Deep body temperature estimation device and deep body temperature estimation program

Abstract

To provide a technique capable of improving estimation accuracy of a deep body temperature at the time of bathing.SOLUTION: A deep body temperature estimation device 100 includes a first temperature calculation unit 31, a second temperature calculation unit 32, and a determination unit 33. The first temperature calculation unit 31 calculates a deep body temperature on the basis of a body model for calculating a heat quantity in full bathing. The second temperature calculation unit 32 calculates a deep body temperature on the basis of a heart rate. The determination unit 33 determines the lower one of the deep body temperatures calculated by the first temperature calculation unit 31 and the second temperature calculation unit 32 as an estimated value of the deep body temperature.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a deep body temperature estimation device and a deep body temperature estimation program. [Background technology]

[0002] In recent years, efforts have been made to enable users to bathe in a bathroom in a healthier way by measuring the user's body temperature while bathing and managing the bathing time, etc.

[0003] For example, Patent Document 1 discloses a bathing navigation system that estimates a user's deep body temperature and suggests bathing methods. The bathing navigation system estimates the amount of change in core temperature, which is the bather's current deep body temperature, or the core temperature, based on a detection means for detecting the bathing state and data on the bathing state detected by this detection means. The bathing navigation system suggests comfortable bathing methods to the bather based on the estimated amount of change in core temperature or core temperature. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-174 A Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors of the present application recognized that there is room for improvement in the technology disclosed in Patent Document 1 in terms of improving the accuracy of estimating deep body temperature, since estimation errors occur depending on the user's bathing state, such as moving the body while bathing, when estimating deep body temperature based on heat calculations using a body model and on heart rate.

[0006] An object of the present disclosure is to provide a technique that can improve the accuracy of estimating deep body temperature during bathing. [Means for solving the problem]

[0007] The deep body temperature estimation device disclosed herein includes a first temperature calculation unit that calculates the deep body temperature based on a body model that calculates the amount of heat in a whole-body bath, a second temperature calculation unit that calculates the deep body temperature based on the heart rate, and a determination unit that determines the lower of the deep body temperatures calculated by the first temperature calculation unit and the second temperature calculation unit to be an estimated value of the deep body temperature. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing the overall configuration of a core body temperature estimation device according to an embodiment; [Diagram 2] 1 is a block diagram showing the configuration of a deep body temperature estimation device. [Diagram 3] FIG. 13 is a schematic diagram for explaining a body model for calculating heat quantity in a whole-body bath. [Figure 4] 11 is a graph showing an example of a change in hot water temperature. [Diagram 5] 1 is a graph showing an example of a change in heart rate. [Figure 6] 1 is a graph showing a relationship coefficient of skin blood flow to total blood flow. [Figure 7] 4 is a graph showing an example of a deep body temperature calculated by a second temperature calculation unit. [Figure 8] 13 is a graph showing an example of an estimated deep body temperature. [Figure 9] 13 is a flowchart showing the procedure of a process for estimating a core body temperature. [Figure 10] 1 is a graph showing the relationship coefficient of skin blood flow to total blood flow adjusted at the time of exiting the bath. [Figure 11] 13 is a graph showing an example of a deep body temperature estimated when the correlation coefficient is adjusted. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The following describes the embodiments. The same components are given the same reference numerals, and duplicated descriptions are omitted. In each drawing, some components are omitted, enlarged, or reduced as appropriate for the convenience of description. The drawings should be viewed according to the orientation of the reference numerals. The structures and shapes referred to in this specification include not only structures and shapes that strictly match the shapes referred to, but also structures and shapes that deviate by an amount of error such as dimensional error and manufacturing error. In this specification, "connection," "fixing," "mounting," and "supporting" include cases where the conditions referred to are directly met by two parties, as well as cases where the conditions are met via other members, unless otherwise specified.

[0010] (Embodiment) See Fig. 1. The deep body temperature estimation device 100 is used by a user taking a bath in a bathtub 8, for example. The deep body temperature estimation device 100 estimates the deep body temperature of the user while bathing based on measurement data from a water temperature sensor 11 and an electrocardiogram sensor 12 arranged in the bathtub 8. The water temperature sensor 11 measures the temperature of the water stored in the bathtub 8. The deep body temperature estimation device 100 uses the measurement data from the water temperature sensor 11 to calculate the deep body temperature based on a body model that calculates the amount of heat in a whole-body bath.

