the relationship between the calculated value of the subcutaneous fat area using the above equation (8) and the value of the subcutaneous fat area measured by the CT scan method. In this embodiment, as shown in FIG. 11, the calculated value of the subcutaneous fat area using the above equation (8) and the subcutaneous fat area measured by the CT scan method have a high correlation coefficient r = 0.955. Is obtained. Also, the standard error estimation SEE is 18.0 cm ² , and the calculated value using the above equation (8) falls within the range of error 18.0 cm ^2. I understand that it is expensive. Therefore, according to the estimation method using the above equation (8), it is possible to estimate with high accuracy by using the values of the subcutaneous fat thickness Lf and the body fat mass fa as parameters.

Further, the control unit 44 obtains the subcutaneous fat mass by substituting the subcutaneous fat thickness Lf, the body fat mass fa, and the height of the measurement subject into the calculation formula of the subcutaneous fat mass stored in the memory 42. . The calculation formula of the subcutaneous fat mass is expressed by the following formula (9).
Subcutaneous fat mass = m + (n × fa) + (o × height) + (p × Lf) (9)
In the above formula (9), m to p are constants.

FIG. 12 is a correlation diagram showing the relationship between the calculated value of the subcutaneous fat mass using the above equation (9) and the value of the subcutaneous fat mass measured by the CT scan method. In the present embodiment, as shown in FIG. 12, the calculated value of the subcutaneous fat mass using the above equation (9) and the subcutaneous fat mass measured by the CT scan method have a high correlation coefficient r = 0.957. Is obtained. In addition, the standard error estimation SEE is 221.34 g, and the calculated value using the above equation (9) is within the range of the error 221.34 g, so that the correlation with the amount of subcutaneous fat measured by the CT scan method is high. I understand. Therefore, according to the estimation method using the above equation (9), highly accurate estimation is possible by using the subcutaneous fat thickness Lf, the body fat mass fa, and the height value as parameters.
As described above, the control unit 44 determines the body of the subject based on the information related to the subject's obesity (for example, the body weight, the body fat percentage fp, and the body fat mass fa) and the subcutaneous fat thickness Lf of the subject. It functions as a body composition index measurement unit for obtaining an index relating to composition (for example, a built-in fat area, a built-in fat mass, a subcutaneous fat area, and a subcutaneous fat mass).

  When the process of step S5 in FIG. 3 is completed, the control unit 44 determines the various results obtained as described above (body fat percentage fp, body fat mass fa, subcutaneous fat thickness Lf, visceral fat area, visceral fat mass, subcutaneous The display unit 22 is controlled to display the fat area and the subcutaneous fat mass (step S6 in FIG. 3). Thereby, a series of operation | movement is complete | finished.

  As described above, in the present embodiment, when the first measurement electrode 12 (12a, 12b, 12c, 12d) is in contact with the human body, there is a difference in how the phase difference occurs between the fat layer and the muscle layer. Focusing on the fact that there is a current flowing through a current path from one of the first current application electrode 12a and the second current application electrode 12b to the other electrode through the human body, Based on the phase difference from the voltage measured by the voltage measuring unit 30, the subcutaneous fat thickness Lf between the first current application electrode 12a and the second current application electrode 12b is obtained.

  More specifically, the muscle layer has the property of easily causing a phase difference, while the fat layer has the property of hardly causing a phase difference. Therefore, as the subcutaneous fat thickness Lf increases, the property of the fat layer is dominant. Thus, the phase difference becomes smaller, and the smaller the subcutaneous fat thickness Lf, the more dominant the properties of the muscle layer and the larger the phase difference. Then, the ratio of the reactance X to the resistance R decreases as the subcutaneous fat thickness Lf increases, and the ratio of the reactance X to the resistance R increases as the subcutaneous fat thickness Lf decreases. Using this relationship, in the present embodiment, the ratio (R / X) of reactance X and resistance R is obtained, and the value of the obtained ratio is substituted into the above equation (5), so that the corresponding subcutaneous fat is obtained. The thickness Lf is determined. According to this aspect, there is an advantage that the subcutaneous fat thickness Lf can be accurately measured.

