JP2000237146A - Stress measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a high-precision estimated stress value in a stress measuring device. SOLUTION: This stress measuring device is provided with a stress load system 1, measuring units 2-4 measuring multiple physiological quantities of a human body, and a stress measuring circuit 5. The stress measuring circuit 5 is provided with index value derivation sections 7-9 deriving multiple index values from multiple physiological quantities, a single regression equation calculation section 10 applying a regression analysis to the index values with explanatory variables and the subjective declared values of stresses used as objective variables, a memory 13 storing grouped results of multiple testees based on multiple correlation coefficients obtained on multiple indexes, a memory 14 storing stress estimating equations for sorted groups, an attribute group calculation section 12 judging the group to which a measurement subject belongs based on multiple correlation coefficients on multiple indexes obtained by the single regression equation calculation section 10, and a stress calculation section 15 substituting multiple index values on the measurement subject into the stress estimating equation on the judged group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stress measuring device for quantitatively measuring the degree of stress such as a feeling of tension or a monotonous feeling.

[0002]

2. Description of the Related Art Conventionally, the degree of stress has been evaluated for the purpose of utilizing it for human health management and labor management. For example, a decrease in skin temperature at a peripheral part such as a fingertip of a human body has been performed. It is known that the amount is measured and the reduced amount is used as an evaluation value of the degree of stress. However, there is an individual difference in the amount of decrease in skin temperature due to the stress load, and there is a problem that the accuracy of the evaluation value is extremely low because this individual difference is not taken into account in the evaluation.

Therefore, the present inventors have found that the temperature difference between the nose skin temperature and the forehead skin temperature can be an index that accurately represents the stress level, and a stress measurement device that estimates the stress level based on the index. (Eg, Japanese Patent Laid-Open No. 9-2)
8678, JP-A-8-252226, etc.). According to the device, a quantitative evaluation value with higher accuracy than before can be obtained by taking into account individual differences regarding stress.

[0004]

However, even with the above-described stress measuring device, individual differences relating to stress are still an error factor in stress estimation, and there is room for improvement in stress estimation accuracy. For example, when subjected to stress, the difference between peripheral skin temperature and trunk skin temperature changes according to the stress level, and a correlation is seen between the stress level and the skin temperature. It varies from person to person, with a high correlation giving a more accurate estimate of stress,
An error occurs in the estimation of the degree of stress. Also, regarding the sensitivity of skin temperature when subjected to stress, there is also an individual difference, targeting a human body whose skin temperature response is insensitive, even when estimating the degree of stress based only on skin temperature, high accuracy is high. No estimate is obtained.

It is an object of the present invention to provide a stress measuring device capable of obtaining a stress estimation value with higher accuracy.

[0006]

Accordingly, the present inventors conducted various stress-loading experiments on a plurality of subjects to examine the relationship between various physiological quantities of the human body and the degree of stress when subjected to stress. As a result, the physiological amount that responds sensitively when subjected to stress varies from person to person, and one physiological amount, for example, a subject whose skin temperature response is insensitive, can respond to other physiological amounts such as heart rate. Found that it was possible to categorize subjects into multiple groups, with multiple subjects sharing a common physiological quantity sensitive to stress as one group. The invention has been completed.

[0007] A stress measuring device according to the present invention comprises a stress applying means capable of applying stress to a human body, a physiological quantity measuring means for measuring a plurality of physiological quantities of a human body in a stress applied state, An index value deriving unit that performs necessary arithmetic processing on a plurality of measured physiological quantities and derives a plurality of index values to be changed according to the degree of the received stress, and for each index, the index value is calculated. The regression analysis is performed using the explanatory variable, the subjective report value of the degree of the received stress as the objective variable, and a regression analysis means for obtaining a correlation coefficient and a regression equation, and based on a plurality of correlation coefficients obtained for a plurality of indexes. A grouping result storage means in which results of classifying a plurality of subjects having similar correlations between each index and stress as one group are stored, and a plurality of index values for each classified group are stored. Stress A stress estimation formula storing means in which a stress estimation formula for determining is stored, and a human body to be subjected to stress measurement, based on a plurality of correlation coefficients for a plurality of indices obtained by the regression analysis means, Group determining means for determining a group to which a human body belongs;
Substituting a plurality of index values for the human body into the stress estimation formula for the group determined by the group determination means,
Stress estimating means for calculating an estimated value of the stress level.

