Human Physiological Responses Research Articles

Differences in Human Thermal and Physiological Responses under Corridor and Greenway in Summer in Guangzhou

As urbanization and the heat island effect intensify, comfortable and healthy outdoor micro-environments are particularly important for sustainable urban development, encouraging more outdoor activities. Fewer studies have focused on differences in thermal comfort and thermal physiology of users in potential outdoor open spaces. Therefore, this study aims to examine the differences in thermal comfort and thermal stress among users of common outdoor open shady spaces, contributing towards a better thermal experience and mitigating heat stress. In this study, a field investigation of corridors and greenways was conducted on a campus in Guangzhou in the summer based on subjective questionnaires and objective measurements of thermal environment, and thermal physiological parameters. The results found that people were more likely to experience good thermal comfort and weaker intensity of thermal stress in corridors with significant differences in physiological responses. Furthermore, the upper limit comfort temperatures of the corridor and greenway were 34.0 and 33.4 °C, respectively. In addition, it can be concluded that the corridor was a more optimal space for outdoor shade before evening, whereas the greenway was more optimal in the evening in summer. The findings determine the thermal benchmarks for typical outdoor shady spaces in hot and humid regions in summer, which can help designers create comfortable outdoor public spaces that improve thermal comfort and people's health.

Advancing Sentiment Analysis Through Emotionally-Agnostic Text Mining in Large Language Models (LLMS)

The conventional methodology for sentiment analysis within large language models (LLMs) has predominantly drawn upon human emotional frameworks, incorporating physiological cues that are inherently absent in text-only communication. This research proposes a paradigm shift towards an emotionallyagnostic approach to sentiment analysis in LLMs, which concentrates on purely textual expressions of sentiment, circumventing the confounding effects of human physiological responses. The aim is to refine sentiment analysis algorithms to discern and generate emotionally congruent responses strictly from text-based cues. This study presents a comprehensive framework for an emotionally-agnostic sentiment analysis model that systematically excludes physiological indicators whilst maintaining the analytical depth required for accurate emotion detection. A novel suite of metrics tailored to this approach is developed, facilitating a nuanced interpretation of sentiment within text data, which is paramount for enhancing user interaction across a spectrum of text mining applications, including recommendation systems and interactive AI characters. The research undertakes a critical comparative analysis, juxtaposing the newly proposed model with traditional sentiment analysis techniques, to evaluate efficacy enhancements and to substantiate its application potential. Further, the investigation delves into the short-term memory capabilities of LLMs, exploring the implications for character AI roleplaying interfaces and their ability to recall and respond to user input within a text-driven emotional framework. Findings indicate that this emotionally-agnostic sentiment analysis approach not only simplifies the sentiment assessment process within LLMs but also opens avenues for a more precise and contextually appropriate emotional response generation. This abstracted model, devoid of human physiological constraints, represents a significant advancement in text mining, fostering improved interactions and contributing to the evolution of LLMs as adept analytical tools in various domains where emotional intelligence is crucial.

The Surgical Stress Response and Anesthesia: A Narrative Review.

The human physiological response "to stress" includes all metabolic and hormonal changes produced by a traumatic event at the micro or macro cellular levels. The main goal of the body's first response to trauma is to keep physiological homeostasis. The perioperative non-specific adaptation response can sometimes be detrimental and can produce systemic inflammatory response syndrome (SIRS), characterized by hypermetabolism and hyper catabolism. We performed a narrative review consisting of a description of the surgical stress response's categories of changes (neurohormonal and immunological response) followed by reviewing methods found in published studies to modulate the surgical stress response perioperatively. We described various preoperative measures cited in the literature as lowering the burden of surgical trauma. This article revises the anesthetic drugs and techniques that have an impact on the surgical stress response and proven immune-modulatory effects. We also tried to name present knowledge gaps requiring future research. Our review concludes that proper preoperative measures, adequate general anesthetics, multimodal analgesia, early postoperative mobilization, and early enteral nutrition can decrease the stress response to surgery and ease patient recovery. Anesthetics and analgesics used during the perioperative period may modulate the innate and adaptive immune system and inflammatory system, with a consecutive impact on cancer recurrence and long-term outcomes.