[0011] The electrocardiogram sensor 12 measures the electrocardiogram of the user bathing in the bathtub 8 and outputs the user's heart rate. The electrocardiogram sensor 12 can use a method of detecting the electrocardiogram by arranging multiple electrodes in the bathtub 8, for example, and can also serve as a sensor for detecting whether the user is bathing. The deep body temperature estimation device 100 calculates the deep body temperature based on the measurement data from the electrocardiogram sensor 12.

[0012] Please refer to Fig. 2. The deep body temperature estimation device 100 includes an interface unit (hereinafter referred to as I / F unit) 21, an alarm unit 22, a timer unit 23, and a control unit 30. Each unit in the deep body temperature estimation device 100 can be realized in terms of hardware by electronic elements and mechanical parts such as a computer CPU, and in terms of software by a computer program or the like. Here, functional blocks realized by the cooperation of these are depicted. Therefore, it will be understood by those skilled in the art that these functional blocks can be realized in various forms by combining hardware and software.

[0013] The I / F unit 21 receives signal inputs from the connected hot water temperature sensor 11 and electrocardiogram sensor 12, and inputs them to the control unit 30. The timing unit 23 measures time based on instructions from the control unit 30.

[0014] The notification unit 22 has a display unit 22a and an audio output unit 22b. The display unit 22a is configured with, for example, a liquid crystal display, an organic EL (Electro Luminescence) display, an LED (Light Emitting Diode) display, or the like. The display unit 22a displays information such as the user's heart rate, water temperature, and deep body temperature. When the user's deep body temperature estimated by the deep body temperature estimation device 100 is equal to or higher than a predetermined value, the display unit 22a may display a warning to the outside that the deep body temperature has risen too high.

[0015] The audio output unit 22b generates an audio signal and outputs the audio from an output device such as a speaker. The audio output unit 22b outputs information such as the user's heart rate, water temperature, and deep body temperature to the outside by audio. Similar to the display unit 22a, the audio output unit 22b may output an audio warning to the outside that the deep body temperature is rising too much when the user's deep body temperature is equal to or higher than a predetermined value.

[0016] The control unit 30 has a first temperature calculation unit 31, a second temperature calculation unit 32, a determination unit 33, and an operation processing unit 34. The first temperature calculation unit 31 calculates the deep body temperature based on a body model that calculates the amount of heat in a whole-body bath. See FIG. 3. The body model is composed of two nodes, for example, a deep layer and a skin layer. As shown in FIG. 3, the skin layer has a part that is immersed in hot water in a whole-body bath and a part that is in contact with air, and heat transfer between the hot water and the air is taken into consideration.

[0017] In the body model, heat is transferred between the skin layer and the deep layer by blood flow, and heat is generated in the deep layer by metabolism. The first temperature calculation unit 31 calculates the deep body temperature by calculating the amount of heat transferred from outside the skin layer, the heat transfer by blood flow between the skin layer and the deep layer, and the metabolism in the deep layer. The first temperature calculation unit 31 may use the amount of heat transfer based on the skin blood flow rate described later.

[0018] The second temperature calculation unit 32 acquires the user's heart rate from the electrocardiogram sensor 12, and calculates the user's deep body temperature based on a predetermined relational expression between the heart rate and the deep body temperature. There is a correlation between the heart rate and the deep body temperature, and for example, a regression line between the heart rate and the deep body temperature can be obtained by a statistical method. The relationship between the heart rate and the deep body temperature may also be approximated by a curve. The second temperature calculation unit 32 calculates the deep body temperature corresponding to the heart rate based on, for example, the regression line.

[0019] The second temperature calculation unit 32 may change the relational equation between the heart rate and the deep body temperature depending on the season. The second temperature calculation unit 32 may change the relational equation between the heart rate and the deep body temperature depending on the room temperature of the living room, the bathroom, etc. The second temperature calculation unit 32 may use a relational equation that calculates a high deep body temperature so that the estimated value of the deep body temperature of a user with a low heart rate does not become too low.

[0020] In the above body model, if the skin blood flow rate is Vbf, the initial value of the deep body temperature is To, the deep body temperature is Tc, the vasodilation coefficient is Pb, and the constant is C, the following relationship holds: Vbf = C + Pb × (Tc - To) (1) The vasodilation coefficient Pb may be a constant or may be calculated as a function of the hot water temperature (an approximate function such as a linear function). The constant C may be, for example, a value such as 6.3 (L / m 2 / h) depending on the unit system used.