When measuring the degree of stress using the stress measuring apparatus of the present invention, first, as a preparation, stress is applied to a human body to be subjected to stress measurement by using a stress applying means. Then, a plurality of physiological quantities are measured by the physiological quantity measuring means under the stress load state.
For example, as the physiological amount, the skin temperature of the peripheral part and the trunk part of the human body, the number of heartbeats per unit time, the number of blinks, and the like can be adopted. In addition, the subject is made to report the subjective stress level received by the subject in each stress load state, and a subjective report value is obtained.

[0009] The measured physiological quantity is sent to index value deriving means, where necessary arithmetic processing is performed on the required physiological quantity, and a plurality of index values are derived. As the index value, for example, the difference in skin temperature between the peripheral part and the trunk part, the number of heartbeats per unit time, the number of blinks per unit time, and the like can be used.

The derived index values and subjective report values of the stress level are supplied to regression analysis means, and regression analysis is performed for each index. As a result, for each metric,
A regression equation representing the relationship between the index value and the subjective report value, and a correlation coefficient are obtained. The plurality of correlation coefficients obtained for the plurality of indices are sent to the group-by-group determining means, and the group to which the measurement subject belongs is determined. For example, a measurement subject having a large correlation coefficient for skin temperature is determined to be classified into a group of subjects having a high correlation coefficient for skin temperature.

Thereafter, a plurality of index values for the measurement subject are substituted into the stress estimation formula for the group to which the measurement subject belongs, and an estimated value of the stress degree is calculated. Here, the stress estimation formula for the group to which the subject belongs to includes a plurality of index values as variables, and among them, an index that responds sensitively when the subject is stressed Since a large coefficient is applied, the estimated value of the stress degree is highly accurate reflecting the physiological response of the measurement subject to the stress.

As a method for classifying subjects into a plurality of groups, for example, a method of performing a cluster analysis on a plurality of correlation coefficients obtained for a plurality of indices for a plurality of subjects may be employed. I can do it. by this,
Objective classification becomes possible. In this case, the group-based determination unit plots one point determined by the plurality of correlation coefficients obtained by the regression analysis unit on a multidimensional space having the correlation coefficient of each index as each axis, and The group in which the distance (Euclidean distance) between the point and the farthest point belonging to each group is the shortest can be determined as the group to which the human body belongs. This method is known as a method of selecting a group having the shortest distance from a certain point, and is generally called a furthest neighbor method, but employs various other methods such as a nearest neighbor method and a Ward method. You can do it.

More specifically, the stress estimation formula stored in the stress estimation formula storage means stores the index value in the regression equation for each index of each subject obtained by the regression analysis means for each of the classified groups. It is obtained by performing multiple regression analysis using a plurality of correction index values derived by substituting as explanatory variables and a subjective report value of the degree of stress received as an objective variable, and is obtained by performing multiple stress estimation means. Are converted into correction index values, and then substituted into the stress estimation formula.

According to this specific configuration, a correction index value specific to the subject is input as each of a plurality of index values to be substituted into the stress estimation formula, and the correction index value shows a high correlation with stress. As for the index value, while the index value is given a large weight, the index value showing a low correlation with stress is given a small weight, so that individual differences in the physiological response are sufficiently taken into account. Value. Therefore, the estimated value of the stress degree obtained based on the correction index value has high accuracy.

[0015]

According to the stress measuring device of the present invention, a highly accurate stress level can be obtained by sufficiently taking into account individual differences in physiological responses in estimating the stress level.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows a configuration of a stress measurement device according to the present invention, in which a transient stress load system (1) for applying a transient stress to a human body and a plurality of physiological quantities under a stress load state. Skin thermometers (2), electrocardiographs (3), and eyeblinkers (4), which are measuring instruments for measuring changes in stress, and stress for estimating the degree of stress based on physiological quantities measured by these measuring instruments It comprises a measuring circuit (5), a printer (16) for outputting the estimated stress level, and a display (17).

