JP2022111550A - Deep part body temperature estimation device, deep part body temperature estimation method, and deep part body temperature estimation program - Google Patents

Abstract

To accurately estimate a deep part body temperature of a person to be measured.SOLUTION: A deep part body temperature estimation device includes: a first measuring unit 1 for measuring a heart rate or a pulse rate of a person to be measured; a second measuring unit 2 for measuring a temperature in the vicinity of the person to be measured; a third measuring unit 3 for measuring humidity in the vicinity of the person to be measured; an amount-of-heat calculation unit 12 for calculating an amount of heat that flows into and outflows from deep parts of a first body part and a second body part, and the skin of the person to be measured on the basis of the heart rate or the pulse rate of the person to be measured, the temperature in the vicinity of the person to be measured, and the humidity in the vicinity of the person to be measured; and a temperature calculation unit 11 for calculating a skin temperature and a deep part temperature of the person to be measured on the basis of the amount of heat.SELECTED DRAWING: Figure 1

Description

The present invention relates to a core body temperature estimation device, a core body temperature estimation method, and a core body temperature estimation program for estimating the core body temperature of a person to be measured.

In recent years, many people have been transported by ambulance due to heat stroke, and the total number of people transported by ambulance due to heat stroke nationwide from May to September 2019 was 71,317 (see Non-Patent Document 1). It is said that measurement of core body temperature is effective for diagnosis of heat stroke and reduction of the risk of heat stroke (see Non-Patent Document 2).

In order to monitor core body temperature, it is necessary to measure rectal temperature, bladder temperature, esophageal temperature, etc., and it is difficult to carry out these measurements in daily life. Therefore, as a method of estimating the core body temperature, a method of simply estimating the core body temperature from the heart rate of the person to be measured and the air temperature of the atmosphere has been proposed (see Patent Document 1).

However, the method disclosed in Patent Literature 1 has a problem that the accuracy of estimating core body temperature is low.

JP 2020-65823 A

“2019 (May to September) emergency transportation due to heatstroke”, Ministry of Internal Affairs and Communications, [searched March 31, 2020], <https://www.fdma.go.jp/disaster/heatstroke/items /heatstroke_geppou_2019.pdf＞ “Heat Stroke Treatment Guidelines 2015”, Japanese Association for Acute Medicine, 2015, [searched on March 31, 2019], <https://www.mhlw.go.jp/file/06-Seisakujouhou-10800000- Iseikyoku/heatstroke2015.pdf＞

The present invention has been made to solve the above problems, and provides a core body temperature estimation device, a core body temperature estimation method, and a core body temperature estimation program capable of estimating the core body temperature of a person to be measured with higher accuracy than ever before. intended to

A core body temperature estimating device of the present invention includes a first measuring unit configured to measure the heart rate or pulse rate of a measurement subject, and a second measurement unit configured to measure the temperature in the vicinity of the measurement subject. a measurement unit, a third measurement unit configured to measure the humidity near the measurement subject, the heart rate or pulse rate of the measurement subject, the temperature near the measurement subject, and the measurement subject a heat amount calculation unit configured to calculate the amount of heat flowing into and out of the deep part and skin of the first and second parts of the measurement subject based on the humidity in the vicinity of the measurement subject, and based on the heat amount, and a temperature calculator configured to calculate the skin temperature and the deep temperature of the person to be measured.

Further, in one configuration example of the core body temperature estimating device of the present invention, the first part is the trunk of the measurement subject, the second part is the extremities of the measurement subject, and the calorie calculation is performed. a calorific value calculation unit configured to calculate calorific value of each of the trunk and extremities due to exercise of the measurement subject based on the heart rate or pulse rate of the measurement subject; First heat exchange between the skin and the outside air in each of the trunk and extremities of the measurement subject based on the temperature in the vicinity of the measurement subject and the skin temperature calculated immediately before by the temperature calculation unit a first heat exchange amount calculation unit configured to calculate the amount of A second heat exchange amount calculation unit configured to calculate a second heat exchange amount between the deep part and the skin in each of the trunk and extremities of the measurement subject, and the temperature calculated immediately before by the temperature calculation unit. a third heat exchange amount calculation unit configured to calculate a third heat exchange amount between the trunk and the extremities in the deep part of the person to be measured based on the skin temperature and the deep temperature obtained from the measurement. It is characterized by

Further, in one configuration example of the core body temperature estimating device of the present invention, the first heat exchange amount calculation unit calculates the first heat exchange amount in consideration of the ratio of the skin of the measurement subject covered with clothes. is characterized by calculating
In one configuration example of the core body temperature estimating apparatus of the present invention, the heat amount calculation unit calculates the temperature near the measurement subject, the humidity near the measurement subject, and the skin temperature calculated immediately before by the temperature calculation unit. The method further includes a skin transpiration amount calculation unit configured to calculate a skin transpiration amount in each of the trunk and the extremities of the measurement subject based on the temperature and the deep temperature. be.
Further, in one configuration example of the core body temperature estimating device of the present invention, the heat amount calculation unit is configured to set a fourth heat exchange amount between outside air and the deep part of the measurement subject. and the skin temperature and deep temperature calculated immediately before by the temperature calculating unit, the metabolic rate of the trunk skin layer, the metabolic rate of the trunk deep layer, and the metabolism of the extremities skin layer of the measurement subject. and a metabolic rate calculation unit configured to calculate the metabolic rate of the deep layers of the extremities.