[0021] The second temperature calculation unit 32 can calculate the skin blood flow rate Vbf in the above formula (1) by a function using as variables the change in heart rate, the blood flow rate per heartbeat, the relationship coefficient of the skin blood flow rate to the total blood flow rate (the coefficient indicating the distribution amount to the skin layer), the hot water temperature, time, etc., and can also calculate the deep body temperature using formula (1). The skin blood flow rate Vbf calculated by the second temperature calculation unit 32 can, for example, calculate a result more suitable for the user's bathing situation by changing the relationship coefficient of the skin blood flow rate to the total blood flow rate in the body (the coefficient indicating the distribution amount to the skin layer) during the bathing period and the post-bathing period.

[0022] The determination unit 33 determines the lower of the deep body temperatures calculated by the first temperature calculation unit 31 and the second temperature calculation unit 32 as the estimated value of the deep body temperature. The operation processing unit 34 determines, for example, whether electrocardiogram data has been acquired, and measures the user's bathing time and post-bathing time by measuring time with the timer unit 23. The operation processing unit 34 performs processing to determine operations such as whether to continue estimating the deep body temperature or to initialize it based on the user's bathing time and post-bathing time.

[0023] Refer to FIGS. 4 and 5. FIG. 4 shows the change in hot water temperature when the user bathes in the bathtub at a hot water temperature of 41° C. for 18 minutes, takes a 5-minute post-bathing break, and then bathes again for 5 minutes. The hot water temperature gradually decreases while the user is immersed in the hot water of the bathtub 8, and gradually increases due to supplementary heating by the water heater before the user gets out of the bath. Since the hot water temperature changes during bathing like this, it is desirable to consider the change in hot water temperature for estimating the deep body temperature. As shown in FIG. 5, the user's heart rate changes due to bathing and post-bathing. During the post-bathing period, it is assumed that the user's heart rate is generally constant.

[0024] Please refer to FIG. 6, FIG. 7 and FIG. 8. The coefficient of the relationship between the total blood flow rate and the skin blood flow rate shown in FIG. 6 is assumed to gradually increase from the start of bathing, taking into account the effect of the change in the water temperature as shown in FIG. 4. As shown in FIG. 7, the deep body temperature calculated by the first temperature calculation unit 31 increases over time due to the amount of heat received from the water in the bathtub 8. In FIG. 8, the deep body temperature based on the heart rate calculated by the second temperature calculation unit 32, the deep body temperature estimated by the determination unit 33, and the measured value of the deep body temperature are shown. As described above, the determination unit 33 estimates the deep body temperature based on the lower of the deep body temperatures calculated by the first temperature calculation unit 31 and the second temperature calculation unit 32 at every moment. The second temperature calculation unit 32 calculates the deep body temperature at the next time point based on the deep body temperature estimated by the determination unit 33 at a certain time point.

[0025] Next, the operation of deep body temperature estimation by the deep body temperature estimation device 100 will be described with reference to Fig. 9. The operation processing unit 34 of the deep body temperature estimation device 100 determines whether or not heart rate data has been acquired from the electrocardiogram sensor 12 (S1). If the operation processing unit 34 determines in step S1 that heart rate data has not been acquired (S1: NO), it repeats step S1. If the operation processing unit 34 determines in step S1 that the user's heart rate data has been acquired (S1: YES), it starts measuring the bathing time (S2).

[0026] The first temperature calculation unit 31 acquires data on the heart rate from the electrocardiogram sensor 12 and on the water temperature from the water temperature sensor 11 (S3). The second temperature calculation unit 32 calculates the user's deep body temperature based on the heart rate, for example, using a regression line. The determination unit 33 sets the deep body temperature based on the heart rate calculated by the second temperature calculation unit 32 as an initial value (To) (S4).

[0027] The deep body temperature estimation device 100 continues to acquire data on the heart rate and water temperature (S5). The first temperature calculation unit 31 calculates an estimated value Tca of the deep body temperature change by calculating the heat quantity of the body model (S6). The second temperature calculation unit 32 calculates an estimated value Tcb of the deep body temperature change based on the heart rate (S7). In step S7, the second temperature calculation unit 32 calculates the estimated value Tcb of the deep body temperature change based on equation (1) using a relation coefficient between the skin blood flow rate and the total blood flow rate, etc. The aforementioned judgment unit 33 judges whether the estimated value Tca is greater than the estimated value Tcb (S8).