The transient stress load system (1) provides a subject with a skin thermometer (2), an electrocardiograph (3) and a blink meter (4).
In a state in which is worn, for example, a predetermined stress is applied to the subject by using a tracking operation of tracking a point moving around on the screen by a mouse operation. The skin thermometer (2) measures the skin temperature of the peripheral part of the subject (for example, the skin temperature of the tip of the nose) and the skin temperature of the trunk (for example, the skin temperature of the forehead).
Is measured. The electrocardiograph (3) measures a subject's heart rate per unit time. The blink meter (4) measures the number of blinks (number of blinks) per unit time of the subject. The specific configuration of the stress measurement circuit (5) will be described later together with its operation.

In measuring the degree of stress using the stress measuring device of the present invention, an experiment for deriving a stress estimation formula is performed in advance. In this case, an experiment is performed on a plurality of subjects (for example, about 20 to 40), but here, for convenience of explanation, an experiment is performed on five subjects (A, B, C, D, and E). Will be described.

Each subject is subjected to a tracking operation including three sessions shown in FIG. 4 using the transient stress load system (1). Each session consists of a resting state (5 minutes), subjective report of stress level (2 minutes), tracking work (10 minutes), and subjective report (2 minutes)
It is composed of At the time of the tracking work in the second session, it is instructed that the work is extended for 90 seconds for each mistake, giving a great sense of tension. However, no extension is actually implemented. In the tracking work of the third session, the user is informed that there is a possibility that some kind of emergency may occur during the tracking work, and gives a moderate sense of tension. However, no emergency has actually occurred. And skin thermometer (2), electrocardiograph (3)
And a blink meter (4) to measure the subject's heart rate, the nose tip and forehead skin temperature, and the number of blinks in each state.
Also, in each state, the subject's subjective reported value of tension (0 to 0)
100) is obtained.

The measurement data from the skin thermometer (2), the electrocardiograph (3) and the eyeblink meter (4) are respectively calculated by the skin system index calculation unit (7) of the stress measurement circuit (5) shown in FIG. It is supplied to a cardiac system index calculation unit (8) and a blink system index calculation unit (9). The skin index calculating section (7) calculates the difference between the skin temperature of the subject's nose and the forehead (hereinafter simply referred to as skin temperature) as an index value. The cardiac system index calculation unit (8) calculates a time average value of the heart rate of the subject (hereinafter, referred to as an average heart rate) as an index value. Further, the blinking index calculating unit (9) calculates the number of blinks per unit time (hereinafter, referred to as a blink rate) as an index value. The subjective report value of the tension (hereinafter, simply referred to as tension) is input to the subjective report value input unit (6) of the stress measurement circuit (5).

Table 1 shows the average heart rate, skin temperature, blink rate, and nervousness of each subject for each experimental condition. In the condition column in the table, "rest: none" is the rest state of the first session, "rest: extended" is the rest state of the second session, "rest: teach" is the rest state of the third session, "rest: teach". “Work: none” indicates the work state of the first session, “work: extension” indicates the work state of the second session, and “work: teach” indicates the work state of the third session.

[0022]

[Table 1]

The subjective report value of tension obtained from the subjective report value input unit (6), the skin system index calculation unit (7), the heart system index calculation unit (8), and the blink system index calculation unit (9), The temperature, average heart rate, and blink rate are calculated by a simple regression equation calculation unit (1 for each index).
0), and a simple regression analysis is performed for each index. As a result, for each subject, the correlation coefficient r for each index and the slope a and intercept b included in the linear regression equation (y = ax + b) are obtained.