In one configuration example of the apparatus for estimating core body temperature according to the present invention, the temperature calculator may calculate heat generation amounts Q _1,U and Q _1,L of the trunk and extremities of the measurement subject, First heat exchange amounts Q _3,U , Q _3,L between the skin and the outside air in the trunk and extremities, respectively, and between the deep part and the skin in the trunk and extremities, respectively, of the measurement subject the second heat exchange amounts Q _6,U and Q _{6 ,L} , the third heat exchange amount Q between the trunk and the extremities in the deep part of the measurement subject, the trunk of the measurement subject and the Skin transpiration amounts Q _4,U , Q _4,L in each of the extremities, fourth heat exchange amount Q ₅ between the outside air and the deep part of the measurement subject, metabolism amount Q ₂ of the trunk skin layer of the measurement subject _,US , the metabolic rate in the deep layers of the trunk Q _2,UC , the metabolic rate in the skin layers of the extremities Q _2,LS , the metabolic rate in the deep layers of the extremities Q _2,LC , and the heat capacity of the trunk skin layers of the measurement subject. WC _US , heat capacity of the core deep layer WC _UC , heat capacity of the extremity skin layer WC _LS , heat capacity of the extremity deep layer WC _LC , estimated value T _US [t] of the temperature of the trunk skin layer calculated immediately before, body _Time ( _t + _Δt ), estimated trunk skin layer temperature T _US [t+Δt], trunk deep layer temperature T _UC [t+Δt], extremity skin layer temperature estimate T _LS [t+Δt], extremity deep It is characterized by calculating an estimated layer temperature value T _LC [t+Δt].

Further, the core body temperature estimation method of the present invention includes a first step of measuring a heart rate or a pulse rate of a measurement subject, a second step of measuring a temperature near the measurement subject, and a temperature near the measurement subject. and a third step of measuring the humidity of the measurement subject, based on the heart rate or pulse rate of the measurement subject, the temperature near the measurement subject, and the humidity near the measurement subject, the first a fourth step of calculating the amount of heat that flows into and out of the site, the deep part of the second part, and the skin; and a fifth step of calculating the skin temperature and the deep temperature of the person to be measured based on the amount of heat. It is characterized.
Further, a core body temperature estimating program of the present invention is characterized by causing a computer to execute each of the steps described above.

According to the present invention, not only the heart rate of the person to be measured and the temperature in the vicinity of the person to be measured but also the humidity in the vicinity of the person to be measured are measured, and Since the amount of heat flowing into and out of the device is calculated, and the core body temperature of the measurement subject is estimated from the calculated body temperature, the core body temperature can be estimated with higher accuracy than in the past.

FIG. 1 is a block diagram showing the configuration of a core body temperature estimation device according to an embodiment of the present invention. FIG. 2 is a diagram showing a two-part, two-layer model of the subject's body and the amount of heat flowing into and out of each part and each layer of the subject. FIG. 3 is a flow chart for explaining the operation of the core body temperature estimating device according to the embodiment of the present invention. FIG. 4 is a block diagram showing a configuration example of a computer that realizes a core body temperature estimation device according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a core body temperature estimation device according to an embodiment of the present invention. The core body temperature estimating device includes a first measuring unit 1, a second measuring unit 2, a third measuring unit 3, a calorific value calculating unit 4, a metabolic rate calculating unit 5, and a heat transfer/heat radiation calculating unit 6. (first heat exchange amount calculation unit), skin transpiration amount calculation unit 7, exhalation transpiration amount setting unit 8 (fourth heat exchange amount setting unit), heat exchange amount calculation unit 9 (second heat exchange amount calculation unit ), a heat exchange amount calculator 10 (third heat exchange amount calculator), and a temperature calculator 11 .

A calorific value calculator 4, a metabolic rate calculator 5, a heat transfer/thermal radiation rate calculator 6, a skin transpiration rate calculator 7, an exhaled transpiration rate setting section 8, a heat exchange rate calculator 9, and a heat exchange rate calculator 10 constitutes the calorie calculator 12 .

The first measurement unit 1 measures the heart rate or pulse rate of the person to be measured. The first measurement unit 1 is composed of, for example, a wear-type or belt-type electrocardiograph that measures the electrocardiogram of the person to be measured, and a calculation unit that calculates the heart rate from the electrocardiogram measured by the electrocardiograph. . Alternatively, the first measurement unit 1 includes a wristwatch-type or earphone-type pulse wave meter that measures the pulse wave of the person to be measured, and a calculation unit that calculates the heart rate (pulse rate) from the pulse wave measured by the pulse wave meter. consists of

The second measuring unit 2 measures the temperature in the vicinity of the person to be measured (air temperature of the person to be measured). The second measuring unit 2 is composed of, for example, a thermometer. Alternatively, the second measurement unit 2 may acquire weather data near the person to be measured from an external weather system.

The third measuring unit 3 measures the humidity in the vicinity of the person to be measured (humidity of the atmosphere of the person to be measured). The third measurement unit 3 is configured by, for example, a hygrometer. Alternatively, similarly to the second measurement unit 2, the third measurement unit 3 may acquire weather data in the vicinity of the person to be measured from an external weather system.

The first measurement unit 1, the second measurement unit 2, and the third measurement unit 3 may be an integrated measuring device or separate measuring devices.

