SE2051171A1

SE2051171A1 - Hot flash mitigation

Info

Publication number: SE2051171A1
Application number: SE2051171A
Authority: SE
Inventors: Anette Gullberg
Original assignee: Mondian Ab
Priority date: 2020-10-07
Filing date: 2020-10-07
Publication date: 2022-04-08
Also published as: EP4193366A1; WO2022075909A1; SE545969C2; EP4193366A4

Abstract

A therapeutic system comprising a sensing arrangement configured to sense a first property indicative of sweat gland activity, and a second property indicative of a body temperature; a heat-controlling arrangement for controlling heat flux from the body; and control circuitry configured to: acquire a first time-sequence of values of the first property and a second timesequence of values of the second property; provide, at a first point in time following acquisition of a value of the first property indicating a sweat gland activity of the user that is higher than a predefined threshold activity, a first control signal to the heat-controlling arrangement encoding an instruction to increase heat flux from the user’s body; and provide, at a second point in time following acquisition of a value of the second property fulfilling a predefined requirement, a second control signal to the heat-controlling arrangement encoding an instruction to reduce heat flux from the user’s body.

Description

HOT FLASH MITIGATION Technical Field of the lnvention The present invention relates to a therapeutic system for mitigatingsymptoms of hot flashes experienced by a user, and to control circuitry forcontrolling operation of such a therapeutic system.

Technical Backgroundlt is well known that many users have problem with discomfort, caused by excessive sweating, and heat-sensation during their normal life.

There are many users affected by excessive sweating, known asHyperhidrosis. This involves, diabetes, over-weight, anxiety, cancer,hyperthyroidism and endometriosis.

Another group is women during their menopause, who are affected bythe discomforting symptoms of overvvhelming heat and excessive sweatingknown as hot-flashes. The generally accepted theory for hot-flashes is thatwhen the core body temperature reaches a trigger-point, the amygdalaactivates the sweat-glands, increases heart rate and initiates vasodilation.This process of increased sweating, vasodilation and increased heartrate,causes discomfort, initially intense heat, followed by excessive sweating andfinally excessive cooling, resulting in a discomfort to the user experiencingthis process. During the menopause, women have a decrease of femalehormones that appears to lower the thresholds between cold/neutral/hot andresult in difficulty to maintain a neutral state. Some users may experiencesuch discomfort, that they have to get up in the middle of the night and take ashower and even change bed-sheets. Another discomfort is nerve-pain.When being exposed to the excessive sweating during the hot-flash, itcreates a strong cooling-effect that creates a nerve-pain when the skin-temperature drops. The time-period of a hot-flash varies between 2-30minutes. Women who are breast-cancer survivors are known to have highfrequency of symptoms, and also increased severity of the symptoms, if theyare taking certain kinds of medication. Research also indicates that over-weight has an effect on the severity of hot-flashes. 2One way to reduce the symptoms is to exercise, but this requires diligence, and may have only little to no effect on certain users.

Another way is to take hormone medication, but that may have severeside-effects, especially if you are cancer-survivor.

There also exists a procedure, with an injection into the stellateganglion nerve group in the neck that reduces the menopause hot-flashes.However, this procedure is not without risks, as it includes risk such aspneumothorax (collapsed lung), seizures, spinal or epidural lock, allergy tomedication and nerve damage.

There have also been some examples of treating hot-flashes withelectric acupuncture but there are no certain effects and some women are notexperiencing any effects at all. For those who experience an improvement it isgradually disappearing from the moment when the treatment stops and formost women it will be lost within 6 months to a year. More research is neededto clarify the effective mechanisms of acupuncture for menopause.

Systems and method for mitigating the effects of hot flashes have beendescribed. US 2020/0013511 relates to a system including sensor circuitryand logic circuitry. According to US 2020/0013511, the sensor circuitryobtains a physical measurement associated with a user, the logic circuitrygenerates a predictive model that indicates a probability of the user having ahot flash at a date and time based on a plurality of input parameters, andrevises the probability based on the physical measurement using thepredictive model, and communicates data indicative of an action in responseto the revised probability being outside a threshold, such as providing coolingrelief. According to US 2020/0013511, the cooling may be stopped based onthe predictive model and/or additional measurements by the sensor circuitry.

