COMMUNICATION HEADSET WITH A STRESS MANAGEMENT FUNCTION

Abstract

Disclosed is a method, a headset and a system for determining heart rate data of a user. The system comprising a headset for voice communication, the headset being configured to be worn at least partly at or in the ear of the user, the headset comprising: a voice communication unit for enabling a voice communication call mode for establishing a call between the headset and a far-end device; a speaker for reproduction of audio signals; a microphone for reception of audio signals; a photoplethysmograph (PPG) sensor for optically measuring through the skin of the user in or at the ear of the user; wherein the system comprises a processing unit connected to the PPG sensor, where the processing unit is configured for determining heart rate data of the user based on the PPG sensor measurements; wherein the system comprises detecting whether the user is on-call with a far-end device or off-call; and wherein the system comprises a data communication unit for providing the determined heart rate data of the user, when the user is wearing the headset, for indication of the heart rate data of the user.

Claims

1-15. (canceled)

16. A system for determining heart rate data of a user and thus whether a user is in an on-call or off-call state with a far-end device, the system comprising; a headset for voice communication, the headset being configured to be worn at least partly at or in the ear of the user, the headset comprising: a headset enabling a voice communication call mode for establishing a call between the headset and a far-end device; a speaker for reproduction of audio signals; a microphone for reception of audio signals; a photoplethysmograph (PPG) sensor for optically measuring through the skin of the user in or at the ear of the user; wherein the system comprises a processor connected to the PPG sensor, where the processor is configured for determining heart rate data of the user based on the PPG sensor measurements; wherein the system comprises detecting whether the user is on-call with a far-end device or off-call; wherein the system comprises a data communicator for providing the determined heart rate data of the user, when the user is wearing the headset, for indication of the heart rate data of the user; a motion sensor located in said headset configured to monitor physical motion of the user to exclude heart rate data collected during periods of substantial physical activity, which may be falsely interpreted as work related stress; and wherein the system determines whether a user is on-call or off-call based on heart rate data of the user, where it is assumed that the user is calm and not stressed in an off-call state and that an on-call heart rate is higher than an off-call heart rate; and wherein heart rate data collected, excluding heart rate data during said physical activity, from the user is used to determine effects of workload on the user.

17. The system according to claim 16, wherein the processor is configured for determining the heart rate and determining beat-to-beat intervals based on the PPG sensor measurements, and wherein the processor is configured for determining a heart rate variability during a time interval based on the beat-to-beat interval, excluding heart rate data during said physical activity, and off-call periods are assumed to be non-stressed and compared to on-call periods for purposes of determining stress levels.

18. The system according to claim 16, wherein the processor is configured for determining low frequency components and high frequency components based on the heart rate variability, excluding heart rate date during said physical activity, where the low frequency components and the high frequency components are components in a beat-to beat periodogram, where the beat-to beat periodogram is based on the determined beat-to beat intervals.

19. The system according to claim 16, wherein the processor is configured for determining a baseline measurement of the low frequency components and the high frequency components during a first time interval T1, when the user is off-call, and wherein the processor is configured for measuring a first ratio between the low frequency components and the high frequency components during the first time interval T1.

20. The system according to claim 18, wherein the p processor is configured for measuring a second ratio (LF/HF-on call) between the low frequency components and the high frequency components during a second time interval T2, when the user is on-call.

21. The system according to claim 16, wherein the processor is configured to detect stress by detection of the heart rate exceeding a first predefined threshold value or by detection of the second ratio exceeding a second predefined threshold value.

22. The system according to claim 16, wherein the system comprises a detector providing a notification, if the processor detects a heart rate increase of the user, excluding heart rate date during said physical activity.

23. The system according to claim 16, wherein the headset-comprises a motion sensor configured for detecting head movements of the user for filtering out motion-induced artefacts in the PPG sensor measurements and substantial user physical activity.

24. The system according to claim 16, wherein the headset is configured such that the PPG sensor is arranged at the preauricular skin pit area of the user for obtaining the PPG signal from the superficial temporary artery, when the user is wearing the headset.

25. The system according to claim 16, wherein the headset is configured such that the PPG sensor is arranged at less than 5 mm over the skin surface, such as less than 4 mm, or such as less than 3 mm, or such as less than 2 mm, or such as less than 1 mm over the skin surface, when the user is wearing the headset.

