Stress-reducing lighting

Abstract

Devices, systems, and methods are provided for reducing stress and / or other beneficial human health effects by controlling one or more properties of lighting observed by humans, such as color (or wavelength) and / or intensity. Area lighting (e.g., for rooms, vehicles) and / or specific installations (e.g., medical installations) include the devices or systems provided herein. In operation, a lighting fixture or other light source outputs light in a selected region of the visible light spectrum, e.g., the amber region (e.g., 570 nm to 680 nm), the red region (e.g., above 680 nm), and the green region (e.g., 510 nm to 540 nm), but not including other regions (e.g., below 510 nm). The light emitted by the system or device can account for some, most, or all of the emitted flux received by humans, and stress-reduction benefits can be demonstrated through biological or biometric testing.

Description

[Technical Field]

[0001] The present disclosure relates to the fields of electronics and lighting. More specifically, methods, devices, and systems are provided for emitting light in a manner (e.g., with respect to wavelength, color spectrum, etc.) designed to reduce stress and / or maintain a relatively stress-free state for humans. [Background technology]

[0002] Medical and dental patients, students, commuters, office workers, and other people are exposed to varying degrees of stress due to health conditions, school obligations, traffic conditions, job demands, etc. Many environments in which people experience stress are illuminated to enhance safety or to provide illumination for reading or physical work, but lighting can exacerbate a person's stress. For example, bright lighting can aid in the performance of physical tasks, but excessive brightness can also cause dazzling and visual discomfort.

[0003] Background and area lighting have been used to support visual function almost exclusively using light wavelengths in the 300 nm to 700 nm range. Visual function refers to the performance of components of the human visual system, including spectral (color) and contrast discrimination, and contrast sensitivity (the ability to perceive contrast). Spectral enhancements and increased intensity levels within the typical visible spectrum can be used to support visual function, primarily for visual performance issues.

[0004] While some professional environments have been designed to enhance comfort by implementing soothing interior design, wall / floor / ceiling colors, comfortable furniture, glare-free lighting, and / or dimmable lighting, traditionally, lighting color or spectrum has not been intelligently adjusted to provide additional benefits, such as stress reduction. Summary of the Invention [Means for solving the problem]

[0005] In some embodiments, methods and devices are provided for emitting light in one or more color ranges that have been found to significantly reduce or alleviate stress in humans and maintain a relatively stress-free state. More specifically, the light spectrum implemented in these embodiments can reduce stress markers and cortisol in humans exposed to the illumination and can also help generate positive brainwave patterns. These embodiments can be particularly useful and effective in medical and / or dental environments where patients may be undergoing procedures or stressful tests (e.g., using MRI or magnetic resonance imaging machines) or recovering from such procedures or tests. They can also be of great help in other potentially stressful environments (e.g., while driving, working, studying).

[0006] In some embodiments, an area lighting system for a room or other space, or a system including one or more respective lighting devices, is configured to permanently or periodically generate light within one or more desired spectrums. For example, illumination in one color region can be provided for a first period of time, followed by illumination in a different color region for a second period of time, and so on.

[0007] Additionally, or alternatively, each lighting device or equipment can be configured to generate light as described herein. For example, medical devices or equipment (e.g., MRI, CT (Computed Tomography) scanners, blood transfusion equipment, pre- / post-operative holding rooms, etc.), lamps, spotlights, and / or other lighting hardware can be enhanced with the ability to provide light in one or more color regions. Similarly, a relatively small area within a larger space can be illuminated using a useful light spectrum, while some or all of the remaining portion of the larger space can be illuminated in some other manner.

[0008] Thus, in different embodiments, light produced in a particular color region can account for different proportions or percentages of the total emitted flux from some or all of the light sources illuminating a given space or area. For example, in a medical recovery room, lighting can be configured or adjusted so that 80% or more of the total flux is in the amber region (e.g., 570 nm to 680 nm). Other exemplary conditions or limitations can include: (a) less than 5% of the total flux in another region (e.g., 510 nm to 540 nm); (b) less than 10% of the total flux is in wavelengths greater than 680 nm; and / or (c) no luminous flux below 510 nm is included.