Based on the heart rate of the measurement subject, the temperature in the vicinity of the measurement subject, and the humidity in the vicinity of the measurement subject, the calorie calculation unit 12 calculates Calculate the amount of heat that flows into and out of the deep part of the body and the skin.
The temperature calculation unit 11 calculates the skin temperature and the deep temperature of the person to be measured based on the heat quantity calculated by the heat quantity calculation unit 12 .

[Method for Estimating Core Body Temperature: Method for Calculating Changes in Core Body Temperature at Each Time Step]
In the present invention, as shown in FIG. 2, the body of the person to be measured is composed of two parts, the trunk U and the extremities L, and the two parts of the trunk U and the extremities L are the deep layer C and the skin layer S, respectively. is considered to have two layers of That is, the body of the measurement subject is composed of a trunk deep layer UC, a trunk skin layer US, a limb deep layer LC, and a limb skin layer LS. The present invention calculates the amount of heat that flows into and out of each part and layer of the person to be measured, based on the obtained temperature, humidity and heart rate information, and calculates the amount of heat that changes from time to time.・Estimate the temperature change in each layer.

In this embodiment, a method for calculating changes in core body temperature for each time step of acquiring sensor data will be described. In this embodiment, as described above, a calculation example is described in which the body of the person to be measured is considered to be composed of two parts, the trunk and the limbs, but the trunk is replaced with the upper body, The limbs may be replaced with the lower body. That is, the body of the person to be measured may be composed of arbitrary two parts, the first part and the second part.

Equations (1) to (4) show the temperature change in the trunk skin layer US, the temperature change in the trunk deep layer UC, the temperature change in the limb skin layer LS, and the temperature in the limb deep layer LC, respectively. Examples of formulas for estimating change are shown. T _US [t] is the temperature [°C] of the trunk skin layer US at time t, T _UC [t] is the temperature [°C] of the deep trunk layer UC at time t, and T _LS [t] is the extremities at time t. The temperature [° C.] of the skin layer LS, and T _LC [t] is the temperature [° C.] of the deep extremity layer LC at time t.

Q _1,U is the calorific value [W] of the trunk U due to the exercise of the measurement subject, and Q _1,L is the calorific value [W] of the extremities L due to the exercise. Q2 _,US is the metabolic rate of the trunk skin layer US [W] of the measurement subject, Q2 _,UC is the metabolic rate of the deep trunk layer UC [W], and Q2 _,LS is the metabolism of the extremity skin layer LS Amount [W], Q _2,LC is the metabolic amount [W] of the limb deep layer LC. Q _3,U (first heat exchange amount) is the amount of heat transfer/heat radiation [W] between the skin and the outside air in the trunk U of the person to be measured, and Q _3,L (first heat exchange amount) is the extremities L is the amount of heat transfer/heat radiation [W] between the skin and the outside air in .

Q _4,U is the amount of skin transpiration in the trunk U of the measurement subject, and Q _4,L is the amount of skin transpiration in the extremities L. Q ₅ (fourth heat exchange amount) is the expiratory transpiration amount [W] of the person to be measured. Q _6,U (second heat exchange amount) is the heat exchange amount [W] between the deep part of the trunk U of the measurement subject and the skin, and Q _6,L (second heat exchange amount) is the deep part and It is the amount of heat exchange [W] between skins. Q ₇ (third heat exchange amount) is the heat exchange amount [W] between the trunk and limbs in the deep part of the person to be measured.

WC _US is the heat capacity of the body trunk skin layer US [J/°C], WC _UC is the heat capacity of the deep trunk layer UC [J/°C], and WC _LS is the heat capacity of the extremity skin layer LS [J/°C]. ], WC _LC is the heat capacity of the extremity deep layer LC [J/°C]. Δt is a calculation step time, and is set to 1 [s] or less, for example.
Also, the average skin temperature T _sk [t+Δt] and core body temperature T[t+Δt] at time t+Δt are given by equations (5) and (6).

sf_conf_US is the ratio [%] of the surface area of the trunk U to the entire body surface of the subject, and sf_conf_LS is the ratio [%] of the surface area of the extremities L to the entire body surface. The heat capacities WC _US , WC _UC , WC _LS , WC _LC and the ratios sf_conf_US, sf_conf_LS are known values, and may be set to values that are practically applicable, and may be appropriately set in the execution of calculations.

FIG. 3 is a flow chart for explaining the operation of the core body temperature estimating device of this embodiment. The first measurement unit 1 measures the heart rate of the person to be measured (step S100 in FIG. 3). The second measuring unit 2 measures the temperature in the vicinity of the person to be measured (the ambient temperature of the person to be measured) (step S101 in FIG. 3). The third measuring unit 3 measures the humidity in the vicinity of the person to be measured (humidity of the atmosphere of the person to be measured) (step S102 in FIG. 3).

[Calculation of calorific value Q ₁ due to exercise]
Next, based on the heart rate measured by the first measuring unit 1, the calorific value calculation unit 4 calculates the calorific value Q _1,U [W] in the deep layer of the trunk U due to the exercise of the measurement subject, The calorific value Q _1,L [W] in the deep layer of the extremities L is calculated by the equations (7) and (8) respectively (step S103 in FIG. 3).

Equations (7) and (8) are derived from the document ““Exercise guidelines for health promotion 2006-For prevention of lifestyle-related diseases-”, Ministry of Health, Labor and Welfare, 2006, <https://www.mhlw.go. jp/shingi/2006/07/dl/s0719-3c.pdf>”. weight is the weight [kg] of the person to be measured, ex_conf_U is the ratio [%] of the muscle mass of the trunk U to the whole body of the person to be measured, and ex_conf_L is the ratio [%] of the muscle mass of the extremities L to the whole body. The weight weight and the ratios ex_conf_U and ex_conf_L are known values, and may be set according to the actual situation, and may be appropriately set in the execution of the calculation.