The Relationship of Hot Work Climate on Physiological Response in Traditional Clover Leaf Oil Refining Workers

In the clove leaf oil refining process which uses steam, it produces a hot temperature residue which affects clove leaf oil refinery workers. Exposure to a hot working climate can have an impact on human physiological responses such as an increase in body temperature, pulse rate, blood pressure and weight loss. as a result of producing quite a lot of sweat fluid. This research aims to investigate the physiological responses of clove leaf oil refinery workers to exposure to a hot working climate. In the clove leaf oil refining process, which utilizes steam, the production of hot temperature residue affects the workers. Exposure to such conditions can lead to various physiological responses, including increased body temperature, pulse rate, blood pressure, and weight loss due to significant sweating. Employing a quantitative research design with a cross-sectional analytical approach, data were collected from all 22 workers using a total sampling technique. The primary data collected were subjected to analysis using paired simple t-tests and the Pearson correlation test to explore relationships between variables. The findings reveal significant increases in physiological responses post-work, including elevated body temperature, pulse rate, systolic and diastolic blood pressure, and a reduction in body weight. The obtained p-values for all variables were <0.05, indicating statistically significant differences between pre-work and post-work conditions. Furthermore, the Pearson correlation test analysis between heat stress data and post-work physiological responses, including body temperature, pulse rate, systolic and diastolic blood pressure, as well as body weight, revealed moderate to strong correlations (r). These results underscore the detrimental impact of hot working climates on the physiological well-being of clove leaf oil refinery workers. Such findings highlight the urgent need for implementing appropriate measures to mitigate heat-related health risks in occupational settings, safeguarding the health and safety of workers.

Study on personal comfort heating system and human thermal comfort in extremely low-temperature building environments

Exposure to extremely low-temperature building environments around −20 °C causes various hazards to human health. However, few studies have studied human thermal comfort and physiological response in such environments, nor the personal comfort heating system. Thus, this study investigated the heating characteristics of personal comfort heating system and their effects on thermal responses and thermophysiological parameters in extremely low-temperature building environments. We conducted experimental tests and questionnaires in a cryogenic enthalpy difference laboratory with air temperature ranging from −21.2 to −15.6 °C and a relative humidity of 55 %. Eight experimental conditions were designed with several heating measures (heating mat, heating gloves, heating cushion and airwarmer). The heating parameters of the personal comfort heating systems as well as the subjective evaluations and skin temperature of the subjects were recorded and analyzed. The results showed that the airwarmer confinement box condition had a corrective power of up to 38.3 K. The overall thermal sensation vote and overall thermal comfort vote were maintained at 0.25 and −0.25. Further, we found that the face, hands, calves and feet got cold easier with the largest skin temperature difference of −4.9, −8.1, −6.7 and −7.6 °C, respectively. Besides, the relationships between thermal responses and between thermal responses and skin temperature were examined, as well as a thermal comfort assessment methodology was established for extremely low-temperature environments.

Characterizing Glomerular Barrier Dysfunction with Patient-Derived Serum in Glomerulus-on-a-Chip Models: Unveiling New Insights into Glomerulonephritis.

Glomerulonephritis (GN) is characterized by podocyte injury or glomerular filtration dysfunction, which results in proteinuria and eventual loss of kidney function. Progress in studying the mechanism of GN, and developing an effective therapy, has been limited by the absence of suitable in vitro models that can closely recapitulate human physiological responses. We developed a microfluidic glomerulus-on-a-chip device that can recapitulate the physiological environment to construct a functional filtration barrier, with which we investigated biological changes in podocytes and dynamic alterations in the permeability of the glomerular filtration barrier (GFB) on a chip. We also evaluated the potential of GN-mimicking devices as a model for predicting responses to human GN. Glomerular endothelial cells and podocytes successfully formed intact monolayers on opposite sides of the membrane in our chip device. Permselectivity analysis confirmed that the chip was constituted by a functional GFB that could accurately perform differential clearance of albumin and dextran. Reduction in cell viability resulting from damage was observed in all serum-induced GN models. The expression of podocyte-specific marker WT1 was also decreased. Albumin permeability was increased in most models of serum-induced IgA nephropathy (IgAN) and membranous nephropathy (MN). However, sera from patients with minimal change disease (MCD) or lupus nephritis (LN) did not induce a loss of permeability. This glomerulus-on-a-chip system may provide a platform of glomerular cell culture for in vitro GFB in formation of a functional three-dimensional glomerular structure. Establishing a disease model of GN on a chip could accelerate our understanding of pathophysiological mechanisms of glomerulopathy.