[0009] As another example, for an area lighting system for a room, 50% to 100% of the total radiant flux emitted by the area's lighting hardware may be centered around 590 nm (amber), plus or minus some margin (e.g., 50 nm). For smaller areas, such as when the lighting systems provided herein are incorporated into medical devices or equipment, the colored (e.g., non-white) light output may account for an even higher percentage (e.g., up to 100%) of the total radiant flux.

[0010] Embodiments can be implemented in private and / or public areas and can provide particular benefits in locations such as clinics and waiting rooms, operating rooms, recovery rooms, rest rooms for medical and professional staff, treatment areas for conditions such as post-traumatic stress disorder, psychiatric illnesses, bereavement, pediatric illnesses, etc. Additionally, devices that illuminate limited areas (e.g., lamps, overhead lights) can provide benefits to individuals engaged in stressful tasks. Thus, at least a portion of a student's study area, or the area he or she views while studying, can be illuminated by one or more lighting devices outputting the light spectrums described herein. Similarly, automobiles can emit interior lighting using the custom light spectrums described above in some or all areas that may be viewed by the driver and / or passengers. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 shows the recovery rate of stressed subjects during exposure to different light spectrums, according to some embodiments. [Figure 2] FIG. 2 is a flowchart illustrating a method for applying a spectrum scheme, according to some embodiments. [Figure 3A] FIG. 3A shows an example of a lighting device that can be used to emit light according to a particular spectral regime for stress reduction, according to some embodiments. [Figure 3B] FIG. 3B shows an example of a lighting device that can be used to emit light according to a particular spectral regime for stress reduction, according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0012] The following description is presented to enable any person skilled in the art to make and use the disclosed embodiments, and is provided in the context of one or more specific applications and their requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the scope of the disclosure. Thus, the present invention or inventions are not intended to be limited to the embodiments shown, but are to be accorded the widest scope consistent with the disclosure.

[0013] In embodiments disclosed herein, systems, devices, and methods are provided to reduce stress and / or provide other health benefits through intelligent lighting, particularly with respect to color spectrums used to illuminate a room, a portion of a room, a task, a piece of medical equipment, or some other space or item. Different colors or wavelengths of light can be combined in different proportions or ratios to improve well-being by reducing stress and anxiety and / or remaining (relatively) stress-free.

[0014] In some embodiments, discrete light spectrums are applied in medical and related healthcare environments. These applications promote recovery from stressful and / or invasive tests / examinations / medical procedures, including MRI (magnetic resonance imaging), CT (computed tomography) scans, X-rays, colonoscopies, outpatient surgeries, blood draws, and transfusions. For example, the tubular housing of an MRI machine can be configured to predominantly (or exclusively) feature light in a particular portion of the spectrum, providing a relaxing environment of stress-reducing colors. The room or space in which the machine is located can feature the same colors of light, but in different proportions.

[0015] However, other spaces can be similarly configured with the lighting spectrums described herein for the purpose of improving the mental well-being of the humans located in those spaces. For example, the interior of an automobile or other vehicle can be designed to expose the driver and / or passengers to beneficial spectrums and intensities of light. As another example, a student study area can be designed to provide similar benefits.

[0016] Previously, there was a distinct lack of evidence-based data regarding biomarkers, biological / chemical tests, or other measurable factors to support the use of stress-reducing lighting as a recommended practice. Most past studies were anecdotal or involved testing of human subjects using preference-based research methods that often carried cultural biases and / or experimental challenges that limited the general applicability of the observations.

[0017] However, recent research conducted in connection with the development of the embodiments described herein has demonstrated non-visual effects of light on health and well-being, primarily related to circadian and hormonal balance. For example, melanopsin receptors are particularly sensitive to spectral components in the 480 nm region (blue-green), which results in proper suppression of melatonin and circadian entrainment. However, excessive exposure to high levels of light at night, especially in the blue-green spectral region, can negatively impact the circadian system by suppressing melatonin. Conversely, low levels of light at night can mitigate circadian disruptions. Furthermore, it has been shown that near-IR (infrared) radiation in the 750 nm to 1200 nm range can aid in circadian entrainment.