FIGS. 5A, 5B, and 5C show three subjects A.
FIGS. 6A, 6B, and 6C show the results of simple regression analysis for the two indices: heart rate, skin temperature, and blink rate.
FIGS. 7A, 7B, and 7C show the results of the simple regression analysis for the three indices of the subject B, and FIGS. 7A, 7B, and 7C show the results of the simple regression analysis for the three indices of the subject C. FIG.
9 (b) and (c) show the results of simple regression analysis on three indices of subject D, and FIGS. 9 (a), (b) and (c) show results of simple regression analysis on three indices of subject E. Is represented. The mathematical formulas described in the figures correspond to each subject i (i =
1 to 5; i = 1 is subject A, i = 2 is subject B, i = 3
Is the subject C, i = 4 is the subject D, i = 5 is the subject E) (j = 1 to 3; j = 1 is the average heart rate, j = 2 is the skin temperature, j = 3 is the blink rate) Linear regression equation (y = a _ij · x
+ B _ij ), and R ² represents the square value of the correlation coefficient r. As is clear from these results, the indices sensitive to stress differ from subject to subject. For example, for subject A, the correlation between the subjective report value of stress and the skin temperature is low, but the subjective report value of stress is low. There is a relatively high correlation between the and the blink rate, and the reaction is relatively sensitive. On the other hand, for the subject E, the correlation between the subjective report value of stress and the blink rate is lower than that of the subject A, but a very high correlation is observed between the subjective report value of stress and the heart rate. The reaction is also sensitive.

Table 2 summarizes the correlation coefficient r, slope a, and intercept b for each index of each subject in a list.

[Table 2]

The correlation coefficient r is subjected to cluster analysis. However, the closer the absolute value of the correlation coefficient r is to 1, the more the distribution is biased toward 1. Therefore, Fisher's Z transformation represented by the following equation 1 is performed. As a result, the distribution of the correlation coefficient approximately becomes a normal distribution. Table 3 shows the result of the Z conversion.

[0027]

## EQU1 ## Z = (1/2) log _e ((1 + r) / (1-r))

[0028]

[Table 3]

In the cluster analysis, for example, as shown in FIG. 11, the correlation coefficients R1, R2, and R3 for three indices are calculated by three.
When points determined by three correlation coefficients of each subject are plotted in the space of the orthogonal coordinate system as an axis, subjects with short distances between the points are taken into the same group, and the subjects are divided into groups. , All the subjects are classified into a plurality of groups G1, G2, G3.
FIG. 10 shows the result of performing a cluster analysis on the correlation coefficient r subjected to the Z conversion shown in Table 3. As shown, subjects A and B are categorized into group 1 and subjects C, D and E are categorized into group 2. The grouping result obtained in this way is stored in the grouping result storage memory (13) shown in FIG. Note that the grouping result includes, for each group, coordinate information for specifying a space area occupied by the group in the orthogonal coordinate system.

Subsequently, a multiple regression analysis is performed for each group of subjects, using three indices (average heart rate u, skin temperature v, blink rate w) as explanatory variables and subjective report value z of stress as an objective variable.
A multiple regression equation of the following equation 2 is obtained for each group.

Group 1: z ₁ = α ₁ u + β ₁ v + γ ₁ w + η ₁ Group 2: z ₂ = α ₂ u + β ₂ v + γ ₂ w + η ₂

Here, as an index serving as an explanatory variable,
, The average heart rate u, the skin temperature v, and the blink rate w
Can be substituted as it is, but the index value is corrected in order to take individual differences in the reactivity of each index when stress is applied. That is, as the correction index value,
The following equation 3 obtained by substituting the index values u, v, w into the regression equation (y = a _ij × x + b _ij ) for each index j of each subject i obtained by the simple regression analysis is adopted. A new multiple regression equation is created using the correction index values u ′, v ′, w ′ as explanatory variables and the subjective report value z of stress as an objective variable.

[0032]

[Equation 3] Average heart rate: u '= _ail · u + _bil Skin temperature: v' = _ai2 · v + bi _i2 blink rate: w '= _ai3 · w + _bi3

Thus, the multiple regression equation for each group is given by
Will be represented by

Group 1: z ₁ '= α ₁ ' u '+ β ₁ ' v '+ γ
₁ 'w' + _{η 1} 'group _{2: z 2' = α 2} 'u' + β 2 'v' + γ 2 'w'
+ Η ₂ ′

Table 4 shows the index values u, v, w for each subject belonging to each group, the slope a and intercept b of the simple regression equation obtained for each index, and the above equation (3). Correction index values u ', v', and w '.