Impact of Indoor Air Quality and Multi-domain Factors on Human Productivity and Physiological Responses: A Comprehensive Review

Indoor environmental quality (IEQ) significantly impacts human health, well-being, and productivity. However, a comprehensive and in-depth review of the combined effects of IAQ and other multi-domain factors on human productivity is lacking. There has not been any prior review that encapsulates the impact of multi-domain factors on productivity and physiological responses of occupants. To address this gap, this review paper investigates and highlights the impact of IAQ and multi-domain factors (thermal, visual, and acoustic) on human productivity and occupant well-being in the built environment. The review explores various research methods, including evaluation of human productivity and creativity, data collection, and physiological signal analysis. We also examined the interactions between IAQ and multi-domain factors, as well as strategies for optimizing productivity through integrated building design and smart systems. The key findings from this review reveal that IAQ significantly impacts human productivity and occupant well-being, with interactions between IAQ and other IEQ factors further impacting these effects. Despite advances in the field, there are several limitations and gaps in the current research methods and study designs, including small sample sizes, limited and insufficient experimental design and control, reliance on laboratory or simulated environments, lack of follow-up and long-term data, and lack of robust performance metrics. The review proposes future research directions, including specific applications, and follow-up work to address these limitations and further advance the understanding of IAQ and multi-domain factors in the built environment. The implications of this review for policy and practice include the need for holistic and integrated approaches to IAQ and IEQ management, with a focus on creating healthy and productive indoor environments. This review emphasizes the importance of considering the complex interplay between IAQ and multi-domain factors, as well as the potentials of adopting smart control systems and sustainable design strategies to optimize productivity and occupant well-being in the built environment. By addressing these critical issues, we can enhance the overall quality of life for building occupants and contribute to a more sustainable future.

Exploring the impact of computer-mediated emotional interactions on human facial and physiological responses

Remote communication has become pervasive, yet its impact on human emotions, empathy, and physiological responses remains unclear. This study addresses this gap by investigating how emotional video-mediated conversations differ from face-to-face interactions, focusing on behavioral and physiological responses. We create a multimodal dataset of Electrodermal Activity (EDA) signals, Photoplethysmography (PPG) signals, and facial videos from two people conversing about emotional topics in face-to-face and remote video-mediated conditions. We use a series of repeated measures ANOVA with aligned rank transform to compare face-to-face to remote conversation in terms of heart rate activity, electrodermal activity, and facial action units. We also explore how subjective empathy between people varies in these two conditions. Our findings reveal significant differences in physiological responses between face-to-face and remote conversation and variations in perceived empathy based on interaction setting, highlighting the nuanced influence of communication channels. We also show that we can recognize emotions more accurately when we pre-train a random forest classifier with one condition’s data (an increase of 20% to 45% for various modalities). Finally, we discuss the research findings and limitations and offer insights for optimizing human–computer interaction and understanding human emotional responses in an increasingly tech-mediated world.

Exploring on the prediction model of human skin temperature and rectal temperature under heat stress