[0018] The embodiments described herein utilize the results of a human subject controlled study using discrete spectra for stress reduction or recovery from stressful events. The primary goal of the study was to identify spectra that reduced cortisol and achieved improved brain wave patterns indicative of stress reduction. In the study, a stressful condition was introduced for each subject, and their brain wave patterns and cortisol levels were monitored (e.g., by EEG (electroencephalography) and saliva testing, respectively) before, during, and after the introduction of the stressful condition, and each subject was exposed to discrete spectrum light after the stress was imposed. The experiment was repeated for a series of colors.

[0019] The test employed a color separation chamber capable of introducing any color spectrum. In this chamber, the lighting system and equipment provided only indirect light, meaning that subjects saw only reflected light and not bare or exposed LEDs, light bulbs, or other intense light sources. The lighting system illuminated the entire chamber so that the selected light spectrum was the only light visible to the subjects.

[0020] Each group of subjects was stressed using a standardized technique. They were then exposed to specific color spectrums, and their cortisol and EEG patterns were monitored throughout. The results demonstrated that (1) discretely introduced amber light spectrum could provide conditions that alleviate or reduce stress in subjects, and (2) testing (using EEG) of asymmetric frontal lobe alpha waves (8 Hz-12 Hz) between the right and left hemispheres showed that light concentrated in the amber region had the greatest and most positive impact on stress reduction.

[0021] FIG. 1 illustrates the recovery rates of stressed subjects from the aforementioned study during exposure to different light spectra. Recovery graph 100 shows the normalized alpha lateralization index (RH-LH) over time for each of several spectrums, represented as amber 110, white 112, red 114, green 116, and blue 118. Amber plot 110 corresponds to recovery light within the 570-680 nm range, white plot 112 corresponds to recovery light within the ? range, red plot 114 corresponds to recovery light within the 440-700 nm range, green plot 116 corresponds to recovery light within the 500-560 nm range, and blue plot 118 corresponds to recovery light within the 440-480 nm range. Thus, graph 100 demonstrates that applying light within discrete spectrums to subjects recovering from a stressful event had a clear impact.

[0022] The study was conducted in an enclosed room approximately 8 feet wide, 8 feet long, and 9 feet high. The walls and ceiling featured a matte white finish with high reflectivity (approximately 80% to 85%). Two rows of four-channel color-changing RGBA (red, green, blue, alpha channel (to represent opacity)) luminaires were mounted horizontally on the four walls, 6.5 feet above the finished floor (AFF), to generate indirect lighting reflected from the ceiling and the top and bottom walls. A total of 16 4-foot-long fixtures, each with a 100° x 100° beam distribution, were installed inside the room but concealed behind a fascia that protruded 4 inches from the wall.

[0023] This configuration helped to avoid potential glare for participants and created evenly distributed lighting throughout the space. More specifically, the illuminance of the lighting (e.g., when amber spectrum was emitted) was 50 lux (approximately 5 foot candles) at task height (approximately 2.5 ft AFF), sufficient to be visually comfortable without high contrast and without direct line of sight to the lighting fixture.

[0024] Beyond identifying light spectrums that are particularly effective in reducing stress (e.g., amber light in the range of 570 nm to 680 nm (and especially 580 nm to 600 nm)), research has also shown the desirability of avoiding or limiting other spectrums. For example, the effects of amber wavelength light are most pronounced when amber light constitutes 100% of the luminous flux perceived by a stressed individual, but can still provide significant benefits even when amber light is reduced to approximately 80% to 85% of the total luminous flux.

[0025] However, if the amber light spectrum accounts for less than 100% of the flux, wavelengths above amber (e.g., 680 nm and above) should be at most 10% of the total flux, the green wavelength region (e.g., 510 nm to 540 nm) should be at most 5% of the total flux, and light flux below 510 nm (corresponding to cyan blue) should not be included.

[0026] Within these boundaries, lighting for areas, tasks, equipment, etc. can be adjusted for purposes other than stress relief or reduction. For example, certain components of the light experienced by a person can be designed to affect the person's ability to perform a task (e.g., driving, reading, working with tools, etc.).

[0027] Allowing up to 15% of the light spectrum outside the amber region can create a more natural setting in which a person is more likely to observe colors and patterns and perform expected tasks. Of course, a narrower spectral distribution (100% or closer to 100% amber) may be desired if the primary or only concern is improving a person's mental state during or after a stressful event or process.