[Table 4] Here, for example, regarding the average heartbeat in the case of the work instruction of the subject E included in the group 2, the corrected average heartbeat u ′ is calculated as follows. u ′ = a ₅₁ · ^u + b ₅₁ = 2.9012 × 84.891-237.98 = 8.306

A multiple regression analysis using the above equation 4 was performed for the group 1 based on the data of the subjects A and B, and for the group 2 based on the data of the subjects C, D and E. The results shown in Table 6 were obtained, and the multiple regression equation shown in the following Expression 5 was described.

[0036]

[Table 5]

[Table 6]

[0037]

Group 1: z ₁ = 0.485u '+ 0.482v'
+ 0.787w'-26.831 Group _{2: z 2 = 0.832u'-0.047v} '+ 0.2
77w′−2.571 From these equations, for group 1, the corrected blink rate is an important variable to explain the tension, and for group 2, the corrected average heart rate is an important variable to explain the tension. You can see that there is.

Therefore, the stress level can be estimated from the three correction index values using the multiple regression equation shown in the above equation (5). These multiple regression equations are stored in the group-based stress estimation equation storage memory (14) shown in FIG. Here, three correction index values, that is, a corrected average heart rate u 'and a corrected skin temperature v'
The corrected blink rate w 'is calculated for each subject using the above equation (3). For example, when stress of the same condition is applied to a plurality of subjects belonging to the same group, even if a certain index value is the same, for a subject to which the index responds sensitively, a subject to which the index is insensitive is considered. The correction index value becomes larger than that, and as far as the index is concerned, the estimated value of the stress level becomes larger, and individual differences are taken into account.

After the above preliminary experiment, the actual stress level is measured using a stress measuring device. First, as a preparation for the stress measurement, a group-based stress estimation formula optimal for the stress measurement target person is derived. FIG. 2 shows the specific procedure.

Using the transient stress load system (1), a series of tracking operations shown in FIG. Then, the subject's heart rate, the skin temperature of the nose tip and forehead, and the number of blinks in each state are measured by a skin thermometer (2), an electrocardiograph (3), and a blink meter (4). In each state, a subjective report value (0 to 100) of a sense of tension is acquired from the measurement subject.

The measurement data from the skin thermometer (2), the electrocardiograph (3) and the eyeblinker (4) are respectively used for the skin system index calculation section (7) of the stress measurement circuit (5) shown in FIG. It is supplied to a cardiac system index calculation unit (8) and a blink system index calculation unit (9). Further, the sense of tension is input to the subjective report value input section (6) of the stress measurement circuit (5).

The unit (10) for calculating a simple regression equation for each index of the stress measurement circuit (5) includes a subjective report value input unit (6), a skin system index calculation unit (7), a heart system index calculation unit (8), Each of the index values, that is, the subjective report value of nervousness, the skin temperature, the average heart rate, and the blink rate are taken in from the blink-system index calculating unit (9), and the representative values of each index at rest and during work are 6 points. Is calculated (steps S1 and S2 in FIG. 2). The calculated representative value of each index is supplied to a calculation unit (10) of a simple regression equation for each index,
A simple regression analysis is performed for each index (step S in FIG. 2).
3). As a result, for the measurement subject, the correlation coefficient r for each index and the slope a and the intercept b included in the linear regression equation (y = ax + b) are obtained. Then, the slope a and the intercept b are supplied to a stress estimation value calculation unit (11) for each index, and the correlation coefficient r is supplied to an attribute group calculation unit (12).

The attribute group calculator (12) assigns the subject to group 1 based on three correlation coefficients r for the three indices obtained from the index-based simple regression equation calculator (10). It is determined whether to classify or to classify into group 2 (step S4 in FIG. 2). In this case, the grouping result storage memory (1
When the grouping result stored in 3) is referred to and points determined by the three correlation coefficients of the measurement subject are plotted in the above-described rectangular coordinate system (see FIG. 11), the existence of group 1 is determined from the points. It is determined which of the Euclidean distance to the space area to be measured and the Euclidean distance from the point to the space area where the group 2 exists is shorter, and the group with the shorter distance is classified into the group to which the person to be measured is classified. Is determined. As the distance of the spatial region, the distance between the point and the point having the maximum value in each group, the distance between the point and the point having the minimum value in each group, the distance between the point and each group, The distance from the center of gravity or the like can be adopted. This determination result is supplied to the group-based stress estimation formula storage memory (14), and the above determination is made from the two stress estimation formulas (Equation 4) stored in the group-based stress estimation formula storage memory (14). A stress estimation formula for a group is selected and read, and a group-specific stress calculator (15)
(Step S5 in FIG. 2).