[0028] If the judgment unit 33 judges in step S8 that the estimated value Tca is greater than the estimated value Tcb (S8: YES), it estimates the deep body temperature to be To+Tcb (S9). If the judgment unit 33 judges in step S8 that the estimated value Tca is greater than the estimated value Tcb (S8: NO), it estimates the deep body temperature to be To+Tca (S10). After steps S9 and S10, the action processing unit 34 judges whether or not the heart rate data has been acquired from the electrocardiogram sensor 12 (S11). If the action processing unit 34 judges in step S11 that the heart rate data has been acquired (S11: YES), it continues measuring the bathing time (S12), and returns to step S5 to repeat the process.

[0029] When the action processor 34 determines in step S11 that the heart rate data has not been acquired (S11: NO), it stops measuring the bathing time (S13) and starts measuring the bathing exit time (S14). The action processor 34 determines whether the bathing exit time is equal to or longer than a predetermined time (S15). The predetermined time is, for example, 20 minutes.

[0030] When the operation processing unit 34 determines that the bath time is not equal to or longer than the predetermined time (S13: NO), it returns to step S11 and repeats the process. When the operation processing unit 34 determines that the bath time is equal to or longer than the predetermined time (S13: YES), it ends the deep body temperature estimation process. In the process from step S6 to step S10, the first temperature calculation unit 31 and the second temperature calculation unit 32 may calculate the deep body temperature estimates To+Tca and To+Tcb, compare them, and the determination unit 33 may determine the lower one as the deep body temperature estimate. Calculating the deep body temperature by the first temperature calculation unit 31 and the second temperature calculation unit 32 and determining the lower one as the deep body temperature is equivalent to obtaining and comparing the estimated values ​​of the deep body temperature change and calculating the deep body temperature based on the lower one.

[0031] After the deep body temperature estimation process is completed, the operation processing unit 34 resumes the deep body temperature estimation process and determines whether or not heart rate data has been acquired from the electrocardiogram sensor 12 (S1). The deep body temperature estimation device 100 initializes the calculation of the deep body temperature by the first temperature calculation unit 31 and the second temperature calculation unit 32, sets the deep body temperature calculated from the heart rate as an initial value, and executes the subsequent processes.

[0032] The deep body temperature estimation device 100 can reduce estimation errors that occur depending on the bathing state of the user and improve the estimation accuracy of the deep body temperature by using the lower of the deep body temperatures calculated by the first temperature calculation unit 31 and the second temperature calculation unit 32 as the estimated value of the deep body temperature. For example, when the user moves his / her hands and feet, the blood flow to the muscles increases and the heart rate increases even if the body temperature does not increase. In this case, the estimated value of the deep body temperature based on the heat amount calculation in the whole body bath by the first temperature calculation unit 31 is lower than the estimated value of the deep body temperature based on the change in the heart rate by the second temperature calculation unit 32. The deep body temperature estimation device 100 can improve the estimation accuracy of the deep body temperature by using the determination unit 33 to use the deep body temperature calculated by the first temperature calculation unit 31 as the estimated value.

[0033] For example, when the user's body is often out of the bath due to a half-body bath, or when the user has repeatedly entered and exited the bath, the deep body temperature estimation device 100 can improve the estimation accuracy of the deep body temperature. When the user's body is often out of the bath, or when the user has repeatedly entered and exited the bath, the body temperature and the heart rate are less likely to rise. The deep body temperature calculated by the second temperature calculation unit 32 reflects the heart rate and is lower than the deep body temperature calculated by the first temperature calculation unit 31, improving the estimation accuracy of the deep body temperature.

[0034] The second temperature calculation unit 32 of the deep body temperature estimation device 100 calculates the skin blood flow rate using a function that includes variables such as the heart rate. As shown in Fig. 6, the second temperature calculation unit 32 can reflect the increase in skin blood flow rate during bathing by changing the relation coefficient of the skin blood flow rate to the total blood flow rate in the function that calculates the skin blood flow rate, thereby improving the estimation accuracy of the deep body temperature.