US 2019/0008675 relates to a system and method for detecting theonset and conclusion of a hot flash. The system is configured to automaticallyoperate a cooling device to minimize the discomfort and effects of the hotflash on a user. The system includes a wearable device and a power controldevice. The wearable device measures conductance across the skin to detecthot flashes. When detected, the wearable device communicates with the 3power control device to activate a cooling device. The cooling device is deactivated when conductance readings detect the ending of the hot flash.

However, there still appears to be room for improvement. ln particular,it would be desirable to provide for more precision in the deactivation of thecooling.

Summarv of the lnvention ln view of the above-mentioned and other drawbacks of the prior art, ageneral object of the present invention is to provide for improved mitigation ofsymptoms of hot flashes, in particular to provide for more precision in thedeactivation of the cooling.

According to a first aspect of the present invention, these and otherobjects are achieved through control circuitry for controlling operation of atherapeutic system for mitigating symptoms of hot flashes experienced by auser, the therapeutic system comprising a sensing arrangement configured tosense a first property indicative of sweat gland activity of the user and asecond property indicative of a body temperature of the user, and a heat-controlling arrangement for controlling heat flux from the user's body, whereinthe control circuitry is configured to: acquire, from the sensing arrangement, afirst time-sequence of values of the first property and a second time-sequenceof values of the second property; provide, at a first point in time followingacquisition of a value of the first property indicating a sweat gland activity ofthe user that is higher than a predefined threshold activity, a first controlsignal to the heat-controlling arrangement encoding an instruction to increaseheat flux from the user's body; and provide, at a second point in time followingacquisition of a value of the second property fulfilling a predefinedrequirement, a second control signal to the heat-controlling arrangementencoding an instruction to reduce heat flux from the user's body.

The control circuitry according to embodiments of the present inventionmay advantageously be included in a therapeutic system for mitigatingsymptoms of hot flashes experienced by a user, further comprising a sensingarrangement configured to sense a first property indicative of sweat gland activity of the user, and a second property indicative of a body temperature of 4the user; and a heat-controlling arrangement for controlling heat flux from the user's body, wherein the sensing arrangement and the heat-controllingarrangement are coupled to the control circuitry.

According to a second aspect of the present invention, the above andother objects are achieved through a computer program comprisinginstructions which, when the program is executed by the control circuitryaccording to embodiments of the first aspect of the invention, cause thecontrol circuitry to: acquire, from the sensing arrangement, a first time-sequence of values of the first property and a second time-sequence ofvalues of the second property; provide, at a first point in time followingacquisition of a value of the first property indicating a sweat gland activity ofthe user that is higher than a predefined threshold activity, a first controlsignal to the heat-controlling arrangement encoding an instruction to increaseheat flux from the user's body; and provide, at a second point in time followingacquisition of a value of the second property fulfilling a predefinedrequirement, a second control signal to the heat-controlling arrangementencoding an instruction to reduce heat flux from the user's body.

The present invention is based upon the realization that increasedprecision in the determination a hot flash event can be achieved bydetermining a start of the hot flash event based on sweat gland activity, anddetermining an end of the hot flash event based on body temperature. lnparticular, the present inventor has found that this approach may provide forincreased precision in the determination of the end of the hot flash event,which allows timely cessation of heat-control (typically cooling). This may, inturn, reduce the level of discomfort felt by the user. lf the cooling ends toosoon, the user may feel intense heat, and if the cooling ends too late, the usermay freeze.