[0028] As such, the lighting devices and systems described herein can be programmed to emit light according to these and / or other constraints (e.g., detected or observed stress levels, hours the lighting device / system is operational, etc.). For example, the location or space in which stress-reducing lighting is installed can include one or more sensors that automatically sample light and measure its components. If the flux percentage in the amber region falls or threatens to fall below 80%, the lighting system can stop emitting light of other wavelengths or adjust the emitted ratio of light in different color regions. Illustratively, sunlight may enter the space (e.g., through a window or window treatment surround), white light may leak into the space from an adjacent space or through a door, or the lighting in the space may change in some other way. By detecting changes in lighting, the system can automatically make corrections within programmed thresholds and parameters.

[0029] 2 is a flowchart illustrating a method of applying a spectral approach to produce stress-relief benefits, according to some embodiments. One or more of the illustrated steps may be omitted, repeated, and / or performed in a different order. Thus, the specific arrangement of steps shown in FIG. 2 should not be construed as limiting the scope of the embodiments.

[0030] In operation 202, a room, a portion of a room, a workspace, a seating area in a vehicle, a portion of a facility (e.g., a medical facility), or some other space is retrofitted with a system including one or more devices for emitting light in one or more color (or wavelength) ranges excluding (or in addition to) white. For example, one or more lighting devices (e.g., LEDs, lamps, light tubes, spotlights, etc.), as described further below, can be installed to support the illustrated method. This device can be integral to the space or facility (e.g., built into the space or facility during construction) or can be added after the space or facility is constructed.

[0031] In operation 204, one or more controllers are programmed or otherwise configured to control the operation of the lighting devices. In some embodiments, the controllers are contained within the lighting devices, while in other embodiments, the system includes a hardware or software controller (e.g., a DMX controller) that is external to the lighting devices and can control any or all of the respective devices.

[0032] In the illustrated embodiment, programming the controller can include configuring the controller to have one or more preset options for light emitted by the lighting device, particularly regarding color / wavelength, but possibly also regarding intensity, operating time, automatic transition from one lighting mix to another, etc. As used herein, lighting mix or ratio refers to the mix or ratio of flux from different parts of the light spectrum that are combined to produce the light output by the lighting system. Thus, a first mix may consist of only amber light. A second mix may consist of (approximately) 85% amber light, 5% green light, and 10% red light. Other mixes can combine any colors in any desired ratio. The controller can also (or instead) be manually manipulated to vary the mix as desired during operation.

[0033] In optional operation 206, the lighting system and / or one or more individual lighting devices are limited by a lighting scheme (e.g., via programming in a controller) that ensures that emitted light is always configured to produce the aforementioned stress-relief benefits. More specifically, when so limited, during operation of the system or device, the total emitted luminous flux always includes between 80% and 100% amber (e.g., 570 nm - 680 nm) flux. Furthermore, no light below 510 nm is emitted, the green region (e.g., 510 nm - 550 nm) accounts for less than 5% of the total luminous flux, and wavelengths above 680 nm account for less than 10% of the total luminous flux.

[0034] In operation 208, the lighting system is activated manually or automatically. For example, if part of a medical facility (e.g., an MRI machine), the lighting system may activate when the facility is powered on or when a patient is located inside or near the facility. If part of a vehicle, the lighting system may activate when the vehicle is turned on, when the vehicle is occupied, or when the vehicle begins to move. If part of a room or space, the lighting system may activate when occupied by one or more people, when a need for stress reduction is expressed, or periodically (e.g., operating at certain times of day). In some embodiments, the stress-reducing lighting mix is ​​activated when a person activates a controller (e.g., by activating a switch).

[0035] In operation 210, the lighting mix output by the lighting system can be varied over time, automatically and / or manually, subject to any applicable limitations, such as those described above. For example, if the system is illuminating a medical recovery room, the system may initially emit only (or mostly only) amber light to provide maximum stress-reducing benefits. After a period of time (e.g., minutes, hours), the mix can be changed to include some other color of light, for example, to facilitate a task (such as reading), to display a color that the patient finds calming or soothing, or for some other reason.

[0036] Similarly, a lighting system in another space (e.g., a car, a study area) could begin operating with light containing less flux in the amber region of the spectrum and more flux of some other discrete color or white, but then transition to an increasing proportion of amber light over time, perhaps as more stress is detected or a stressful event is encountered.