METs[t] represents the number of METs. The calorific value calculation unit 4 uses the heart rate HR [t] [bpm] at time t acquired by the first measurement unit 1, the resting heart rate HR _rest , and the maximum heart rate HR _max to calculate equation (9) or equation METs[t] may be calculated by any one of the equations (10).

Equation (10) is disclosed in the document JR Wicks, et al., “HR Index-A Simple Method for the Prediction of Oxygen Uptake,” Medicine and Science in Sports and Exercise, 2011.
The resting heart rate HR _rest and the maximum heart rate HR _max may each be known values obtained from past measurements, and may be set as appropriate for actual calculations. Also, for METs[t] used in equations (7) and (8), not only the instantaneous value but also the time average value (for example, the average value for 6 minutes) may be used.

[Calculation of metabolic rate _Q2 ]
Next, the metabolic rate calculation unit 5 calculates the estimated average skin temperature T _sk [t] [° C.] of the measurement subject at time t and the estimated core body temperature T [ t] [°C], the metabolic rate Q _2,US [W] in the trunk skin layer US, the metabolic rate Q _2,UC [W] in the deep trunk layer UC, and the extremity skin layer The metabolic rate Q _2,LS [W] of the LS and the metabolic rate Q _2,LC [W] of the deep layer LC of the extremities are respectively calculated by the formulas (11) to (14) (step S104 in FIG. 3).

Equations (11) to (14) are based on the document “Ronald J Spiegel, “A Review of Numerical Models for Predicting the Energy Deposition and Resultant Thermal Response of Humans Exposed to Electromagnetic Fields”, IEEE Transactions on Microwave Theory and Techniques, Volume 32, Issue 8, 1984. A _skin is a constant related to metabolism, volume_US is the volume of the trunk skin layer US of the measurement subject [m ³ ], volume_LS is the volume of the extremity skin layer LS [m ³ ], and weight_U is the weight of the trunk U of the measurement subject. [kg], weight_L is the weight [kg] of the extremities L. The constant A _skin , the volumes volume_US and volume_LS, and the weights weight_U and weight_L are known values, and may be set as appropriate in the execution of the calculation, using values that are practical.

T _sk [0] is the initial value when calculating the average skin temperature T _sk [t], and T[0] is the initial value when calculating the core body temperature T[t]. In this embodiment, the initial value T _US [0] of the temperature of the trunk skin layer US, the initial value T _UC [0] of the temperature of the deep trunk layer UC, and the initial value T _LS [0] of the temperature of the extremity skin layer LS are used. 0], and as the initial value T _LC [0] of the temperature of the extremity deep layers LC, a realistic value such as an actual value measured by another thermometer or a known value at general rest is used. Therefore, in the initial calculation of the metabolic rate Q ₂ at time t=0, T _sk [t]=T _sk [0].

Similarly, as the initial value T[0] of the core body temperature T[t], a realistic value such as an actual value measured by another temperature measuring device or a known value at general rest is used. Therefore, in the initial calculation of the metabolic rate Q ₂ at time t=0, T[t]=T[0].
Also, the metabolic rate calculator 5 calculates M in the equations (12) and (14) as in the equation (15).

Formula (15) is disclosed in the document "AA Ganpule, et al., "Interindividual variability in sleeping metabolic rate in Japanese subjects", European Journal of Clinical Nutrition, volume 61, 2007". weight_C is the deep weight [kg] of the measurement subject, height is the height [cm] of the measurement subject, and age is the age of the measurement subject. sexcoef is a constant that is 0.5473 when the measurement subject is male and 0.5473×2 when the measurement subject is female. activity_level is a physical activity level, and A _coef is a parameter for metabolic adjustment. The weight weight_C, height height, age age, constant sexcoef, activity_level, and parameter A _coef are known values, and may be set appropriately in the execution of the calculation, using values that match the actual situation.

As an example of setting activity_level, if the person to be measured spends most of his/her life in a sitting position and mainly engages in static activities, the activity_level may be set to about 1.5. If the person to be measured works mainly in a sitting position, but includes movement within the workplace, work in a standing position, customer service, etc., or includes any of commuting, shopping, housework, light sports, etc., Activity_level should be about 1.75. If the person to be measured is engaged in a job that requires a lot of movement or standing, or if he/she has a habit of active exercise in leisure such as sports, activity_level should be set to about 2.0. Thus, the activity_level may be appropriately set according to the exercise status of the person to be measured.

[Calculation of heat transfer/thermal radiation _Q3 between skin and outside air]
Next, the heat transfer/heat radiation amount calculation unit 6 calculates the temperature _Ta [t] [°C] in the vicinity of the person to be measured measured by the second measurement unit 2, and the temperature calculation unit 11 calculated Δt before, Estimated value T _sk [t] [° C.] of average skin temperature of measurement subject at time t, estimated value T US [t] [° C.] of skin layer of body trunk US, and estimated value T _US [t] [° C.] of skin layer of limbs at time t Based on the estimated temperature value T _LS [t] [° C.], the amount of heat transfer/heat radiation Q _3,U [W] between the skin and the outside air in the torso U of the measurement subject, and the skin and heat radiation in the extremities L A heat transfer/heat radiation amount Q _3,L [W] between outside air is calculated (step S105 in FIG. 3). When the second measuring unit 2 measures the temperature _Ta [t] [°C] outside the clothes of the measurement subject, the heat transfer/heat radiation amounts Q _3,U and Q _3,L are expressed by the formula (16) and the formula ( 17).