Moreover, it has been found to be advantageous to determine the endof the hot flash event, or rather to determine the time to stop cooling, basedon a relation between the current body temperature and a reference bodytemperature from the start of the hot flash event. Hereby, a kind of baselinecan be established, that may differ depending on the user and/or the circumstances. Typically, the reference body temperature may be different for 5different users, and may also differ depending on various factors, such as ambient temperature, humidity, weather, physical activity, time of day, etc.ln summary, the present invention thus relates to a therapeutic system comprising a sensing arrangement configured to sense a first propertyindicative of sweat gland activity, and a second property indicative of a bodytemperature; a heat-controlling arrangement for controlling heat flux from thebody; and control circuitry configured to: acquire a first time-sequence ofvalues of the first property and a second time-sequence of values of thesecond property; provide, at a first point in time following acquisition of avalue of the first property indicating a sweat gland activity of the user that ishigher than a predefined threshold activity, a first control signal to the heat-controlling arrangement encoding an instruction to increase heat flux from theuser's body; and provide, at a second point in time following acquisition of avalue of the second property fulfilling a predefined requirement, a secondcontrol signal to the heat-controlling arrangement encoding an instruction toreduce heat flux from the user's body.

Brief Description of the Drawinqs These and other aspects of the present invention will now be describedin more detail, with reference to the appended drawings showing a currentlypreferred embodiment of the invention, wherein: Fig 1 schematically shows an overview of an example embodiment ofthe system according to the present invention; Fig 2 is a representative illustration of values of body temperature andrelative humidity during a hot flash event without hot flash mitigation; Fig 3 is a representative illustration of values of body temperature andrelative humidity during a hot flash event when the system in fig 1 is inoperation; and Figs 4A-B schematically illustrate another example embodiment of thesystem according to the present invention. 6Detailed Description of an Example Embodiment of the lnvention Fig 1 schematically shows an example embodiment of the therapeuticsystem 1 according to the present invention in use during a hot flash event.Referring to fig 1, the therapeutic system 1 comprises a sensingarrangement 3, a heat-controlling arrangement 5, and a controller 7 forcontrolling operation of the therapeutic system 1.

The sensing arrangement 3 is configured to sense a first propertyindicative of a sweat gland activity of the user 9 and a second propertyindicative of a body temperature of the user 9. ln the example configuration ofthe therapeutic system 1 in fig 1, the sensing arrangement 3 is shown asbeing attached to or near the sternum of a user 9. As is schematically shownin the functional block diagram of the sensing arrangement 3 in fig 1, anexample configuration of the sensing arrangement 3 may comprise a firstsensor 11, a second sensor 13, an energy source 15, a communicationinterface 17, and a sensor arrangement control unit 19. The sensingarrangement 3 may also be placed on other parts of the body, such as theforearm, and may be contained in a wristlet, or be integrated into a smart-watch, that is able to sense the first property and the second property.

The first sensor 11 is configured to sense the above-mentioned firstproperty indicative of the sweat gland activity of the user 9, and may, forexample, be provided in the form of a humidity sensor, which measures therelative humidity near the body of the user. This is an indirect way to measurethe sweat gland activity. When the user starts to sweat, the humidity willincrease, as the sweat starts to evaporate. ln other configurations, the firstsensor 11 may be configured to sense the Electrodermal Activity (EDA).There are several ways this can be done. One, per se well known, method isto use Skin Conductance Response (SCR), which is proportional to theamount of sweat on the surface of the skin, where two electrodes areattached to the skin, and the current or voltage response to a stimulus signalis sensed. Another, per se well known, method is to use Sympathetic SkinResponse (SSR), which measures change of the electrical potential of theskin. The measured skin potential comes from the activated eccrine sweat gland. This is done by applying two spaced-apart conductive sensor pads to 7the skin, and measure the skin potential, preferably using an Analog to Digital converter using a high resolution and a high gain.

The second sensor 13 is configured to sense the above-mentionedsecond property indicative of the body temperature of the user 9, and may, forexample, be provided in the form of a skin temperature sensor.

The energy source 15 may, for example, be a suitable battery, and thecommunication interface 17 may be a wired interface, or a suitable wirelessinterface.