  In the present embodiment, the first current application electrode 12a and the second current application electrode 12b are sandwiched between the first voltage measurement electrode 12c and the second voltage measurement electrode 12d. Thus, the first voltage measuring electrode 12c and the second voltage measuring electrode 12d are sandwiched between the first current applying electrode 12a and the second current applying electrode 12b. Compared to (hereinafter referred to as “proportional”), the distance L between the first current application electrode 12a and the second current application electrode 12d can be reduced. In general, there is a variation in how fat is applied to the human body, and the amount of attached fat varies depending on the site (ie, the subcutaneous fat thickness Lf varies), so the first current application for measurement in contact with the human body If the distance L between the electrode for electrode 12a and the second electrode for applying current 12b is large, a measurement error tends to occur. According to the present embodiment, since the distance L between the first current application electrode 12a and the second current application electrode 12d can be made smaller than the proportionality, the subcutaneous fat thickness Lf is measured pinpointly. be able to. For this reason, there is an advantage that the measurement accuracy of the subcutaneous fat thickness Lf is improved as compared with the comparative example.

<C: Modification>
The present invention is not limited to the above-described embodiments, and for example, the following modifications are possible. Also, two or more of the modifications shown below can be combined.

(1) Modification 1
In the above-described embodiment, the subcutaneous fat thickness measurement apparatus 100 has information on obesity such as the subject's weight, body fat percentage fp, and body fat mass fa in addition to the function of measuring the subject's subcutaneous fat thickness Lf. And a function of measuring indices (visceral fat area, visceral fat mass, subcutaneous fat area, subcutaneous fat mass) related to the body composition of the subject by using these measurement results. However, the form of the subcutaneous fat thickness measuring apparatus 100 according to the present invention is not limited to the above-described embodiment, and may be configured to have only a function of measuring the subcutaneous fat thickness Lf, for example.

  FIG. 13 is a diagram showing an appearance of the subcutaneous fat thickness measuring apparatus 100 having only the function of measuring the subcutaneous fat thickness Lf, and FIG. 14 is a block diagram showing a detailed configuration of the subcutaneous fat thickness measuring apparatus 100. . 13 and 14, the configuration of the gripping unit 10 is the same as that of the above-described embodiment. The mounting unit 20 includes a display unit 22, a start key 26d, a first current generation unit 28, a first voltage measurement unit 30, a power supply unit 38, a memory 42, and a control unit 44. 2 The measurement electrode 23 (23a, 23b, 23c, 23d), the weight measurement unit 36, and the like are not provided with means necessary for obtaining the body fat percentage, body weight, and the like of the measurement subject. Similarly, the control unit 44 does not have a function necessary for obtaining the body fat percentage or the body weight of the person to be measured. In addition, when the holding | grip unit 10 is equipped with the structure of the mounting unit 20, the structure that both are integrated can also be employ | adopted.

  FIG. 15 is a flowchart showing the operation of the subcutaneous fat thickness measuring apparatus 100 having only the function of measuring the subcutaneous fat thickness Lf. The operation of the subcutaneous fat thickness measuring apparatus 100 having only the function of measuring the subcutaneous fat thickness Lf will be briefly described with reference to FIG. First, when the start key 26d is turned on by the person to be measured, power supply from the power supply unit 38 is started, and the subcutaneous fat thickness measuring apparatus 100 becomes operable. Then, when the measurement subject presses the distal end portion of the grasping unit 10 against a portion of his / her body where the subcutaneous fat thickness Lf is to be measured, the control unit 44 performs the first method in the same manner as in the above-described embodiment. The subcutaneous fat thickness Lf between the current applying electrode 12a and the second current applying electrode 12b is measured (step S1). When the process of step S2 ends, the control unit 44 controls the display unit 22 to display the subcutaneous fat thickness Lf obtained in step S2 (step S2). As a result, a series of operations are completed.

(2) Modification 2
In the above-described embodiment, the first current application electrode 12a and the second current application electrode 12b are sandwiched between the first voltage measurement electrode 12c and the second voltage measurement electrode 12d. However, the present invention is not limited to this. For example, the first voltage measurement electrode 12c and the second voltage measurement electrode 12d are connected to the first current application electrode 12a and the second voltage measurement electrode 12a. It can also be set as the aspect pinched | interposed between the electrodes 12b for electric current application.