26. The system according to claim 16, wherein the headset comprises an earphone housing, and wherein an ear cushion is mounted on the earphone housing, and wherein the PPG sensor is mounted in the earphone housing or in the ear cushion.

27. The system according to claim 16, wherein the earphone housing comprises a protrusion where the PPG sensor is configured to be arranged, such that the protrusion is configured to rest/be situated at the preauricular skin pit area of the user, when the user is wearing the headset.

28. The system according to claim 16, wherein the headset comprises a holder capable of fixing the position of the earphone housing, when the user is wearing the headset, such that the PPG sensor is arranged at the preauricular skin pit area of the user.

29. The system according to claim 16, wherein the system comprises an on-call indicator for indicating if the headset is in a call mode or in a non-call mode for detecting whether the user is on-call with a far-end device or off-call.

30. A system for determining heart rate data of a user, the system comprising a headset for voice communication, the headset being configured to be worn at least partly at or in the ear of the user, the headset comprising: a headset enabling a voice communication call mode for establishing a call between the headset and a far-end device; a speaker for reproduction of audio signals; a microphone for reception of audio signals; a photoplethysmograph (PPG) sensor for optically measuring through the skin of the user in or at the ear of the user; wherein the system comprises a processor connected to the PPG sensor, where the processor is configured for determining heart rate data of the user based on the PPG sensor measurements; a motion sensor located in said headset configured to monitor physical motion of the use and to exclude heart rate data collected during periods of substantial physical activity, which may be falsely interpreted as work related stress; wherein the system comprises detecting whether the user is on-call with a far-end device or off-call and wherein PPG sensor data during off-call period are assumed to be non-stressed and compared to on-call periods for purposes of determining stress levels excluding periods which have been detected where the user is performing substantial physical activity; wherein the system comprises a data communicator for providing the determined heart rate data of the user, when the user is wearing the headset, for indication of the heart rate data of the user.

31. A system for determining heart rate data of a user, the system comprising a headset for voice communication, the headset being configured to be worn at least partly at or in the ear of the user, the headset comprising: a headset enabling a voice communication call mode for establishing a call between the headset and a far-end device; a speaker for reproduction of audio signals; a microphone for reception of audio signals; a photoplethysmograph (PPG) sensor for optically measuring through the skin of the user in or at the ear of the user; a motion sensor located in said headset configured to monitor physical motion of the user to exclude heart rate data collected during periods of substantial physical activity, which may be falsely interpreted as work related stress; wherein the earphone housing comprises a protrusion where the PPG sensor is configured to be arranged, such that the protrusion is configured to rest/be situated at the preauricular skin pit area of the user, when the user is wearing the headset; wherein the headset includes a faceplate for holding the PPG sensor, where the faceplate includes angled protrusion which extends outwardly from the faceplate at an oblique angle relative to a centreline extending perpendicular out of the faceplate; wherein the system comprises processor connected to the PPG sensor, where the processor is configured for determining heart rate data of the user based on the PPG sensor measurements, excluding such periods when the user is performing substantial physical activity; wherein the system comprises detecting whether the user is on-call with a far-end device or off-call; and wherein the system comprises a data communicator for providing the determined heart rate data of the user, when the user is wearing the headset, for indication of the heart rate data of the user.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0098] The above and other features and advantages will become readily apparent to those skilled in the art by the following detailed description of exemplary embodiments thereof with reference to the attached drawings, in which:

[0099] FIG. 1 schematically illustrates an example of a system 2 for determining heart rate data of a user.

[0100] FIG. 2 schematically illustrates an example of a system 2 for determining heart rate data of a user.

[0101] FIG. 3 schematically illustrates a photoplethysmograph (PPG) sensor optically measuring through the skin of the user.

[0102] FIG. 4 schematically illustrates a method performed in a system for determining heart rate data of a user.

[0103] FIG. 5 schematically illustrates a method for a well-being analysis, such as detecting stress of a user, wearing a headset comprising a PPG sensor.

[0104] FIG. 6 schematically illustrates a method for a well-being analysis, such as detecting stress of a user, wearing a headset comprising a PPG sensor.

[0105] FIG. 7 schematically illustrates the anatomy of the outer ear showing the approximate position of the preauricular skin pit.

[0106] FIGS. 8A-8B schematically illustrate a headset with a PPG sensor and an earcup of the headset with a circumaural design.