Thereafter, the degree of stress of the stress measurement subject at any time is measured. FIG. 3 shows the specific procedure.

The skin thermometer (2), the electrocardiograph (3), and the blink meter (4) measure the heart rate, the skin temperature of the nose tip and forehead, and the number of blinks of the subject for stress measurement. The measurement data is supplied to the skin system index calculation unit (7), the heart system index calculation unit (8), and the blink system index calculation unit (9), respectively. Calculation unit (1) of simple regression equation for each index of stress measurement circuit (5)
0) obtains each index value, that is, skin temperature, average heart rate, and blink rate from the skin system index calculation unit (7), the heart system index calculation unit (8), and the blink system index calculation unit (9). Capture (step S11 in FIG. 3). These index values are supplied to a calculation unit (11) of a stress estimation value for each index via a calculation unit (10) of a simple regression equation for each index, and are obtained from the calculation unit (10) of a simple regression equation for each index. Based on the slope a and the intercept b of the obtained simple regression equation, a stress estimation value for each index, that is, correction index values u ', v', w 'is calculated using the above equation (step S12 in FIG. 3). . The result is the group-specific stress calculator (1
5).

Thereafter, the group-by-group stress calculator (15)
The correction index values u ', v', and w 'obtained from the stress estimation value calculation unit (11) are added to the stress estimation expression for the measurement subject read from the group-based stress estimation expression storage memory (14). Then, an estimated stress value is calculated (step S13 in FIG. 3). The calculated stress estimate is provided to a printer (16) and / or a display (17).
And output (step S14 in FIG. 3).
Finally, the measurement procedure is terminated after determining whether or not to terminate the measurement (step S15 in FIG. 3).

In the above embodiment, the tension is used as the subjective amount of stress. However, a monotonous feeling can be used instead of the tension. The same is true. In the above embodiment, for convenience of explanation, the number of subjects is five, and the number of indices is three, that is, skin temperature, heart rate, and blink rate. However, by using a greater number of subjects and indices, A highly accurate stress estimation formula can be derived. For example, as an indicator,
Various physiological quantities such as blood pressure and respiratory rate per unit time can be added. Further, when a larger number of subjects are employed, these subjects can be classified into three or more groups, whereby the accuracy of stress level estimation can be further increased.

FIG. 12 shows estimated stress stress values (0 to 100) calculated by the stress measuring device of the present invention in a plurality of stress loads, with the number of subjects being 30.
6 is a graph showing a correlation between the subject and a self-reported value of anxiety or tension of the subject. Here, 30 subjects
They were categorized into three groups. 13 is a similar graph for 19 subjects included in Group 1, FIG. 14 is a similar graph for 8 subjects included in Group 2, and FIG.
7 is a similar graph for three subjects included in group 3. As is clear from these graphs, according to the stress measuring device of the present invention, it is possible to obtain a highly accurate stress estimation value with respect to feeling of tension and anxiety.

FIG. 16 shows the estimated values (0 to 100) of the monotonous stress calculated by the stress measuring device of the present invention under a plurality of stress loads and the self-reported values of the subject's disgust or malaise. It is a graph showing the correlation. Here, subjects were categorized into four groups. FIG.
Is a similar graph for the subjects included in Group 1, FIG. 18 is a similar graph for the subjects included in Group 2, FIG. 19 is a similar graph for the subjects included in Group 3, and FIG. 9 is a similar graph for subjects included in group 4. As is clear from these graphs,
ADVANTAGE OF THE INVENTION According to the stress measuring device of this invention, about a disgust and anxiety, a highly accurate stress estimation value can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a stress measurement device according to the present invention.

FIG. 2 is a flowchart illustrating a procedure for deriving a group-based stress estimation formula.

FIG. 3 is a flowchart illustrating a procedure for calculating an estimated stress value.

