A simplified thermoregulation model of the human body in warm conditions

Exploring Thermal Dynamics in Wound Healing: The Impact of Temperature and Microenvironment

Exploring the critical role of thermal dynamics in wound healing, this manuscript navigates through the complex biological responses initiated upon wound infliction and how temperature variations influence the healing trajectory. Integrating biothermal physics, clinical medicine, and biomedical engineering, it highlights the significance of thermal management in wound care, emphasizing the wound microenvironment's division into internal and external domains and their collaborative impact on tissue repair. Innovations in real-time wound temperature monitoring, especially through intelligent wireless sensor dressings, are spotlighted as transformative, enabling precise wound condition management. The text underscores the necessity for further research to elucidate thermal regulation's molecular and cellular mechanisms on healing processes. It advocates for standardized protocols for localized heating treatments, integrating them into personalized wound care strategies to enhance therapeutic outcomes, improve patient well-being, and achieve cost-effective healthcare practices. This work presents a forward-looking perspective on refining wound management through sophisticated, evidence-based interventions, emphasizing the interplay between thermal dynamics and wound healing.

A thermoregulation model based on the physical and physiological characteristics of Chinese elderly

Given the increasing aging population and rising living standards in China, developing an accurate and straightforward thermoregulation model for the elderly has become increasingly essential. To address this need, an existing one-segment four-node thermoregulation model for the young was selected as the base model. This study developed the base model considering age-related physical and physiological changes to predict mean skin temperatures of the elderly. Measured data for model optimization were collected from 24 representative healthy Chinese elderly individuals (average age: 67 years). The subjects underwent temperature step changes between neutral and warm conditions with a temperature range of 25-34 °C. The model's demographic representation was first validated by comparing the subjects' physical characteristics with Chinese census data. Secondly, sensitivity analysis was performed to investigate the influences of passive system parameters on skin and core temperatures, and adjustments were implemented using measurement or literature data specific to the Chinese elderly. Thirdly, the active system was modified by resetting the body temperature set points. The active parameters to control thermoregulation activities were further optimized using the TPE (Tree-structured Parzen Estimator) hyperparameter tuning method. The model's accuracy was further verified using independent experimental data for a temperature range of 18-34 °C for Chinese elderly. By comprehensively considering age-induced thermal response changes, the proposed model has potential applications in designing and optimizing thermal management systems in buildings, as well as informing energy-efficient strategies tailored to the specific needs of the Chinese elderly population.

Homeostatic model of human thermoregulation with bi-stability

All homoiothermic organisms are capable of maintaining a stable body temperature using various negative feedback mechanisms. However, current models cannot satisfactorily describe the thermal adaptation of homoiothermic living systems in a physiologically meaningful way. Previously, we introduced stress entropic load, a novel variable designed to quantify adaptation costs, i.e. the stress of the organism, using a thermodynamic approach. In this study, we use stress entropic load as a starting point for the construction of a novel dynamical model of human thermoregulation. This model exhibits bi-stable mechanisms, a physiologically plausible features which has thus far not been demonstrated using a mathematical model. This finding allows us to predict critical points at which a living system, in this case a human body, may proceed towards two stabilities, only one of which is compatible with being alive. In the future, this may allow us to quantify not only the direction but rather the extent of therapeutic intervention in critical care patients.

Environmental heat-related health symptoms among community in a tropical city

Due to the changing climate, more frequent and prolonged heatwaves are expected to have a catastrophic consequence on urban human settlement. In tropical cities such as Kuala Lumpur (KL), the quality of the urban environment is made worse by urban heat island (UHI) phenomena due to poor urban planning practices. The prolonged exposure to urban heat is hypothesized to influence human health and well-being, especially in tropical urban areas with high population density. Therefore, a study was conducted to understand the association of urban heat stress with physical, psychosomatic and psychological (PPP) health symptoms within a tropical urban setting. Continuous urban microclimate monitoring is conducted using an automated weather station to define the level of heat stress in the study area expressed as Physiological Equivalent Temperature (PET). A cross-sectional approach is used to identify heat-related health symptoms experienced by the urban population. Through exploratory factor analysis, a total of 38 PPP health symptoms are reduced into 8 heat-related health clusters which are sensory organ pain, heat-related illnesses, cardiopulmonary, pain, fatigue, anxiety, somatization, and depression-related symptoms. Heat stress was found to significantly affect psychosomatic pain (p = 0.016) as well as psychological anxiety (p = 0.022) and somatization (p = 0.041) related symptoms. Other health clusters were not significantly associated with heat stress. More studies are needed to unravel the influence of confounding factors and the long-term impact of urban heat on the health and well-being of the urban population in a tropical city.

Models and Indicators to Assess Thermal Sensation Under Steady-state and Transient Conditions

The assessment of thermal sensation is the first stage of many studies aimed at addressing thermal comfort and at establishing the related criteria used in indoor and outdoor environments. The study of thermal sensation requires suitable modelling of the human body, taking into account the factors that affect the physiological and psychological reactions that occur under different environmental conditions. These aspects are becoming more and more relevant in the present context in which thermal sensation and thermal comfort are represented as objectives or constraints in a wider range of problems referring to the living environment. This paper first considers the models of the human body used in steady-state and transient conditions. Starting from the conceptual formulations of the heat balance equations, this paper follows the evolution occurred during the years to refine the models. This evolution is also marked by the availability of increasingly higher computational capability that enabled the researchers developing transient models with a growing level of detail and accuracy, and by the validation of the models through experimental studies that exploit advanced technologies. The paper then provides an overview of the indicators used to characterise the local and overall thermal sensation, indicating the relations with local and overall thermal comfort.

Developing a new individualized 3-node model for evaluating the effects of personal factors on thermal sensation

Individual differences, such as weight, height, gender, age, and Basal Metabolic Rate (BMR), between human subjects can significantly affect body thermoregulatory mechanisms. Therefore, application of common population-based thermal comfort models cannot provide accurate results for an individual's thermal sensation. Based on the standard thermal models, including those of Fanger and Gagge, individual parameters are not considered in the evaluation of thermal sensations. Thus, these simplified standard models have some limitations under varied individual conditions. In this study, a new individualized thermal comfort model is presented on the basis of a simplified 3-node model. This model was developed by regarding the effects of individual characteristics, such as age, gender, Body Mass Index (BMI), and BMR on the thermal sensations of the bare and clothed parts of the body. A good agreement was found in the current model, which was verified based on the experimental data. In conclusion, the results indicated that the mean error in the prediction of skin temperature decreased from 1.2°C to 0.4°C when using the new individual model instead of a non-individualized 3-node model.