(3) Modification 3
In the above-described embodiment, the distance L in the Y direction between the first current application electrode 12a and the second current application electrode 12b is set to 5 mm, but the distance L is not limited to this. It can be arbitrarily set within a range of 2 mm to 20 mm. In short, the distance L may be a value that can accurately measure the subcutaneous fat thickness Lf.
Also, the distance in the Y direction between the first current application electrode 12a and the first voltage measurement electrode 12c, and the distance between the second current application electrode 12b and the second voltage measurement electrode 12d. Each of the distances in the Y direction is also set to 5 mm. However, the distance is not limited to this, and the distance can be arbitrarily set within a range of 2 mm to 30 mm. In short, the distance in the Y direction between the current application electrode and the voltage measurement electrode only needs to be a value that can accurately measure the impedance of a part of the human body in contact with the measurement electrode.

(4) Modification 4
In the above-described embodiment, an example in which the subcutaneous fat thickness Lf is obtained based on the reactance X and the resistance R is illustrated, but the embodiment is not limited thereto. FIG. 16 is a diagram illustrating the relationship among impedance, reactance X, resistance R, and phase difference. In FIG. 16, the impedance is expressed as Z, and the phase difference is expressed as phase.
As can be understood from FIG. 16, it can be expressed as R = (Z ² −X ² ) ^1/2 , so R / X in the above formula (5) is {(Z / X) ² −1}. Can be transformed to ^1/2 . That is, the subcutaneous fat thickness preservation Lf can be determined according to the value of Z / X.
Further, as can be understood from FIG. 16, since X = (Z ² −R ² ) ^1/2 , R / X in the above formula (5) is 1 / {(Z / R). ² −1} can be modified to ^1/2 . That is, the subcutaneous fat thickness maintenance Lf may be determined according to the value of Z / R.
In short, the subcutaneous fat thickness Lf can be obtained based on the impedance Z and the reactance X, and the subcutaneous fat thickness Lf can be obtained based on the impedance Z and the resistance R.

  Further, it can be expressed as phase difference phase = arctan (R / X). When measuring the human body, the value of impedance Z and the value of resistance R are almost equal, so it can also be expressed as phase difference phase≈arctan (Z / X). FIG. 17 is a diagram showing the relationship between the phase difference phase and the subcutaneous fat thickness Lf, and the subcutaneous fat thickness Lf can also be obtained based only on the phase difference phase.

  Further, the subcutaneous fat thickness Lf can be obtained using two impedance Z values having different frequencies. When the frequency is changed in bioimpedance measurement, the locus of the value of impedance Z draws a known Cole-Cole plot. That is, if two impedance Z values having different frequencies are obtained, the size of the circle of the Cole-Cole plot can be estimated. Here, when the frequency changes, the values of impedance Z, reactance X, resistance R, and phase difference phase change, but R / X is constant.

  FIG. 18 is a diagram illustrating a relationship between the ratio of two impedances Z having different frequencies and R / X. In FIG. 18, as an example, the relationship between the ratio (Z250 / Z50) of the impedance Z250 obtained using the frequency of 250 kHZ and the impedance Z50 obtained using the frequency of 50 KHZ and R / X is shown. Yes. FIG. 19 is a diagram showing the relationship between the ratio of two impedances Z having different frequencies (here, Z250 / Z50) and the subcutaneous fat thickness Lf. As can be understood from FIGS. 18 and 19, it is also possible to obtain the subcutaneous fat thickness Lf based on two impedance Z values having different frequencies.

(5) Modification 5
In the above-described embodiment, the subcutaneous fat thickness measurement apparatus 100 measures the visceral fat area, the visceral fat mass, the subcutaneous fat area, and the subcutaneous fat mass as indices relating to the body composition. The thickness measuring device 100 only needs to measure at least one of the visceral fat area, the visceral fat mass, the subcutaneous fat area, and the subcutaneous fat mass. In this aspect, the measurement subject can specify a desired index, or at least one predetermined index may be measured.