[0107] FIG. 9A schematically illustrates an angled earphone housing, comprising a protrusion, provided in the earcups of the headset.

[0108] FIG. 9B illustrates with the dotted line the optimal position for the protrusion or angled part of the earphone housing, see FIG. 9A.

DETAILED DESCRIPTION

[0109] Various embodiments are described hereinafter with reference to the figures. Like reference numerals refer to like elements throughout. Like elements will, thus, not be described in detail with respect to the description of each figure. It should also be noted that the figures are only intended to facilitate the description of the embodiments. They are not intended as an exhaustive description of the claimed invention or as a limitation on the scope of the claimed invention. In addition, an illustrated embodiment needs not have all the aspects or advantages shown. An aspect or an advantage described in conjunction with a particular embodiment is not necessarily limited to that embodiment and can be practiced in any other embodiments even if not so illustrated, or if not so explicitly described.

[0110] Throughout, the same reference numerals are used for identical or corresponding parts.

[0111] FIG. 1 schematically illustrates an example of a system 2 for determining heart rate data of a user. The system 2 comprises a headset 4 for voice communication. The headset 4 is configured to be worn at least partly at or in the ear of the user. The headset 2 comprises a voice communication unit 6 for enabling a voice communication call mode for establishing a call between the headset 4 and a far-end device (not shown). The headset 2 comprises a speaker 8 for reproduction of audio signals. The headset 2 comprises a microphone 10 for reception of audio signals. The headset 2 comprises a photoplethysmograph (PPG) sensor 12 for optically measuring through the skin of the user in or at the ear of the user.

[0112] The system 2 comprises a processing unit 14 connected to the PPG sensor 12, where the processing unit 14 is configured for determining heart rate data of the user based on the PPG sensor measurements. In FIG. 1 the processing unit 14 is shown in the headset 2. However the processing unit 14 may alternatively and/or additionally be arranged in an external device 18 external from the headset, e.g. in the user's computer, and/or in a computer belonging or being controlled by a supervisor/manager to the user.

[0113] The system 2 comprises detecting whether the user is on-call with a far-end device or off-call.

[0114] The system 2 comprises a data communication unit 16 for providing the determined heart rate data of the user, when the user is wearing the headset 4, for indication of the heart rate data of the user. In FIG. 1 the data communication unit 16 is shown to be provided in the headset 2. However if the processing unit 14 is arranged in the external device 18 external from the headset 2, the data communication unit 16 may also be arranged in the external device 18, such as in user's computer, in the supervisor/managers computer etc.

[0115] The communication 20 between the headset 2 and the external device 18 may be via a wired connection or via a wireless connection, such as Bluetooth. The external device 18 may comprise a data communication unit 22 for data communication with the data communication unit 16 in headset 2.

[0116] The external device 18 may further comprise a display 28 for displaying heart rate data of the user.

[0117] FIG. 2 schematically illustrates an example of a system 2 for determining heart rate data of a user. The system 2 comprises a headset 4 for voice communication. The headset 4 is configured to be worn at least partly at or in the ear of the user. The headset 2 comprises a voice communication unit 6 for enabling a voice communication call mode for establishing a call between the headset 4 and a far-end device (not shown). The headset 2 comprises a speaker 8 for reproduction of audio signals. The headset 2 comprises a microphone 10 for reception of audio signals. The headset 2 comprises a photoplethysmograph (PPG) sensor 12 for optically measuring through the skin of the user in or at the ear of the user.

[0118] The system 2 comprises a processing unit 14 connected to the PPG sensor 12, where the processing unit 14 is configured for determining heart rate data of the user based on the PPG sensor measurements. In FIG. 2 the processing unit 14 is shown in the headset 2. However the processing unit 14 may alternatively and/or additionally be arranged in an external device 18 external from the headset, e.g. in the user's computer, and/or in a computer belonging or being controlled by a supervisor/manager to the user.

[0119] The system 2 comprises detecting whether the user is on-call with a far-end device or off-call.

[0120] The system 2 comprises a data communication unit 16 for providing the determined heart rate data of the user, when the user is wearing the headset 4, for indication of the heart rate data of the user. In FIG. 1 the data communication unit 16 is shown to be provided in the headset 2. However if the processing unit 14 is arranged in the external device 18 external from the headset 2, the data communication unit 16 may also be arranged in the external device 18, such as in user's computer, in the supervisor/managers computer etc.