[0037] Additionally, the programmed (and / or manual) limits can be active all the time, or only at certain times. For example, a room can be naturally lit with sunlight or white light during some time of the day, such as in the morning. The limits can then be activated (if necessary, along with blinds or other window coverings to block out the sunlight), thereby providing stress reduction or relief. Operation 210 can continue indefinitely, or the lighting system can be powered off when not needed (e.g., overnight, between patients).

[0038] In optional operation 212, biometric data can be collected from one or more people viewing light from the lighting system. Different embodiments can employ different collection methods, such as saliva testing, observing pupil size, measuring pulse, identifying facial expressions, or measuring brain wave patterns using EEG. The data can indicate that the lighting mix should be changed to increase or decrease the stress-reducing effect (e.g., by increasing or decreasing the proportion of amber light), or that the current mix is ​​providing the desired benefit and does not need to be changed. Thus, after operation 212, the method can return to operation 210 or end.

[0039] The lighting systems provided herein can include any number of lighting fixtures capable of emitting light of any desired color, which may or may not include white light. For example, in the aforementioned study, multiple wall-mounted fixtures were used around the perimeter of an enclosed space (room). Each fixture consisted of four LEDs or LED chips that generated red, green, blue, and amber light, respectively. A DMX (digital multiplexing) controller controlled which LEDs were active for a given time and their relative intensities when colors other than red, green, blue, and amber were desired.

[0040] 3A-3B illustrate lighting devices for providing stress-reducing benefits provided in some embodiments. The devices shown in FIG. 3A can be controlled (e.g., with respect to the color and intensity of the light they emit) by controller 302. The devices in FIG. 3B can be controlled by a controller internal to the device or by an external controller, such as controller 302. Controller 302 can communicate with the individual lighting devices via wired and / or wireless technologies and protocols.

[0041] One or more ceiling panels 312 can illuminate an area with diffused and colored light and can be suspended from the ceiling or flush with the ceiling surface. Wall luminaires 314 can provide direct light or, as in the aforementioned study, can provide indirect light when installed behind a fascia or other partial covering.

[0042] Flexible nodes 316 provide a random arrangement of lights providing stress-reducing colored light, floodlights 318 allow for direct or indirect illumination of relatively large areas, and table lamps 320 and floor lamps or floor stands 322 allow for the projection of stress-reducing light in relatively small areas, for example for localized benefit to a person performing a task.

[0043] The vehicle 330 (e.g., an automobile) may include lighting equipment or devices for the benefit of the vehicle driver and / or passengers. Lighting within the vehicle 330 may cooperate with window tinting technology and / or may operate primarily when the light emitted by the interior devices is not dominated by external light (e.g., during the day). In some embodiments, stress-reducing lighting within the vehicle 330 may be located on the roof to provide diffused lighting throughout many or all passenger compartments. In other embodiments, lighting may be emitted, for example, by door panels, under the dashboard, under or behind seats, the floor, etc. To avoid distracting or blinding the vehicle driver, some or all light sources may be hidden or covered to provide primarily or only indirect light.

[0044] In the MRI machine 340, stress-reducing lighting is incorporated into (or added to) the bore in which the patient lies. For example, one or more light sources can be located inside the bore and / or placed outside the bore to shine light into the bore. A different light color and / or intensity can be used outside the bore. For example, inside the bore, all or nearly all of the light flux perceived by the patient can be in a known color region, such as amber. Outside the bore, the flux mix can employ less than 100% amber, perhaps to assist the technician or medical personnel working with the patient.

[0045] Thus, in some embodiments, multiple LEDs (light-emitting diodes) are controlled (singly and / or in groups) to dynamically generate a desired range of color spectra, with the ability to adjust both intensity and timing (in addition to color). For example, a semiconductor chip containing multiple LEDs for emitting light of different wavelengths and circuitry for controlling the emission of light can be easily incorporated into almost any lighting device or any fixture that features or can feature interior lighting. Depending on the type of lighting device used (e.g., indirect wall sconce, ceiling light, table / floor lamp), discrete color control within a relatively narrow range of spectral distribution can be provided for an area of ​​any size to achieve the desired result. LED chips or other similar lighting components can also be integrated into dedicated fixtures and supporting hardware, such as MRI machines.