The sensor arrangement control unit 19 is powered by the energysource 15, and is coupled to the first 11 and second 13 sensors to acquiresensed values from the first 11 and second 13 sensors. The sensed valuesmay be stored in local memory, which may be included in the control unit 19,and can be provided externally via the communication interface 17.Additionally, the sensor arrangement may advantageously be provided with auser operable actuator, such as a button 20, by which the user 9 may beallowed to remotely operate the heat controlling arrangement 5. This may bebeneficial, for example, in case the user 9 experiences a hot flash thatdeviates from the anticipated course. One important benefit of this is that, inan embodiment with machine learning, this gives the machine learningalgorithm valuable training data. ln fig 1, the sensor arrangement is schematically shown as beingattached to the sternum of the user 9, but other attachment points arepossible, such as the forearm. This may be achieved in many different ways.One option is to have a clip and attach to the bra. Another method is to use asternum bra, wherein the sensor is clamped to the chest using a snug fit. ltcould also be pocket using a suitable fabric, such as a mesh, allowing heatand humidity to easily move from the body to the sensor system. I can also bethat the user applies the sensor using a sticker-type attachment, which allowsthe device to stay attached for a certain period of time. Another way would beto integrate the sensor arrangement 3 in a garment or in a blanket or quilt. ltcan also that the sensor arrangement is integrated into a smart-watch or a wristlet, and placed on the forearm of the user. 8The heat controlling arrangement 5 is configured to control heat flux from the user's 9 body. ln the example configuration of the therapeuticsystem 1 in fig 1, the heat controlling arrangement 5 is shown as beingremote from the user 9. As is schematically shown in the functional blockdiagram of the heat controlling arrangement 5 in fig 1, an exampleconfiguration of the heat controlling arrangement 5 may comprise a coolingactuator 21, an optional energy source 23, a communication interface 25, anda heat controlling arrangement control unit 27. The cooling arrangement 5may be powered by the grid or by a battery depending on the application. Thecooling actuator 21 may advantageously be an electric fan for cooling thebody of the user 9 with air-flow 29, to relieve the user 9 of the discomfort ofintense heat produced by the hot-flash and also excessive sweating. Thecooling process on the body is through convection and as a normal result of ahot flash the body also generates sweat, the air-flow 29 helps evaporate thesweat, which greatly helps cool of the body when having a hot flash.

The heat controlling arrangement control unit 27 is powered by theenergy source 23, and is coupled to the cooling actuator 21 and to thecommunication interface 25, to control operation of the cooling actuator 21based on control signals received via the communication interface 25, whichmay be a wired interface, or a suitable wireless interface.

The controller 7, which controls operation of the therapeutic system 1,comprises control circuitry, here in the form of a master control unit 31, asensor communication interface 33, a heat controlling communicationinterface 35, a memory 37, a user interface 39, which may include a displayand/or buttons etc. and, optionally, an energy source 41, and ambientsensors 43.

As will be described in greater detail further below, the master controlunit 31 acquires sensed values from the sensor arrangement 3, evaluates thesensed values to detect the onset and cessation of a hot flash event, andprovides control signals to the heat controlling arrangement 5 based on theevaluation, to increase heat flux from the user's 9 body during the hot flash event. 9ln embodiments where it is included in the user interface 39, the display may be useful for informing the user 9 of status, such as the currentoperating mode of the therapeutic system 1, settings of the therapeuticsystem 1, etc.

The optional ambient sensors 43 may include a room temperaturesensor and a room humidity sensor, and sensed values from these sensorsmay be used to calculate a heat index such as a Discomfort lndex or a Thomlndex (Thom 1959; Giles 1990). Such an index or similar can be used tobetter control the precision of the cooling delivered to the user 9. lt could beenvisaged that room temperature and humidity are measured and heat indexare calculated periodically, allowing the system to adjust over time,alternatively, that the system starts up with a certain periodicity.

Operation of the therapeutic system 1 will now be described withadditional reference to the schematic illustrations in fig 2 and fig 3 Fig 2 is a representative illustration of values of body temperature andrelative humidity during a hot flash event without hot flash mitigation. ln fig 2,the skin temperature T is represented by the solid line 45, and the relativehumidity RH close to the skin is represented by the dashed line 47. As wasmentioned further above, the relative humidity RH is a property indicative ofthe sweat gland activity of the user 9, and the skin temperature T is a propertyindicative of the body temperature of the user 9.

Referring to fig 2, the onset of the hot flash is at a first time ti. Theonset of the hot flash event is characterized by a marked increase in therelative humidity RH. At this point, the user 9 may typically not even be awarethat a hot flash is about occur.