[0121] The communication 20 between the headset 2 and the external device 18 may be via a wired connection or via a wireless connection, such as Bluetooth. The external device 18 may comprise a data communication unit 22 for data communication with the data communication unit 16 in headset 2.

[0122] The external device 18 may further comprise a display 28 for displaying heart date data of the user.

[0123] FIG. 2 further shows that the headset may comprise a microphone boom 24 comprising the microphone 10. The headset may also comprise a headband 34 or neckband for attaching the headset 2 to the head of the user. The shown headset 2 in FIG. 2 is a headset with only one earcup and thus one speaker 8 to cover one ear. The headset 2 is configured to attach to the head of the user at the part 36. Alternatively, the headset 2 may comprise one earbud, or two earcups or two earbuds.

[0124] FIG. 3 schematically illustrates a photoplethysmograph (PPG) sensor optically measuring through the skin of the user.

[0125] The reflection PPG sensor is configured to be arranged in proximity to the skin or in contact with the skin of the user, e.g. by being attached to the body. The PPG sensor is configured to use an LED (light emitting diode) light source generating blue (465 nm) and/or green (520 nm) and/or infrared (940 nm) light and/or a combination of lights of multiple wavelengths. A photodetector in the PPG sensor is configured to measure the intensity of the reflected light from the skin/tissue/blood of the user. Due to the absorption of light in blood the reflected light is inversely proportional to the blood volume in the line of sight and can thus be used to track the pulsation of arterial blood.

[0126] FIG. 3 schematically illustrates that the light source transmits and reflects through tissues, venous blood, the non-pulsatile component of artery blood and the pulsatile component of artery blood, see top part of FIG. 3. The bottom part of FIG. 3 schematically illustrates that the intensity of the reflected light is configured to be measured by the photodetector in the PPG sensor during a time interval (x-axis is time). Due to the absorption of light in blood the reflected light is inversely proportional to the blood volume in the line of sight and can thus be used to track the pulsation of arterial blood.

[0127] FIG. 4 schematically illustrates a method 100 performed in a system 2 for determining heart rate data of a user. The method comprises the following steps:

[0128] In step 102 a heart rate (HR) of the user is determined.

[0129] In step 104 beat-to-beat (RRi) intervals of the user is determined.

[0130] In step 106 a heart rate variability (HRV) of the user is determined during a time interval, where the determination 106 is based on the determined beat-to-beat (RRi) intervals from step 104.

[0131] In step 108 low frequency (LF) components and high frequency (HF) components are determined based on the heart rate variability (HRV) from step 106, where the low frequency (LF) components and the high frequency (HF) components are components in a beat-to beat (RRi) periodogram, where the beat-to beat (RRi) periodogram is based on the determined beat-to beat (RRi) intervals from step 104.

[0132] In step 110 a baseline measurement of the low frequency (LF) components and the high frequency (HF) components is determined during a first time interval T1, when the user is off-call, and the processing unit is configured for measuring a first ratio (LF/HF-off call) between the low frequency (LF) components and the high frequency (HF) components during the first time interval T1.

[0133] In step 112 a second ratio (LF/HF-on call) between the low frequency (LF) components and the high frequency (HF) components is measured during a second time interval T2, when the user is on-call.

[0134] In step 114 stress is detected by detection of the heart rate exceeding a first predefined threshold value (threshold1) and/or by detection of the second ratio (LF/HF on-call) exceeding a second predefined threshold value (threshold2).

[0135] FIG. 5 schematically illustrates a method for a well-being analysis, such as detecting stress of a user, wearing a headset comprising a PPG sensor.

[0136] For detecting stress of the user and/or providing a well-being analysis, the following method may be performed.

[0137] Detecting and signaling stress during a call may be provided. In order to truly detect a stress period from non-stress period of the user a baseline measurement may be provided. The processor of the communication headset may know the call context, such as on call, not on call etc.

[0138] Thus the processor of the communication headset may be configured to know when the user is on-call. Therefore the processor may be configured to perform the baseline measurement when the user is not on call, and the processor may be configured to measure HRV during a non-call period and during a call. The processor of the communication headset may therefore be configured to detect a change in stress or anger situation and provide a feedback, e.g. intervention, to the user and/or manager and thus provide feedback influencing the user to relax such as to restrain himself or herself. The feedback to the user can be visual or by means of an audio signal provided to the user in the headphones.