FIG. 4 is a time chart of a tracking operation.

FIG. 5 is a graph showing the results of simple regression analysis for subject A for each index.

FIG. 6 is a similar graph for subject B.

FIG. 7 is a similar graph for subject C;

FIG. 8 is a similar graph for subject D;

FIG. 9 is a similar graph for subject E;

FIG. 10 is a diagram showing a result of cluster analysis.

FIG. 11 is a diagram illustrating a state in which a plurality of subjects are grouped in an orthogonal coordinate system in which correlation coefficients for three indices are three axes.

FIG. 12 is a graph showing a correlation between an estimated stress value and a self-reported value for all subjects.

FIG. 13 is a similar graph for a subject belonging to group 1.

FIG. 14 is a similar graph for a subject belonging to group 2.

FIG. 15 is a similar graph for a subject belonging to group 3.

FIG. 16 is a graph showing a correlation between a monotone stress estimated value for all subjects and a self-reported value thereof.

FIG. 17 is a similar graph for a subject belonging to group 1.

FIG. 18 is a similar graph for a subject belonging to group 2.

FIG. 19 is a similar graph for a subject belonging to group 3.

FIG. 20 is a similar graph for a subject belonging to group 4.

[Explanation of symbols]

 (1) Transient stress load system (2) Skin thermometer (3) Electrocardiograph (4) Blink meter (5) Stress measurement circuit (10) Calculation unit of single regression equation for each index (11) Each index Stress estimation value calculation unit (12) Attribute group calculation unit (13) Grouping result storage memory (14) Group-based stress estimation formula storage memory (15) Group-based stress calculation unit (16) Printer (17) Display

Claims (5)

[Claims] 1. A stress measuring device for measuring a degree of stress applied to a human body, a stress load means for applying a stress to the human body, and measuring a plurality of physiological quantities of the human body in a stress load state. A physiological quantity measuring means; an index value deriving means for performing necessary arithmetic processing on a plurality of measured physiological quantities to derive values of a plurality of indices to be changed according to the degree of stress received; Regression analysis is performed using the index value as an explanatory variable and the subjective report value of the degree of stress received as an objective variable, and a regression analysis means for obtaining a correlation coefficient and a regression equation. A grouping result storage means for storing a result of classifying a plurality of subjects having similar correlations between each index and stress as one group based on the correlation coefficient; A stress estimation formula storing means for storing a stress estimation formula for estimating stress from a plurality of index values; and a plurality of indices obtained by the regression analysis means for a human body to be subjected to stress measurement. Based on a plurality of correlation coefficients, a group determining means for determining a group to which the human body belongs, and a plurality of index values for the human body are substituted into a stress estimation formula for the group determined by the group determining means. ,
A stress measuring device comprising: a stress estimating means for calculating an estimated value of a stress degree. 2. The stress estimation formula stored in the stress estimation formula storage means is obtained by substituting an index value into a regression equation for each index of each subject obtained by the regression analysis means for each group. The obtained multiple corrected index values are explanatory variables, and the subjective report value of the degree of stress received is an objective variable, which is obtained by performing multiple regression analysis, and the stress estimating means includes a plurality of index values. The stress measurement device according to claim 1, wherein each of the stress measurement values is converted into a correction index value, and then substituted into a stress estimation expression. 3. The grouping result storage means stores results obtained by performing cluster analysis on a plurality of correlation coefficients obtained for a plurality of indices for a plurality of subjects and classifying the subjects into a plurality of groups. The stress measuring device according to claim 1 or 2, wherein 4. The group determining means plots a point determined by the plurality of correlation coefficients obtained by the regression analysis means on a multidimensional space having the correlation coefficient of each index as each axis, The stress measurement device according to claim 3, wherein a group having the shortest distance from the point is determined as a group to which the human body belongs. 5. The plurality of physiological quantities to be measured by the physiological quantity measuring means include skin temperature of a peripheral part and a trunk part of a human body, heart rate per unit time and number of blinks, and the index value deriving means includes: 5. The method according to claim 1, wherein a difference in skin temperature between a peripheral part and a trunk part, a heart rate per unit time and a number of blinks are output as index values.
The stress measuring device according to any one of the above.