At the second time tg, which may be approximately one minute afterthe first time t1, the user 9 typically starts to feel that the hot flash is coming,based on a feeling of slight heat and sweating.

At the third time tg, the user 9 would start to experience intense heatand sweating. The heat is the result of vasodilation that also triggers anincrease in skin temperature. At this point, the user 9 may instinctively start tocool off by loosening clothes or similar.

At the fourth time t4, the user 9 may start to feel sweating also in the back of the body, adding to the discomfort. The temperature increase is aresult of the vasodilation, where the skin starts to act as a heat-exchanger,circulating warm blood coming from within the core of the body.

At the fifth time t5, the user 9 starts to freeze.

Fig 3 is a representative illustration of values of body temperature andrelative humidity during a hot flash event when the system in fig 1 is inoperation.

Referring again to fig 1, the control circuitry (the master controller 31 infig 1) is configured to acquire, from the from the sensing arrangement 3, afirst time-sequence of values of a first property indicative of sweat glandactivity of the user 9 and a second time-sequence of values of a secondproperty indicative of the body temperature of the user 9. ln the exampleillustration in fig 3, the first property is relative humidity RH in the vicinity ofthe skin of the user 9, and the second property is the skin temperature T ofthe user 9.

The control circuitry continuously evaluates the acquired values of thefirst property (here, the relative humidity RH), and assesses the sweat glandactivity of the user 9 in relation to a threshold sweat gland activity. lnimplementations where the sensed property indicative of sweat gland activityis the relative humidity RH in the vicinity of the skin of the user 9, the rate ofchange of the relative humidity as a function of time may be taken torepresent sweat gland activity, and when the rate of change (derivative) ofRH(t) is higher than a threshold rate of change, it is concluded that it is likelythat a hot flash event is about to occur. ln fig 3, this time is indicated by tsiari(substantially corresponding to the first time t1 in fig 2). At this time, or at leastclose to this time, such as within five seconds of the start time tsiafi, anacquired value of the second property (skin temperature T) may bedesignated as a reference value Tref of the second property. The referencevalue Tfef of the second property may be the result of a combination of severalreadings, such as an average of several sensed values.

Directly upon the indication that the sweat gland activity of the user 9 exceeds the threshold (such as within a few seconds of this indication, for 11example within 5 seconds or within 3 seconds), the control circuitry provides a first control signal to the heat-controlling arrangement 5, encoding aninstruction to increase heat flux from the user's 9 body.

With continued reference to fig 1, the first control signal is received bythe heat controlling arrangement 5, through the communication interface 25,and the heat controlling arrangement control unit 27 decodes the instructionand controls the cooling actuator 21 to operate. ln embodiments, theinstruction may simply be an "ON" instruction, and in other embodiments, theinstruction may contain information about a desired cooling intensity orintensity profile.

Thanks to the cooling action, in this case air flow 29, provided by theheat controlling arrangement 5, the sweat on the body of the user 9evaporates faster than in the reference case illustrated by fig 2, and thetemperature increases less. As a consequence, the discomfort felt by theuser 9 can be greatly reduced.

During the hot flash event, the control circuitry continues to acquire andevaluate the acquired values of the first (RH) and second (T) properties. lnembodiments, the control circuitry may provide further control signals to theheat controlling arrangement 5, encoding instructions to modify the operationof the cooling actuator. ln other embodiments, no further action may be takenuntil the estimated end of the hot flash event is detected.