[0139] In FIG. 5 the method comprises transmitting the PPG sensor input 502 to a heart rate (HR) signal extraction 504. The system or the headset detects 506 if the headset is on the user's head. If the headset is not, 508, on the user's head, return to PPG sensor input 502 and HR signal extraction 504. If the headset is on, 510, the user's head, continue to record heart rate (HR) for analyzing stress metrics 512. Then determine 514 if the user in on-call or off-call. If the user is not on-call, 516, then continue to well-being biometric logging (heart rate, stress metrics, on-call detector) 518. If the user is on-call, 520, then continue to determine 522 if stress index exceeds a threshold. If stress index does not exceed a threshold 524, continue to well-being biometric logging (heart rate, stress metrics, on-call detector) 518. If stress index does exceed a threshold 526, then generate on-the-spot stress feedback 528 to the user and continue to well-being biometric logging (heart rate, stress metrics, on-call detector) 518.

[0140] FIG. 6 schematically illustrates a method for a well-being analysis, such as detecting stress of a user, wearing a headset comprising a PPG sensor.

[0141] In FIG. 6 a number of thresholds are used:

[0142] t1—absolute LF/HF stress threshold.

[0143] t2—duration when LF/HF>t1 is considered a true stress situation.

[0144] TB1—stress threshold relative to a baseline situation, e.g. at the start of a work day.

[0145] TB2—duration when LF/HF>TB1 is considered a true on-the-spot stress situation.

[0146] There are different ways of implementing the signal analysis and data collection and intervention.

[0147] The headset can be USB wired or wireless. The signal processing, analysis and intervention may be performed in or through the headset. The resulting HR, HRV and stress metrics may be delivered via a Bluetooth connection or Bluetooth Low Energy connection to a Health app in a smartphone or on a tablet or PC. The resulting HR, HRV and stress metric may be delivered via USB to a connected PC or tablet. Alternatively and/or additionally, the signal processing analysis and intervention may be performed outside the headset, such as in an external processor and/or using an app in a smartphone or in a connected PC or tablet.

[0148] In FIG. 6 the method comprises starting 602 when the user is not in call 604, i.e. off-call. Here the baseline LF, HF components and their ratio are measured. Then it is determined 606 if the LF/HF is above the absolute threshold t1. If the LF/HF is not, 608, above the absolute threshold t1, then return to the state where the user is not in call 604, i.e. off-call, where the baseline LF, HF components and their ratio are measured. If the LF/HF is above the absolute threshold t1, 610, then continue to determine 612 if the time of (LF/HF above the absolute threshold) exceeds the t2 threshold. If the time of (LF/HF above the absolute threshold) does not, 614, exceed the t2 threshold, then log no stress, 616, and return to the state where the user is not in call 604, i.e. off-call, where the baseline LF, HF components and their ratio are measured. If the time of (LF/HF above the absolute threshold) exceeds, 618, the t2 threshold, then log stress 620, and return to the state where the user is not in call 604, i.e. off-call, where the baseline LF, HF components and their ratio are measured.

[0149] For the case where the user is in-call 622, the LF, HF components and their ratio are measured. The change between the user being not in call 604 and the user being in call 622 may be due to either a call is ended 624 or that a new call 626 has begun. When the user is in call 622, it is determined 628, if the LF/HF is above the baseline threshold TB1. If the LF/HF is not, 630, above the baseline threshold TB1, then return to the state where user is in-call 622, where the LF, HF components and their ratio are measured. If the LF/HF is, 632, above the baseline threshold TB1, then determine 634 if the time of (LF/HF above baseline threshold TB1) exceeds TB2 threshold. If the time of (LF/HF above baseline threshold TB1) does not, 636, exceed TB2 threshold, then return to the state where user is in-call 622, where the LF, HF components and their ratio are measured. If the time of (LF/HF above baseline threshold TB1) exceeds, 638, TB2 threshold, then generate on-call on-the-spot feedback 640, and then return to the state where user is in-call 622, where the LF, HF components and their ratio are measured.

[0150] FIG. 7 schematically illustrates the anatomy of the outer ear showing the approximate position of the preauricular skin pit 72. The PPG sensor in the headset is configured to be arranged at the preauricular skin pit area of the user for obtaining the PPG signal from the superficial temporary artery, when the user is wearing the headset.