Hot environments cast direct influence on people's well-beings and health besides working productivity during the accelerating global warming. The systematic mechanism is not entirely clear due to the complex human physiological response which also handled human heat strain protection. This study carries out mathematical derivation on the rectal temperature and skin temperature under human heat strain based on the PHS model of ISO 7933 standard. The experimental validation was conducted in a climate chamber with continuously monitoring the typical physiological parameters of 10 subjects in 9 hot working environments. Physiological parameters of subjects were analyzed on average difference (AV), coefficient of variation (CV) and skewness (SKEW) to explore their mutual linkages. Both experimental and theoretical result shows that certain relationship existed between the rectal temperature and skin temperature. The Poisson's ratio on their average value, coefficient of variation, average difference and skew were 0.957, 0.991, 0.990 and 0.941 respectively. Linear relation with coefficient of 0.73 was found between rectal temperature and skin temperature coupling with the constant of 12.09. Comparison on the dynamic changes of rectal temperature and skin temperature was carried out and verified under PHS model. The results showed that rectal temperature was adjusted earlier and more forcefully than skin temperature indicating that human core temperature was better protected under heat stress. The findings contribute to a convenient method of human heat strain prediction when taking rectal temperature as the best physiological threshold with fast human skin temperature and environment parameters monitoring in complex high temperature working environments.

High-temperature and thermal radiation affecting human thermal comfort and physiological responses: An experimental study

Hot environments with high temperatures and thermal radiation are to be found in heat treating, glass melting workshops, etc., which impacts worker thermal comfort and physiological responses. The motivation of this study was to explore the changes of thermal comfort in a high-temperature and thermal radiation environment. Four experimental cases were designed to simulate high temperatures and thermal radiation. Physiological parameters such as skin temperature, ear cancel temperature, heart rate, and weight loss were investigated. Evaporative heat losses and skin wettedness were calculated by Gagge's two node model or weight loss. The results showed that local and mean skin temperatures increased by approximately 4 °C during the exposure. Thermal sensation vote was positively correlated with WBGT. The dynamic relationship between human heat gain, evaporative heat loss and potential thermal risk was framed as Stage A, Stage B, and possibly Stage C. This study could provide the basic information and theoretical evidence for the thermal comfort and thermal risk in high-temperatures and thermal radiation environment.

Lifejackets or just jackets? Seaworthiness of lifejackets sold at landing sites of Lake Albert, Uganda

ABSTRACT Objectives. Upon immersion in water, a cascade of human physiological responses is evoked, which may result in drowning death. Although lifejackets are over 80% effective in preventing drowning, many people in lakeside fishing communities in Uganda shy away from wearing them because of active distrust in the quality of the lifejackets on the local market. No study has determined the veracity of these claims. This study determined the seaworthiness of lifejackets sold at landing sites of Lake Albert, Uganda. Methods. Using a within-person repeated assessment design, we tested 22 new lifejacket samples obtained from landing sites of Lake Albert, Uganda. We conducted water entry, righting, floatation stability and minimum buoyancy performance tests. Results. All the lifejacket samples failed the minimum buoyancy functional requirements test; the average buoyancy was 80 N (SD 13). Only 4% of the lifejackets passed the righting test within 5 s. For floatation stability, 45% of the lifejackets sank earlier than 48 h of placement in water and also failed water entry tests by getting dislodged from the wearer. Conclusion. The lifejackets sold at the landing sites of Lake Albert do not meet minimum seaworthiness functional requirements. The government should regulate the quality of lifejackets on the local market.

Methods for Selecting Design Alternatives through Integrated Analysis of Energy Performance of Buildings and the Physiological Responses of Occupants

We propose a technique that allows designers to develop energy-efficient buildings focused on occupants from the early design stage. The technique integrates the physiological responses of occupants and the energy performance of buildings. Among the architectural design elements, we considered the aspect ratio, ceiling height, and window-to-wall ratio as design variables and created 30 design alternatives for a single-occupancy room in a postpartum care center. These design alternatives were recreated in virtual reality, allowing 33 female participants to immerse themselves in the designed rooms. During the experiment, we collected electroencephalography (EEG) data from the participants. Furthermore, we used DesignBuilder to simulate 30 design alternatives and calculated the primary energy consumption per unit area for each alternative. By integrating the EEG data and energy performance analysis, we identified the design alternative among the 30 options that positively influenced the physiological responses of occupants while also being energy efficient. The selected alternative was designed with an aspect ratio of 1:1.6, a ceiling height of 2.3 m, and a window-to-wall ratio of 60%. This research represents a creative exploration that demonstrates how studies combining human physiological responses and architecture can evolve through integration with other subjects. Our findings provide a robust framework to explore the relationship between physiological responses and energy optimization for detailed architectural design elements.