According to embodiments of the invention, the end of the hot flashevent is estimated to occur when an evaluation of the sensed values of thesecond property (T) indicates that a predefined requirement is fulfilled. Thispredefined requirement may relate to the rate of change of the bodytemperature of the user 9 - if the body temperature falls at a rate higher thana threshold rate, it may be concluded that the hot flash event is about to end.Advantageously, however, fulfilling the predefined requirement may includeexhibiting a predefined relation with respect to the above-mentionedreference temperature Tfef. ln embodiments, this predefined relation may be that the value of thesecond property indicates a body temperature that is lower than the body temperature indicated by the reference value of the second property plus a 12predetermined temperature offset. Experiments have shown that a temperature offset in the range of -0.5°C - 0°C may be suitable, but it isexpected that different users 9 may have somewhat different optimaltemperature offsets. ln other embodiments, the predefined relation may be that the value ofthe second property indicates a body temperature that is lower than a productof a predetermined factor and the body temperature indicated by thereference value of the second property. For instance, an indication that thebody temperature has fallen to T= K x Tfef, where K may, for example be inthe interval 0.95 < K < 1.0, may be considered to have fulfilled the above-mentioned predefined requirement. lt should, again, be noted that the actualrequirement may be individual to the particular user 9, and/or depend on, forexample, the ambient temperature and/or humidity. lt may be required thatthe value of the second property indicates a sufficiently low body temperatureseveral times in succession, and/or that a rolling average reading indicatesthe sufficiently low body temperature. ln embodiments, the control circuitrymay control the heat-controlling arrangement to intermittently stop the heatflux control, for example by stopping or significantly reducing intensity of thecooling provided by the cooling actuator 21. This may reduce the cooling ofthe sensing arrangement by the heat-controlling arrangement, to reduce therisk of acquiring values of the second property indicating a body temperaturethat is lower than it actually is. Furthermore, the acquisition of at least valuesof the second property may continue also after acquisition of one or severalvalue(s) of the second property fulfilling the predefined requirement. lf suchcontinued acquisition should indicate a rising body temperature, the controlcircuitry may provide a further control signal to the heat-controllingarrangement encoding an instruction to again increase the heat flux from theuser's 9 body.

Directly upon the indication, at the time denoted tand in fig 3, that thehot flash event is about to end or has ended (such as within a few seconds ofthis indication, for example within 5 seconds or within 3 seconds), the controlcircuitry provides a second control signal to the heat-controlling 13arrangement 5, encoding an instruction to reduce heat flux from the user's 9 body.

With continued reference to fig 1, the second control signal is receivedby the heat contro||ing arrangement 5, through the communication interface25, and the heat contro||ing arrangement control unit 27 decodes theinstruction and controls the cooling actuator 21 to reduce or cease operation.ln embodiments, the instruction may simply be an "OFF" instruction, and inother embodiments, the instruction may contain information about a desiredcooling intensity or intensity profile.

By reducing the cooling at or soon after the time tand where it isestimated that the hot flash event has ended or is about to end, excessivecooling can be prevented, so that the user does not freeze. ln the example configuration of the therapeutic system 1 in fig 1, thesensor arrangement 3, the heat contro||ing arrangement 5, and thecontroller 7 are illustrated as separate units communicating via respectivecommunication interfaces. lt should be understood that many otherconfigurations are possible and within the scope of the claims. For instance,the sensor arrangement 3 and the controller 7 may be provided in the sameunit, or the heat contro||ing arrangement 5 and the controller may be providedin the same unit. Furthermore, the controller 7 may be a dedicated device, orthe controller 7 may be embodied by a general purpose device programmedto carry out the functionality of the controller 7. As a particular example, thecontroller may be embodied by a mobile phone running an app.

Figs 4A-B schematically show a configuration of the therapeuticsystem 1 in which all parts of the system 1 are integrated together. ln fig 4A,the user 9 is shown in a front-facing outline, and in fig 4B in a back-facingoutline. Here, the system 1 is integrated in a wearable collar 49, wherein thecollar 49 integrates the sensor arrangement 3, the heat contro||ingarrangement 5, and the controller 7. One important aspect in suchembodiment is that it is possible to separate the collar 49 from the electronicsin order to be able to wash the collar.

The collar 49, is placed on top of the shoulders of the user 9, wherein the collar has a center portion on the back side shown in fig 4B, where a fan 1421a is located and a front side of the collar 49 shown in fig 4A, where two sleeves, one on each side of the neck, each contains a fan 21 b and 21c. Atleast one fan is needed, the remaining fans may be omitted, depending on the user's need. Another option is that all fans are mounted, but configuredindividually how much cooling effect they should generate.

When the fans 21 a-c are active, they are generating air flows 29a-ctowards the user.