[0151] FIGS. 8A-8B schematically illustrate a headset with a PPG sensor and an earcup of the headset with a circumaural design.

[0152] The mounting or provision of the PPG sensor 12 in the headset 4 may be provided by that the earcup 40 of the headset 4 is of a circumaural design, see FIG. 8A. The earcup 40 comprises an earphone housing 44 and an ear cushion material 42. In case of a circumaural design, the preauricular skin pit area of the user may be a suitable place to measure the PPG signal. FIG. 8B shows that the PPG sensor 12 may in such case be embedded in the ear cushion material 42, which is typically polyurethane or polyester foam. The ear cushion material 42 may be configured such that is it exposing the optical sensor in the PPG 12 such that the optical sensor can be in contact with or close to skin, such within 1-4 mm from the surface of the skin.

[0153] FIG. 9A schematically illustrates an angled, folded or bended earphone housing 44 provided in the earcups 40, see FIG. 8, of the headset. The angled, folded or bended earphone housing 44 may provide a proper location of the PPG sensor at the preauricular skin pit area of the user for obtaining the PPG signal from the superficial temporal artery of the user.

[0154] The earphone housing 44 comprise a protrusion 46 where the PPG sensor is configured to be arranged, such that the protrusion is configured to rest/be situated at the preauricular skin pit area of the user, when the user is wearing the headset. The protrusion 46 may be an angled part, a raised part, a bend etc. For example, the earphone housing 44 may comprise a first face 48 configured to point towards the ear/skin of the user when the user is wearing the headset. The earphone housing 44 may comprise a second face 50 configured to point towards the surroundings when user is wearing the headset. The protrusion 46 may be arranged in the first face 48. The protrusion 46 may be an angled part having an angle relative to a plane, e.g. the plane of the second face 50, of between 10 degrees and 60 degrees. The protrusion 46 or angled part may be arranged at a centreline of the earphone housing 44, or arranged skew/oblique relative to a centreline of the earphone housing 44.

[0155] FIG. 9B illustrates with the dotted line the optimal position for the protrusion or angled part of the earphone housing, see FIG. 9A.

[0156] Although particular features have been shown and described, it will be understood that they are not intended to limit the claimed invention, and it will be made obvious to those skilled in the art that various changes and modifications may be made without departing from the scope of the claimed invention. The specification and drawings are, accordingly to be regarded in an illustrative rather than restrictive sense. The claimed invention is intended to cover all alternatives, modifications and equivalents.

LIST OF REFERENCES

[0157] 2 system

[0158] 4 headset

[0159] 6 voice communication unit of headset

[0160] 8 speaker of headset

[0161] 10 microphone of headset

[0162] 12 photoplethysmograph (PPG) sensor

[0163] 14 processing unit

[0164] 16 data communication unit

[0165] 18 external device

[0166] 20 communication between headset and external device

[0167] 22 data communication unit of external device

[0168] 24 microphone boom of headset

[0169] 28 display of external device

[0170] 34 headband of headset

[0171] 36 head fixation part of headset

[0172] 40 earcup

[0173] 42 ear cushion

[0174] 44 earphone housing

[0175] 46 protrusion in earphone housing for PPG sensor

[0176] 48 first face of earphone housing

[0177] 50 second face of earphone housing

[0178] 72 preauricular skin pit

[0179] 100 method for determining heart rate data of a user

[0180] 102 method step of determining a heart rate (HR);

[0181] 104 method step of determining beat-to-beat (RRi) intervals;

[0182] 106 method step of determining a heart rate variability (HRV) during a time interval based on the determined beat-to-beat (RRi) intervals;

[0183] 108 method step of determining low frequency (LF) components and high frequency (HF) components based on the heart rate variability (HRV);

[0184] 110 method step of determining a baseline measurement of the low frequency (LF) components and the high frequency (HF) components during a first time interval T1, when the user is off-call;

[0185] 112 method step of measuring a second ratio (LF/HF-on call) between the low frequency (LF) components and the high frequency (HF) components during a second time interval T2, when the user is on-call;

[0186] 114 method step of detecting stress

[0187] 502-528 method steps of method for a well-being analysis, such as detecting stress of a user, wearing a headset comprising a PPG sensor

[0188] 602-640 method steps of a method for a well-being analysis, such as detecting stress of a user, wearing a headset comprising a PPG sensor