(6) Modification 6
In the above-described embodiment, the subject himself / herself uses the subcutaneous fat thickness measuring apparatus 100, but the present invention is not limited to this, and a user other than the subject (for example, a caregiver) measures the subject's subcutaneous fat thickness Lf. May be.

DESCRIPTION OF SYMBOLS 10 ... Grasping unit, 12a ... 1st current application electrode, 12b ... 2nd current application electrode, 12c ... 1st voltage measurement electrode, 12d ... 2nd voltage measurement electrode, 20 …… Place unit, 22 …… Display section, 23a …… Third current applying electrode, 23b …… Fourth current applying electrode, 23c …… Third voltage measuring electrode, 23d …… First 4 voltage measuring electrodes, 26... Input section, 28... First current generating section, 30... First voltage measuring section, 32... Second current generating section, 34. ...... Weight measurement unit, 38 ... Power supply unit, 42 ... Memory, 44 ... Control unit, 100 ... Subcutaneous fat thickness measurement device.

Claims (9)

A first current application electrode, a second current application electrode, a first voltage measurement electrode, and a second voltage measurement electrode, each of which is a measurement electrode for making contact with a human body for measurement;
A current generator that outputs an alternating current flowing between the first current application electrode and the second current application electrode;
The first voltage measurement electrode disposed adjacent to the first current application electrode, and the second voltage measurement electrode disposed adjacent to the second current application electrode A voltage measuring unit for measuring the voltage between
When the measurement electrode comes into contact with the human body, the current electrode flows from one of the first current application electrode and the second current application electrode through the human body to the other electrode. Subcutaneous fat thickness for determining the subcutaneous fat thickness between the first current application electrode and the second current application electrode based on the phase difference between the current and the voltage measured by the voltage measurement unit A measurement unit,
Subcutaneous fat thickness measurement device. The subcutaneous fat thickness measuring unit is based on an impedance calculated from a current flowing through the current path and a voltage measured by the voltage measuring unit, and a reactance and resistance obtained from the phase difference, and the subcutaneous fat is measured. Find the thickness,
The subcutaneous fat thickness measuring apparatus according to claim 1. The subcutaneous fat thickness measurement unit obtains a ratio between the reactance and the resistance, and determines a subcutaneous fat thickness corresponding to the value of the obtained ratio.
The subcutaneous fat thickness measuring apparatus according to claim 2. The subcutaneous fat thickness determined by the subcutaneous fat thickness measurement unit is a larger value as the ratio of the reactance to the resistance is smaller, and a smaller value as the ratio of the reactance to the resistance is larger.
The subcutaneous fat thickness measuring apparatus according to claim 3. The subcutaneous fat thickness measurement unit is based on the impedance calculated from the current flowing through the current path and the voltage measured by the voltage measurement unit, and the reactance obtained from the impedance and the phase difference, Find the subcutaneous fat thickness,
The subcutaneous fat thickness measuring apparatus according to claim 1. The subcutaneous fat thickness measurement unit is based on the impedance calculated from the current flowing through the current path and the voltage measured by the voltage measurement unit, and the resistance obtained from the impedance and the phase difference, Find the subcutaneous fat thickness,
The subcutaneous fat thickness measuring apparatus according to claim 1. The first current application electrode and the second current application electrode are disposed so as to be sandwiched between the first voltage measurement electrode and the second voltage measurement electrode.
The subcutaneous fat thickness measuring apparatus according to any one of claims 1 to 6. The first current application electrode, the second current application electrode, the first voltage measurement electrode, and the second voltage measurement electrode are arranged along a first direction, and the first current application electrode, The distance in the first direction between the current application electrode and the second current application electrode is the width in the first direction of the first voltage measurement electrode and the second voltage measurement electrode. Smaller than the sum of the width in the first direction at
The subcutaneous fat thickness measuring apparatus according to claim 7. An obesity information measuring unit that measures information on obesity of the measurement subject;
The body composition of the subject based on the subject's subcutaneous fat thickness measured by the subcutaneous fat thickness measurement unit and the information on the subject's obesity measured by the obesity information measurement unit A body composition index measurement unit for obtaining an index; and
The subcutaneous fat thickness measuring apparatus according to any one of claims 1 to 8.

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