VR communication simulation with scripted dialog elicits HPA axis stress

Stress-inducing virtual reality (VR) systems have various applications in research, ranging from training to therapy to the observation of biological stress responses. Stress in VR can be evoked through environmental, cognitive, and social stimuli. Although various VR tasks can induce an autonomic nervous system (ANS) stress response, hypothalamic-pituitary-adrenal (HPA) axis stress responses have only been confirmed in VR for the virtual Trier social stress test (V-TSST). Understanding the impact of a wider variety of tasks on HPA-axis stress response could lead to the development of more effective stress relief measures and treatments. This study aims to clarify whether a virtual communication simulation, using a static procedure with a predetermined dialog, can evoke an HPA-axis stress response. Employing a virtual customer service system, we varied the intensity of the presented stress by changing the tone and gestures of the virtual customer. The findings confirm that HPA-axis stress responses can be elicited by such static virtual customer service training systems, and the stress responses can be adjusted by altering the avatar’s attitude. These findings suggest potential applications in research for observing human physiological responses to stress and development of stress reduction strategies, thereby affirming the effectiveness of VR in communication training.

Site-specific thrombus formation: advancements in photothrombosis-on-a-chip technology.

Thrombosis, characterized by blood clot formation within vessels, poses a significant medical challenge. Despite extensive research, the development of effective thrombosis therapies is hindered by substantial costs, lengthy development times, and high failure rates in medication commercialization. Conventional pre-clinical models often oversimplify cardiovascular disease, leading to a disparity between experimental results and human physiological responses. In response, we have engineered a photothrombosis-on-a-chip system. This microfluidic model integrates human endothelium, human whole blood, and blood flow dynamics and employs the photothrombotic method. It enables precise, site-specific thrombus induction through controlled laser irradiation, effectively mimicking both normal and thrombotic physiological conditions on a single chip. Additionally, the system allows for the fine-tuning of thrombus occlusion levels via laser parameter adjustments, offering a flexible thrombus model with varying degrees of obstruction. Additionally, the formation and progression of thrombosis noted on the chip closely resemble the thrombotic conditions observed in mice in previous studies. In the experiments, we perfused recalcified whole blood with Rose Bengal into an endothelialized microchannel and initiated photothrombosis using green laser irradiation. Various imaging methods verified the model's ability to precisely control thrombus formation and occlusion levels. The effectiveness of clinical drugs, including heparin and rt-PA, was assessed, confirming the chip's potential in drug screening applications. In summary, the photothrombosis-on-a-chip system significantly advances human thrombosis modeling. Its precise control over thrombus formation, flexibility in the thrombus severity levels, and capability to simulate dual physiological states on a single platform make it an invaluable tool for targeted drug testing, furthering the development of organ-on-a-chip drug screening techniques.

Problems associated with creating special software for simulating of human physiological responses to dynamic accelerations

Under extreme accelerations, human physiological mechanisms cannot provide adequate circulation. Special methods and devices protecting pilot’s brain and eye functionality have been proposed but their efficiency is individual and depends on pilot’s skills. Currently, the lonely technology to safely acquire and test the necessary skills is based on use of special centrifuges. However, lack of adequate data about physiological and biomechanical events are two main causes worsening the training results. Special computer simulators, capable to model and visualize the main mechanical and physiological effects occurring under dynamic accelerations, could increase the effectiveness of future pilot’s training process. This publication aims to define fundamental problems concerned with creating the required software. There exist two main groups of problems. The first group is concerned with the necessity to create basic mathematical models quantitatively describing both the physiological events and effects induced by protective maneuvers. Here special logical procedures, individualizing the basic physiological models, have to be proposed. The second group of problems is predominantly technical and associated with the necessity of special user interface (SUI) development. SUI must be subdivided into two functional sections – one for preparing a single computer experiment (simulation), and another – for analyzing the results of simulation. An experiment preparation includes the following events: i) a preliminary tuning of models according to biometrical data; ii) a setting of acceleration profile; iii) a choosing of protective algorithms and tools (or without protections); iv) a choosing of forms for results storage. Graphs presenting the dynamics of input and output variables are the main forms while the table forms are also included. The user (trainer or trainee) will be able to retrieve from the memory graphs of previous simulations to compare the effectiveness of additional protective elements. The software must be autonomic for the Windows platform.