The ratios sf_conf_US and sf_conf_LS are as described above. fcl_US is a constant representing the efficiency of heat transfer by clothes on the trunk U, fcl_LS is a constant representing the efficiency of heat transfer by clothes on the extremities L, and coverage is the proportion [%] of the extremities L covered by the clothes. The ratios sf_conf_US, sf_conf_LS, the constants fcl_US, fcl_LS, and the ratio coverage are known values, and values that are practical may be used. The constants fcl_US, fcl_LS, and the ratio coverage may be appropriately set according to the clothes of the person to be measured.

HS is the heat exchange coefficient [W/°C] with the air of the person to be measured. The heat transfer/heat radiation amount calculator 6 calculates the heat exchange coefficient HS [W/° C.] using Equation (18).

sf is the body surface area [m ² ] of the subject. The heat transfer/heat radiation amount calculator 6 can calculate the body surface area sf [m ² ] from the weight [kg] and the height [m] of the person to be measured. As a formula for calculating the body surface area sf [m ² ], there are estimation formulas such as the DuBois formula and the Fujimoto formula.

H _cm is the convective heat transfer coefficient [W/°C/m ² ], and H _r is the radiant heat transfer coefficient [W/°C/m ² ]. The heat transfer/heat radiation amount calculator 6 calculates the convective heat transfer coefficient H _cm [W/°C/m ² ] and the radiative heat transfer coefficient H _r [W/°C/m ² ] using the equations (19) and ( 20).

Formulas (19) and (20) are disclosed in the document "D. Fiala, et al., "A computer model of human thermoregulation for a wide range of environmental conditions: the passive system", Journal of Applied Physiology, 1985". It is V _air is wind velocity [m/s]. The heat transfer/heat radiation amount calculation unit 6 may use an actual value measured by an anemometer or the like as the wind speed V _air [m/s]. value may be used.

When the second measurement unit 2 measures the temperature _Ta [t] [°C] in the clothes of the person to be measured, the heat transfer/heat radiation amount calculation unit 6 calculates the heat transfer/heat radiation amount Q _3,U , Q _3,L is calculated by the formulas (21) and (22).

[Calculation of skin transpiration Q ₄ ]
Next, the skin evaporation calculation unit 7 calculates the temperature T a [t] [°C] near the measurement subject measured by the second measurement unit 2 and the temperature T _a [t] [°C] near the measurement subject measured by the third measurement unit 3 The relative humidity humidity [t], the estimated average skin temperature T _sk [t] [°C] and the estimated core body temperature T [t] [°C] at time t calculated before Δt by the temperature calculation unit 11 Based on, the amount of skin transpiration Q _4,U [W] in the trunk U of the measurement subject and the amount of skin transpiration Q _4,L [W] in the extremities L of the measurement subject are calculated by equations (23) and (24), respectively. (Step S106 in FIG. 3).

sw_conf_US is the ratio [%] of the amount of perspiration of the trunk U to the entire body surface of the subject, and sw_conf_LS is the ratio [%] of the amount of perspiration of the extremities L to the entire body surface. Each of the ratios sw_conf_US and sw_conf_LS is a known value, and a practical value may be used, and may be appropriately set in the execution of the calculation. sw is the skin transpiration amount [W] of the whole body. The skin transpiration amount calculation unit 7 can calculate the skin transpiration amount sw [W] by Equation (25).

min(E, E _max ) means to adopt the smaller one of E and E _max . E is the sum [W] of insensible transpiration and sensible transpiration in the skin of the person to be measured. The skin transpiration amount calculator 7 can calculate the sum E [W] of the insensible transpiration and the sensible transpiration according to the equation (26).

PI is the insensible transpiration [W] in the skin of the subject to be measured, and Q _ev is the heat of evaporation of water [J/g]. The insensible evaporation PI [W] and the heat of evaporation Q _ev [J/g] are known values. swrate is sensible transpiration [g/min]. The skin transpiration amount calculator 7 can calculate the perceptible transpiration swrate [g/min] by the equation (27).

Equation (27) is disclosed in the document “D. Fiala, et al., “Computer prediction of human thermoregulatory and temperature responses to a wide range of environmental conditions”, International Journal of Biometeorology, volume 45, 2001”. aij,bij (i = 1, 2, j = 0, 1) are perspiration coefficients. The perspiration coefficients aij and bij are known values, and actual values may be used according to the ease of perspiration of the person to be measured, and may be appropriately set in the execution of the calculation. Specifically, perspiration coefficients aij and bij may be set as shown in equation (28) according to three levels of low (hard to perspire), normal (normal), and high (easy to perspire). .

On the other hand, E _max is the maximum heat of vaporization [W]. In the skin transpiration calculation unit 7, the second measurement unit 2 measures the temperature T _a [t] [°C] outside the clothing of the measurement subject, and the third measurement unit 3 measures the relative humidity humidity outside the clothing of the measurement subject. When measuring [t], the maximum heat of vaporization E _max [W] can be calculated by equation (29).