[0035] When the time to leave the bath measured by the timer 23 has elapsed a predetermined time, the operation processing unit 34 of the deep body temperature estimation device 100 initializes the calculation of the deep body temperature by the first temperature calculation unit 31 and the second temperature calculation unit 32. When the user's body temperature has decreased after a predetermined time has elapsed since leaving the bath, the deep body temperature estimation device 100 can continue to estimate the deep body temperature by estimating the deep body temperature based on the heart rate when re-entering the bath and setting the initial value. If the predetermined time has not yet elapsed since leaving the bath, the operation processing unit 34 continues to calculate the deep body temperature by the first temperature calculation unit 31 and the second temperature calculation unit 32.

[0036] The notification unit 22 of the deep body temperature estimation device 100 may notify the outside that the deep body temperature estimated by the determination unit 33 has reached a predetermined value or more. This allows the deep body temperature estimation device 100 to notify the user that the deep body temperature has risen too high, for example.

[0037] (Modification) See Fig. 10 and Fig. 11. Fig. 10 and Fig. 11, like Fig. 4 in the above embodiment, show graphs of a user bathing in a bathtub with a water temperature of 41°C for 18 minutes, exiting the bath for 5 minutes, and then entering the bath for another 5 minutes. The coefficient of relationship between total blood flow and skin blood flow shown in Fig. 10 is assumed to decrease toward the state before bathing during the exit period. The change in the coefficient of relationship between total blood flow and skin blood flow during the bathing period is assumed to show the same change as the coefficient of relationship described in Fig. 6.

[0038] As shown in Fig. 11, the deep body temperature estimated by the determination unit 33 during the next 5-minute bathing period after exiting the bath is lower than the deep body temperature shown in Fig. 8 and is closer to the measured deep body temperature. The deep body temperature estimation device 100 can further improve the estimation accuracy of the user's deep body temperature by adjusting the relationship coefficient of the skin blood flow rate to the total blood flow rate at the time of exiting the bath so as to decrease it.

[0039] The above describes the embodiments and modifications. When understanding the technical ideas that abstract the embodiments and modifications, the technical ideas should not be interpreted as being limited to the contents of the embodiments and modifications. The above-mentioned embodiments and modifications are merely illustrative examples, and many design changes such as changing, adding, or deleting components are possible. In the embodiments, the contents in which such design changes (for example, detecting the heart rate with a wearable sensor) are possible are emphasized by adding the notation "embodiment". However, design changes are also permitted even in contents without such notation. The hatching on the cross sections of the drawings does not limit the material of the hatched objects.

[0040] Any combination of the above components is also effective as an aspect of the technical idea that abstracts the embodiment and the modified example. For example, any description of another embodiment may be combined with the embodiment, and any description of the embodiment and the modified example may be combined with the modified example. [Explanation of symbols]

[0041] 22...notification unit, 23...timing unit, 31...first temperature calculation unit, 32...first temperature calculation unit, 33...determination unit, 34...notification unit, 100...core body temperature estimation device.

Claims

1. a first temperature calculation unit that calculates a deep body temperature based on a body model that calculates a heat quantity in a whole body bath; A second temperature calculation unit that calculates a deep body temperature based on the heart rate; a determination unit that determines the lower of the deep body temperatures calculated by the first temperature calculation unit and the second temperature calculation unit as an estimated value of the deep body temperature; A deep body temperature estimation device comprising:

2. The deep body temperature estimation device according to claim 1 , wherein the second temperature calculation unit calculates the skin blood flow using a function that includes a heart rate as a variable, and changes a relation coefficient of the skin blood flow to the total blood flow in the function.

3. The deep body temperature estimating device according to claim 2 , wherein the second temperature calculation unit adjusts a coefficient of relationship between skin blood flow and total blood flow when the user exits the bath.

4. Further comprising a timing unit, A deep body temperature estimation device as described in any one of claims 1 to 3, wherein the calculations in the first temperature calculation unit and the second temperature calculation unit are initialized when the time measured by the timing unit has elapsed a predetermined time after leaving the bath.

5. The deep body temperature estimation device according to claim 1 , further comprising an alarm unit that notifies an outside source that the deep body temperature estimated by the determination unit has reached a predetermined value or higher.

6. A deep body temperature estimation program for causing a computer to determine the lower of the deep body temperature calculated based on the heart rate and the deep body temperature calculated based on a body model that calculates the amount of heat in a whole-body bath as an estimated deep body temperature.

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