FRESH™ 3D bioprinted cardiac tissue, a bioengineered platform for in vitro pharmacology.

There is critical need for a predictive model of human cardiac physiology in drug development to assess compound effects on human tissues. In vitro two-dimensional monolayer cultures of cardiomyocytes provide biochemical and cellular readouts, and in vivo animal models provide information on systemic cardiovascular response. However, there remains a significant gap in these models due to their incomplete recapitulation of adult human cardiovascular physiology. Recent efforts in developing in vitro models from engineered heart tissues have demonstrated potential for bridging this gap using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) in three-dimensional tissue structure. Here, we advance this paradigm by implementing FRESH™ 3D bioprinting to build human cardiac tissues in a medium throughput, well-plate format with controlled tissue architecture, tailored cellular composition, and native-like physiological function, specifically in its drug response. We combined hiPSC-CMs, endothelial cells, and fibroblasts in a cellular bioink and FRESH™ 3D bioprinted this mixture in the format of a thin tissue strip stabilized on a tissue fixture. We show that cardiac tissues could be fabricated directly in a 24-well plate format were composed of dense and highly aligned hiPSC-CMs at >600 million cells/mL and, within 14 days, demonstrated reproducible calcium transients and a fast conduction velocity of ∼16 cm/s. Interrogation of these cardiac tissues with the β-adrenergic receptor agonist isoproterenol showed responses consistent with positive chronotropy and inotropy. Treatment with calcium channel blocker verapamil demonstrated responses expected of hiPSC-CM derived cardiac tissues. These results confirm that FRESH™ 3D bioprinted cardiac tissues represent an in vitro platform that provides data on human physiological response.

An analysis of physiological responses as indicators of driver takeover readiness in conditionally automated driving

By the year 2045, it is projected that Autonomous Vehicles (AVs) will make up half of the new vehicle market. Successful adoption of AVs can reduce drivers’ stress and fatigue, curb traffic congestion, and improve safety, mobility, and economic efficiency. Due to the limited intelligence in relevant technologies, human-in-the-loop modalities are still necessary to ensure the safety of AVs at current or near future stages, because the vehicles may not be able to handle all emergencies. Therefore, it is important to know the takeover readiness of the drivers to ensure the takeover quality and avoid any potential accidents. To achieve this, a comprehensive understanding of the drivers’ physiological states is crucial. However, there is a lack of systematic analysis of the correlation between different human physiological responses and takeover behaviors which could serve as important references for future studies to determine the types of data to use. This paper provides a comprehensive analysis of the effects of takeover behaviors on the common physiological indicators. A program for conditional automation was developed based on a game engine and applied to a driving simulator. The experiment incorporated three types of secondary tasks, three takeover events, and two traffic densities. Brain signals, Skin Conductance Level (SCL), and Heart Rate (HR) of the participants were collected while they were performing the driving simulations. The Frontal Asymmetry Index (FAI) (as an indicator of engagement) and Mental Workload (MWL) were calculated from the brain signals to indicate the mental states of the participants. The results revealed that the FAI of the drivers would slightly decrease after the takeover alerts were issued when they were doing secondary tasks prior to the takeover activities, and the higher difficulty of the secondary tasks could lead to lower overall FAI during the takeover periods. In contrast, The MWL and SCL increased during the takeover periods. The HR also increased rapidly at the beginning of the takeover period but dropped back to a normal level quickly. It was found that a fake takeover alert would lead to lower overall HR, slower increase, and lower peak of SCL during the takeover periods. Moreover, the higher traffic density scenarios were associated with higher MWL, and a more difficult secondary task would lead to higher MWL and HR during the takeover activities. A preliminary discussion of the correlation between the physiological data, takeover scenario, and vehicle data (that relevant to takeover readiness) was then conducted, revealing that although takeover event, SCL, and HR had slightly higher correlations with the maximum acceleration and reaction time, none of them dominated the takeover readiness. In addition, the analysis of the data across different participants was conducted, which emphasized the importance of considering standardization or normalization of the data when they were further used as input features for estimating takeover readiness. Overall, the results presented in this paper offer profound insights into the patterns of physiological data changes during takeover periods. These findings can be used as benchmarks for utilizing these variables as indicators of takeover preparedness and performance in future research endeavors.