In the skin transpiration calculation unit 7, the second measurement unit 2 measures the temperature _Ta [t] [°C] in the clothing of the measurement subject, and the third measurement unit 3 measures the relative temperature in the clothing of the measurement subject. When measuring the humidity humidity [t], the maximum heat of vaporization E _max [W] can be calculated by Equation (30).

The ratios sw_conf_US, sw_conf_LS and coverage are as described above. fpcl_US is a constant representing the efficiency of heat transfer by clothes on the trunk U of the measurement subject, _{fpcl_LS} is a constant representing the efficiency of heat transfer by clothes on the extremities L, and _{Emax_coef} is a constant relating to the maximum heat of vaporization. The constants fpcl_US, _{fpcl_LS} , and _{Emax_coef} are known values, and may be set as appropriate in actual calculations.

H _c is heat transfer [W·m ² /° C.] due to convection that depends on air velocity. The skin transpiration amount calculator 7 can calculate the heat transfer H _c [W·m ² /° C.] by Equation (31).

Equations (29) to (31) are disclosed in the document “I.Laakso, et al., “Dominant factors affecting temperature rise in simulations of human thermoregulation during RF exposure”, Physics in Medicine and Biology, Volume 56, 2011”. It is P _s is the saturated water vapor pressure [kPa] in the skin layer of the person to be measured. The skin transpiration amount calculator 7 can calculate the saturated water vapor pressure P _s [kPa] by the equation (32).

_Pa is the saturated water vapor pressure [kPa] in the atmosphere whose humidity is being measured. The skin transpiration amount calculation unit 7 can calculate the saturated water vapor pressure P _a [kPa] by the equation (33).

[Determination of expiratory transpiration _Q5 ]
Next, the exhaled transpiration amount setting unit 8 sets the transpiration amount Q ₅ [W] due to the exhaled breath of the person to be measured as shown in Equation (34) (step S107 in FIG. 3). The expiratory transpiration amount Q ₅ [W] corresponds to the amount of heat exchange between the outside air and the depth of the subject.

[Calculation of heat exchange amount Q ₆ between deep part and skin]
Next, the heat exchange amount calculation unit 9 calculates the heart rate HR [t] [bpm] measured by the first measurement unit 1 and the trunk skin layer US at time t calculated by the temperature calculation unit 11 before Δt. Estimated temperature T _US [t] [°C], estimated temperature T _UC [t] [°C] of core deep layer UC, and estimated temperature of extremity skin layer LS T _LS [t] [°C] ], the estimated temperature of the limb deep layer LC T _LC [t] [°C], the estimated average skin temperature T _sk [t] [°C], and the estimated core body temperature T [t] [°C] Based _{on the} formula ( 35), and calculated by equation (36) (step S108 in FIG. 3).

The ratios sf_conf_US and sf_conf_LS are as described above. hx is the heat exchange coefficient between the skin of the person to be measured and the deep part. The heat exchange amount calculation unit 9 can calculate the heat exchange coefficient hx by Equation (37).

METs[t] is as described above. a, b, e, hx0, hx1, and hx_max are parameters related to heat exchange coefficients. The parameters a, b, e, hx0, hx1, and hx_max are known values, and may be set appropriately through experiments.

[Calculation of heat exchange amount _Q7 between trunk and extremities]
Next, the heat exchange amount calculation unit 10 calculates the estimated value T _UC [t] [°C] of the temperature of the trunk deep layer UC at time t, which was calculated by the temperature calculation unit 11 before Δt, and the temperature of the extremities deep layer LC. Based on the temperature T _LC [t] [° C.], the estimated average skin temperature T _sk [t] [° C.], and the estimated core body temperature T [t] [° C.], A heat exchange amount Q ₇ [W] between U and extremities L is calculated by equation (38) (step S109 in FIG. 3).

hcc is the heat exchange coefficient between the trunk U and the extremities L in the deep part of the person to be measured. The heat exchange amount calculation unit 10 can calculate the heat exchange coefficient hcc by Equation (39).

f and hcc0 are parameters related to the heat exchange coefficient. The parameters f and hcc0 are known values, and may be set appropriately through experiments. hcc_T is the temperature contribution of the heat exchange coefficient hcc, and hcc_M is the METs contribution of the heat exchange coefficient hcc. The heat exchange amount calculation unit 10 can calculate the temperature contribution hcc_T of the heat exchange coefficient hcc by Equation (40).

hcc_Tmax is the specified upper limit of hcc_T. Also, the heat exchange amount calculation unit 10 can calculate the METs contribution hcc_M of the heat exchange coefficient hcc by using the equation (41).

hcc_Mmax is the specified upper limit of hcc_M. hcc1 is a parameter related to the heat exchange coefficient. The upper limit values hcc_Tmax, hcc_Mmax, and the parameter hcc1 are known values, and may be set appropriately through experiments. aveMETs[t] is the time average value of the METs number (for example, the average value for 6 minutes). Parameters a and b are as described above.

In this way, the calorific value calculator 4, the metabolic rate calculator 5, the heat transfer/thermal radiation amount calculator 6, the skin transpiration rate calculator 7, the exhaled transpiration rate setting section 8, the heat exchange rate calculator 9, and the heat exchange rate calculator 10, each heat quantity Q1 _,U , Q1 _,L , Q2 _,US , Q2 _,UC , Q2 _,LS , Q2 _,LC , Q3 _,U , Q3 _,L , Q4 _,U , Q4 _,L , _Q5 , Q6 _,U , Q6 _,L , _Q7 can be calculated.