The person skilled in the art realizes that the present invention by nomeans is limited to the preferred embodiments described above, and thatthere are many variations that fall within the scope of the claims. ln the claims, the word "comprising" does not exclude other elementsor steps, and the indefinite article "a" or "an" does not exclude a plurality. Asingle processor or other unit may fulfill the functions of several items recitedin the claims. The mere fact that certain measures are recited in mutuallydifferent dependent claims does not indicate that a combination of thesemeasured cannot be used to advantage. Any reference signs in the claimsshould not be construed as limiting the scope.

Claims

1. Control circuitry for controlling operation of a therapeutic system formitigating symptoms of hot flashes experienced by a user, the therapeuticsystem comprising a sensing arrangement configured to sense a first propertyindicative of sweat gland activity of the user and a second property indicativeof a body temperature of the user, and a heat-controlling arrangement forcontrolling heat flux from the user's body, wherein the control circuitry isconfigured to: acquire, from the sensing arrangement, a first time-sequence of valuesof the first property and a second time-sequence of values of the secondproperty; provide, at a first point in time following acquisition of a value of the firstproperty indicating a sweat gland activity of the user that is higher than apredefined threshold activity, a first control signal to the heat-controllingarrangement encoding an instruction to increase heat flux from the user'sbody;and provide, at a second point in time, later than the first point in time,following acquisition of a value of the second property fulfilling a predefinedrequirement, a second control signal to the heat-controlling arrangement encoding an instruction to reduce heat flux from the user's body.

2. Control circuitry according to claim 1, wherein fulfilling thepredefined requirement includes exhibiting a predefined relation with respectto a reference value of the second property acquired in connection with thefirst point in time.

3. Control circuitry according to claim 2, wherein the predefined relationis that the value of the second property indicates a body temperature that islower than the body temperature indicated by the reference value of thesecond property plus a predetermined temperature offset.

4. 164. Control circuitry according to claim 3, wherein the predetermined temperature offset is negative.

5. Control circuitry according to claim 2, wherein the predefined relationis that the value of the second property indicates a body temperature that islower than a product of a predetermined factor and the body temperatureindicated by the reference value of the second property.

6. Control circuitry according to any one of the preceding claims,wherein: the control circuitry is further configured to acquire a third time-sequence of values of a third property indicative of an ambient condition; and the predefined requirement is dependent on the ambient condition.

7. A therapeutic system for mitigating symptoms of hot flashesexperienced by a user, comprising: a sensing arrangement configured to sense a first property indicative ofsweat gland activity of the user, and a second property indicative of a bodytemperature of the user; a heat-controlling arrangement for controlling heat flux from the user'sbody;and the control circuitry according to any one of the preceding claimscoupled to the sensing arrangement and to the heat-controlling arrangement.

8. The therapeutic system according to claim 7, wherein the sensingarrangement comprises:a first sensor for sensing the first property; anda second sensor for sensing the second property.

9. The therapeutic system according to claim 8, wherein the secondsensor is configured to sense a humidity or an electrical property of the skinof the user.

10. 1710. The therapeutic system according to any one of claims 7 to 9, wherein the sensing arrangement is further configured to sense a thirdproperty indicative of an ambient condition.

11. The therapeutic system according to claim 10, wherein the ambientcondition includes at least one of an ambient temperature and an ambienthumidity.

12. The therapeutic system according to any one of claims 7 to 11, wherein the heat-contro||ing arrangement comprises a fan.

13. A computer program comprising instructions which, when theprogram is executed by the control circuitry according to claim 1, cause thecontrol circuitry to: acquire, from the sensing arrangement, a first time-sequence of valuesof the first property and a second time-sequence of values of the secondproperty; provide, at a first point in time following acquisition of a value of the firstproperty indicating a sweat gland activity of the user that is higher than apredefined threshold activity, a first control signal to the heat-contro||ingarrangement encoding an instruction to increase heat ﬂux from the user'sbody;and provide, at a second point in time following acquisition of a value of thesecond property fulfilling a predefined requirement, a second control signal tothe heat-contro||ing arrangement encoding an instruction to reduce heat fluxfrom the user's body.