[0046] The foregoing embodiments have been presented for purposes of illustration and description only. They are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Accordingly, many modifications and variations will be apparent to those skilled in the art. The scope of the present disclosure is defined by the appended claims, not by the foregoing disclosure.

Claims

1. one or more light emitting devices; a controller for controlling the overall light emitted by the light emitting device and mitigating stress experienced by one or more people observing the overall light; Equipment having:

2. 10. The device of claim 1, wherein the one or more light emitting devices comprise a plurality of light emitting diodes (LEDs).

3. 10. The apparatus of claim 1, wherein the light emitting device is selectively operable so that the total light comprises a single region of the visible light spectrum.

4. 4. The device of claim 3, wherein the single region of the visible light spectrum comprises the wavelength region from 570 nm to 680 nm.

5. 10. The apparatus of claim 1, wherein the light emitting device is selectively operable such that the overall light comprises a mixture of multiple regions of the visible light spectrum while excluding one or more other regions of the visible light spectrum.

6. 6. The apparatus of claim 5, wherein the plurality of regions includes a wavelength region from 570 nm to 680 nm, and one or more of: (a) a wavelength region from 510 nm to 540 nm, and (b) a wavelength region greater than 680 nm.

7. 7. The device of claim 6, wherein the other one or more regions include a wavelength region below 510 nm.

8. 10. The apparatus of claim 1, wherein the light emitting device comprises one or more area lighting fixtures that provide indirect light to the one or more people.

9. 10. The apparatus of claim 1, wherein the light emitting device comprises one or more area lamps.

10. The device of claim 1 , wherein the device is a vehicle.

11. The device of claim 1 , wherein the device comprises medical equipment.

12. The medical equipment includes: an MRI (magnetic resonance imaging) device; CT (computed tomography) scanner, an X-ray device; Blood transfusion facilities, a medical display device; 12. The device of claim 11, comprising at least one of:

13. activating one or more light sources capable of emitting light in selected wavelength regions of the visible light spectrum; Controlling the overall emission of the one or more light sources to reduce human stress; The method includes:

14. 14. The method of claim 13, wherein said controlling comprises controlling said light source such that a first wavelength region between 570 nm and 680 nm accounts for at least 80% of said total emission.

15. 15. The method of claim 14, wherein the controlling further comprises controlling the light source so that a wavelength region between 510 nm and 540 nm accounts for less than 5% of the total emission.

16. 15. The method of claim 14, wherein the controlling further comprises controlling the light source so that a wavelength region greater than 680 nm accounts for less than 10% of the total emission.

17. 15. The method of claim 14, wherein the controlling further comprises controlling the light source such that the overall emission does not include light in a wavelength region below 510 nm.

18. measuring a stress level of said human subject; adjusting the overall output in accordance with the measured stress level; The method of claim 13 further comprising:

19. 20. The method of claim 18, wherein adjusting the overall output comprises increasing a proportion of a first wavelength region.

20. 14. The method of claim 13, wherein the controlling comprises increasing or decreasing the intensity of one or more wavelength regions of the overall output.

21. a seat for one or more persons; one or more light emitting devices; a controller for controlling a configuration of light emitted by the one or more light emitting devices to reduce a stress level of the one or more persons; A vehicle having:

22. The controller is configured to: A green flux in the wavelength range of 510 nm to 540 nm; Amber flux in the wavelength range of 570 nm to 680 nm; A red flux in the wavelength region above 680 nm; 22. The vehicle of claim 21, operable to include one or more of:

23. the amber flux accounts for 80% or more of the light emitted by the one or more light emitting devices; the green flux accounts for 5% or less of the light emitted by the one or more light emitting devices; 23. The vehicle of claim 22, wherein the red bundle comprises 10% or less of the light emitted by the one or more light emitting devices.

24. 23. The vehicle of claim 22, wherein the light emitted by the one or more light emitting devices does not include luminous flux below 510 nm.

25. 22. The vehicle of claim 21, wherein the configuration of light emitted by the one or more light emitting devices can be selected by the one or more people.

26. 22. The vehicle of claim 21, wherein the configuration of light emitted by the one or more light emitting devices is automatically adjusted by the controller based on a measurement of a stress level of the one or more persons.

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