The temperature calculation unit 11 calculates an estimated value T _US [t] [° C.] of the temperature of the trunk skin layer US of the measurement subject at time t, the metabolic rate Q _2,US [W] of the trunk skin layer US, Heat transfer/thermal radiation amount Q _3,U [W] between the skin and the outside air in the trunk U, skin transpiration amount Q _4,U [W] in the trunk U, and heat between the deep part and the skin in the trunk U Based on the amount of exchange Q _6,U [W], an estimated value T _US [t+Δt] [° C.] of the temperature of the trunk skin layer US after Δt is calculated by Equation (1) (step S110 in FIG. 3).

The temperature calculation unit 11 calculates an estimated value T _UC [t] [°C] of the temperature of the deep layer UC of the measurement subject at time t, and an amount of heat generation Q _1,U [W] , the metabolic rate Q _2,UC [W] in the core deep layer UC, the expiratory transpiration rate Q ₅ [W], the heat exchange rate Q _6,U [W] between the deep region and the skin in the core U, and the deep region Based on the heat exchange amount Q ₇ [W] between the trunk U and the extremities L at the time, the estimated value T _UC [t + Δt] [°C] of the temperature of the trunk deep layer UC after Δt is calculated by the formula (2) Calculate (step S111 in FIG. 3).

The temperature calculation unit 11 calculates an estimated value T _LS [t] [°C] of the temperature of the extremity skin layer LS of the measurement subject at time t, the metabolic rate Q _2,LS [W] of the extremity skin layer LS, Heat transfer/thermal radiation Q _3,L [W] between the skin and the outside air in the extremities L, skin transpiration Q _4,L [W] in the extremities L, and heat between the deep part and the skin in the extremities L Based on the replacement amount Q _6,L [W], the estimated value T _LS [t+Δt][° C.] of the temperature of the extremity skin layer LS after Δt is calculated by Equation (3) (step S112 in FIG. 3).

The temperature calculator 11 calculates an estimated value T _LC [t] [°C] of the temperature of the deep layers LC of the limbs L of the measurement subject at time t, and the amount of heat generated Q _1,L [W] in the deep layers of the limbs L. , the metabolic rate Q _2,LC [W] of the limb deep layer LC, the heat exchange rate Q _6,L [W] between the deep part and the skin in the limb L, and the deep part between the trunk U and the limb L Based on the amount of heat exchange Q ₇ [W], an estimated value T _LC [t+Δt] [° C.] of the temperature of the extremity deep layer LC after Δt is calculated by Equation (4) (step S113 in FIG. 3).

Thus, temperature estimates T _US [t+Δt], T _UC [t+Δt], T _LS [t+Δt], and T _LC [t+Δt] can be calculated sequentially.
Then, the temperature calculation unit 11 calculates the estimated value T _sk [t+Δt][° C.] of the average skin temperature after Δt using the formula (5) (step S114 in FIG. 3). Further, the temperature calculation unit 11 calculates the estimated value T[t+Δt][° C.] of the core body temperature after Δt using the equation (6) (step S115 in FIG. 3).

The core body temperature estimating apparatus performs the above steps S100 to S115 every cycle Δt. In the next calculation after Δt, T _US [t + Δt], T _UC [t + Δt], T _LS [t + Δt], T _LC [t + Δt], T _sk [t + Δt], T [t + Δt] calculated in the previous calculation are T _US [t], T _UC [t], T _LS [t], T _LC [t], T _sk [t], and T [t], respectively, and steps S100 to S115 may be performed. .

In this embodiment, not only the heart rate of the person to be measured and the temperature in the vicinity of the person to be measured, but also the humidity in the vicinity of the person to be measured is measured, and the amount of heat flowing into and out of each part and each layer of the person to be measured is calculated. Since the deep body temperature of the measurement subject is estimated from the calculated amount of heat, the deep body temperature can be estimated with higher accuracy than in the past.

In addition, although the present embodiment describes the case of using the heart rate of the person to be measured, the pulse rate may be used instead of the heart rate.

The calorific value calculator 4, the metabolic rate calculator 5, the heat transfer/thermal radiation amount calculator 6, the skin transpiration rate calculator 7, the exhaled transpiration rate setting section 8, the heat exchange rate calculator 9, and the heat exchange rate of the present embodiment The calculation unit 10 and the temperature calculation unit 11 can be implemented by a computer having a CPU (Central Processing Unit), a storage device, and an interface, and a program that controls these hardware resources. A configuration example of this computer is shown in FIG.

The computer comprises a CPU 200 , a storage device 201 and an interface device (I/F) 202 . The I/F 202 is connected with the first measuring section 1, the second measuring section 2, the third measuring section 3, and the like. In such a computer, a core body temperature estimation program for implementing the core body temperature estimation method of the present invention is stored in the storage device 201 . The CPU 200 executes the processing described in this embodiment according to the programs stored in the storage device 201 . It is also possible to provide the program through a network.

In addition, a calorific value calculator 4, a metabolic rate calculator 5, a heat transfer/thermal radiation amount calculator 6, a skin transpiration rate calculator 7, an exhaled transpiration rate setting section 8, a heat exchange rate calculator 9, and a heat exchange rate calculator 10 and the temperature calculator 11 may be distributed among a plurality of computer devices.

INDUSTRIAL APPLICABILITY The present invention can be applied to techniques for estimating core body temperature of the human body.