Independent, additive and interactive effects of acute normobaric hypoxia and cold on submaximal and maximal endurance exercise.

To evaluate the independent and combined effects of hypoxia (FiO2 = 13.5%) and cold (-20°C) on physiological and perceptual responses to endurance exercise. 14 trained male subjects ( O2max: 64 ± 5mL/kg/min) randomly performed a discontinuous maximal incremental test to exhaustion on a motorized treadmill under four environmental conditions: Normothermic-Normoxia (N), Normothermic-Hypoxia (H), Cold-Normoxia (C) and Cold-Hypoxia (CH). Performance and physiological and perceptual responses throughout exercise were evaluated. Maximal WorkLoad (WL) and WL at lactate threshold (LT) were reduced in C (-2.3% and -3.5%) and H (-18.0% and -21.7%) compared to N, with no interactive (p = 0.25 and 0.81) but additive effect in CH (-21.5% and -24.6%). Similarly, HRmax and Vemax were reduced in C (-3.2% and -14.6%) and H (-5.0% and -7%), showing additive effects in CH (-7.7% and -16.6%). At LT, additive effect of C (-2.8%) and H (-3.8%) on HR reduction in CH (-5.7%) was maintained, whereas an interactive effect (p = 0.007) of the two stressors combined was noted on Ve (C: -3.1%, H: + 5.5%, CH: -10.9%). [La] curve shifted on the left in CH, displaying an interaction effect between the 2 stressors on this parameter. Finally, RPE at LT was exclusively reduced by hypoxia (p < 0.001), whereas TSmax is synergistically reduced by cold and hypoxia (interaction p = 0.047). If compared to single stress exposure, exercise performance and physiological and perceptual variables undergo additive or synergistic effects when cold and hypoxia are combined. These results provide new insight into human physiological responses to extreme environments.

Social Allostasis Regulation by Robots

Social allostasis, the process by which social interactions dynamically regulate psychophysiological states (e.g., emotions), is attracting attention. Social allostasis can significantly impact people's mental and physical wellbeing. However, adaptive social relationships are not necessarily available to all people. The use of robots is expected to solve this problem. In this paper, we present three studies of our group that prove the influence of social interactions with robots on human psychophysiological states. Our results showed that robots could amplify human subjective and physiological emotional responses through conversation, touch, and television co-viewing experiences. These results suggest that robots may be helpful for adaptive social allostasis regulation.

Thermal sensation and physiological responses in non-uniform bathing thermal environment: A comparative study on 25-, 52-, and 71-year-old participants

A non-uniform thermal environment significantly affects human physiological responses and even harms health. Specifically, a non-uniform bathing thermal environment is particularly deadly for older adults. Although each body part's arterial blood flow changes in the bathing thermal environment, little research has been conducted on the physiological responses of participants of different ages. Herein, we conducted a series of bathing experiments on three healthy participants aged 25, 52, and 71. The aim of these experiments to elucidate and analyze the thermal sensations and physiological responses of the participants in a non-uniform bathing thermal environment (i.e., the upper body was exposed to air, whereas the lower body was immersed in hot bathwater). We found that the non-uniform thermal environment greatly influenced a variety of physiological parameters and increased the participants' heart rates and blood flow. The youngest participant (i.e., the 25-year-old) and oldest participant (i.e., the 71-year-old) had the fastest and slowest perception of thermal sensation, respectively. The physiological responses changed significantly with the perception of thermal sensation change for the three participants. Unlike the other two participants, the oldest participant had decreased blood pressure and slowly increased thermal sensation. In addition, the oldest participant in a short bathing time had minor thermal health risks than younger participants due to exhibiting the slowest thermal response. However, older adults may experience greater thermal health risks due to their relatively slow thermal response in long-time and high-temperature bathing environments.