DESCRIPTION OF SYMBOLS 1... 1st measurement part, 2... 2nd measurement part, 3... 3rd measurement part, 4... Calorific value calculation part, 5... Metabolic amount calculation part, 6... Heat transfer and heat radiation amount calculation part, 7... Skin transpiration Quantity calculation unit 8: Evaporation amount setting unit 9: Heat exchange amount calculation unit 10: Heat exchange amount calculation unit 11: Temperature calculation unit 12: Heat amount calculation unit.

Claims (8)

a first measuring unit configured to measure the heart rate or pulse rate of the person to be measured;
a second measuring unit configured to measure the temperature in the vicinity of the person to be measured;
a third measuring unit configured to measure the humidity in the vicinity of the person to be measured;
based on the heart rate or pulse rate of the measurement subject, the temperature near the measurement subject, and the humidity near the measurement subject; a heat amount calculation unit configured to calculate the amount of heat flowing into and out of the
A core body temperature estimating device, comprising: a temperature calculator configured to calculate a skin temperature and a core temperature of the person to be measured based on the amount of heat. The core body temperature estimating device according to claim 1,
The first part is the trunk of the measurement subject,
The second part is the extremities of the measurement subject,
The heat quantity calculation unit
a calorific value calculation unit configured to calculate calorific value of each of the trunk and extremities due to exercise of the measurement subject based on the heart rate or pulse rate of the measurement subject;
First heat exchange between the skin and the outside air in each of the trunk and extremities of the measurement subject based on the temperature in the vicinity of the measurement subject and the skin temperature calculated immediately before by the temperature calculation unit a first heat exchange amount calculation unit configured to calculate the amount of
Based on the heart rate or pulse rate of the measurement subject and the skin temperature and deep temperature calculated immediately before by the temperature calculation unit, A second heat exchange amount calculation unit configured to calculate a second heat exchange amount of
A third heat exchange amount between the trunk and the extremities in the deep part of the measurement subject is calculated based on the skin temperature and the deep temperature calculated immediately before by the temperature calculation unit. 3. A core body temperature estimating device, comprising: a heat exchange amount calculating unit; The core body temperature estimating device according to claim 2,
The deep body temperature estimating device, wherein the first heat exchange amount calculation unit calculates the first heat exchange amount in consideration of a ratio of clothing covering the skin of the person to be measured. The core body temperature estimating device according to claim 2 or 3,
The calorie calculation unit calculates the above-described A core body temperature estimating device, further comprising a skin transpiration amount calculator configured to calculate a skin transpiration amount in each of the trunk and the extremities. The core body temperature estimating device according to claim 4,
The heat amount calculation unit includes a fourth heat exchange amount setting unit configured to set a fourth heat exchange amount between the outside air and the deep part of the person to be measured;
Based on the skin temperature and the deep temperature calculated immediately before by the temperature calculating unit, the metabolic rate of the trunk skin layer, the metabolic rate of the trunk deep layer, the metabolic rate of the extremity skin layer, and the extremities of the measurement subject. A core body temperature estimating device, further comprising: a metabolic rate calculation unit configured to calculate a metabolic rate in a deep layer. The core body temperature estimating device according to claim 5,
The temperature calculation unit
Heat generation amounts Q _1,U , Q _1,L of the trunk and extremities of the measurement subject, and first heat exchange amounts between the skin and the outside air of the trunk and extremities of the measurement subject, respectively Q _3,U , Q _3,L , second heat exchange amounts Q _6,U , Q _6,L between deep parts and skin in the trunk and extremities of the subject, respectively; A third heat exchange amount Q ₇ between the trunk and the extremities in the deep part, skin transpiration amounts Q _4,U , Q _4,L in the trunk and the extremities of the measurement subject, respectively, outside air and the above Fourth deep heat exchange amount Q ₅ of the measurement subject, metabolic rate Q _2,US of the trunk skin layer of the measurement subject, metabolic rate Q _2,UC of the deep trunk layer of the measurement subject, metabolism of the extremity skin layer amount Q _2,LS , metabolic rate Q _2,LC in the deep layers of the extremities, heat capacity WC _US of the trunk skin layers of the measurement subject, heat capacity WC _UC of the deep trunk layers, heat capacity WC _LS of the skin layers of the extremities, The heat capacity of the limb deep layer WC _LC , the estimated value T _US [t] of the temperature of the trunk skin layer calculated immediately before, the estimated value of the temperature of the trunk deep layer T _UC [t], and the temperature of the limb skin layer Based on the estimated value T _LS [t] and the estimated value T _LC [t] of the temperature of the limb deep layer,

At time (t+Δt), the estimated trunk skin layer temperature T _US [t+Δt], the trunk deep layer temperature T _UC [t+Δt], and the limb skin layer temperature estimated T _LS [t+Δt ], and an estimated value T _LC [t+Δt] of the temperature of the deep layers of the extremities. a first step of measuring the heart rate or pulse rate of the person to be measured;
a second step of measuring the temperature in the vicinity of the person to be measured;
a third step of measuring the humidity in the vicinity of the person to be measured;
based on the heart rate or pulse rate of the measurement subject, the temperature near the measurement subject, and the humidity near the measurement subject; A fourth step of calculating the amount of heat flowing into and out of
and a fifth step of calculating the skin temperature and the core temperature of the subject based on the amount of heat. 8. A deep body temperature estimating program that causes a computer to execute each step according to claim 7.

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