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Purpose: The current study aimed to determine the effect of a synthetic-grass sport surface on core body temperature, skin temperature, heart rate, thermal sensation, thermal comfort, and rating of perceived exertion (RPE) during intermittent exercise in hot conditions. Methods: Using a randomized crossover design, 13 trained/developmental team-sport athletes completed two 50-minute standardized intermittent running protocols on a synthetic and a natural-grass surface, on separate days (control-condition air temperature 32.6 °C [1.3 °C], relative humidity 43.2% [5.3%]). Results: Final skin temperature was significantly higher on synthetic compared with natural grass at the calf (40.1 °C [2.5 °C] vs 33.4 °C [0.6 °C]; P <.001), shoulder (36.6 °C [1.7 °C] vs 33.7 °C [0.7 °C]; P <.001), and chest (33.2 °C [1.1 °C] vs 31.8 °C [1.2 °C]; P =.02). Thermal sensation (median: 2.3; interquartile range [0.5] vs 2.2 [0.5], P =.03) and sweat rate (1.5 [0.4] L·h−1 vs 1.2 [0.3] L·h−1; P =.02) were also significantly higher on synthetic grass. While final core body temperature was significantly higher on the natural than synthetic grass (38.4 °C [0.3 °C] vs 38.2 °C [0.4 °C]), there were no significant differences in delta core temperature, as well as heart rate, thermal comfort, or RPE. Conclusions: Higher skin temperatures, thermal sensation, and sweat rates suggest that exercising on synthetic grass in hot conditions may increase some markers of heat strain during exercise. However, delta core body temperature, heart rate, thermal comfort, and RPE remained unaffected. [ABSTRACT FROM AUTHOR]

Purpose: Open-water swimmers need to train with wetsuits to get familiar with them; however, body core temperature (Tcore) kinetics when using wetsuits in swimming-pool training remains unclear. The present study assessed the effects of wetsuit use in pool training on Tcore, subjective perceptions, and swimming performance to obtain suggestions for wearing wetsuits in training situations. Methods: Four elite/international-level Japanese swimmers (2 female, age 24 [1] y) completed two 10-km trials with (WS) and without wetsuit (SS) in the swimming pool (Tw: 29.0 °C). During the trial, swimmers were allowed to remove their wetsuit if they could no longer tolerate the heat. Tcore was continuously recorded via ingestible temperature sensors. Swimming speed was estimated from every 100-m lap time. Results:Tcore increased by distance in both trials in all swimmers. Tcore when swimmers removed their wetsuit in the WS (distance: 3800 [245] m, time: 2744 [247] s) was higher than that at the same distance in the SS in all swimmers. Rating of perceived exertion was higher in the SS than the WS, and swimming speed was slower in the WS than the SS in all swimmers. Conclusion: Wetsuit use during pool training increases Tcore and decreases swimming performance. Although wearing wetsuits in training situations is important for familiarization, for the safety of the swimmers, it is recommended that they remove their wetsuit if they feel too hot. [ABSTRACT FROM AUTHOR]

Purpose: Menthol mouth swills can improve endurance performance in the heat, which is attributed to attenuations in nonthermally derived thermal sensation (TS) and perception of effort. However, research in elite team-sport athletes is absent. Therefore, this study investigated the performance and TS responses to a 0.1% menthol mouth rinse (MR) or placebo (PLA) among elite male rugby union players. Method: Twenty-seven (15 Forwards and 12 Backs) elite male Super Rugby players completed two 3-minute 15-a-side rugby-specific conditioning blocks, with MR or PLA provided at the start of training (baseline), at the start of each 3-minute block (swill 1 [S1] and swill 2 [S2]), and at the end of training (swill 3 [S3]). TS was assessed using the American Society of Heating, Refrigerating and Air-Conditioning Engineers 9-point Analog Sensation Scale after each swill and at baseline (preconditioning block). Acceptability was measured after baseline swill and S3 using a 5-question Likert scale. Physical performance was measured throughout training using global positioning system metrics. Results: MR attenuated TS from baseline to S1 (P =.003, SD = 1.01) and S2 (P =.002, SD = 1.09) in Forwards only, compared with PLA. Acceptability was higher only for Forwards in MR versus PLA at baseline (P =.003, SD = 1.3) and S3 (P =.004, SD = 0.75). MR had no effect on physical performance metrics (P >.05). Conclusion: MR attenuated the rise in TS with higher acceptability at S1 and S3 (in Forwards only) with no effect on selected physical performance metrics. Longer-duration exercise (eg, a match) in hot–humid conditions eliciting markedly increased body temperatures could theoretically allow favorable changes in TS to enhance performance—these postulations warrant experimental investigation. [ABSTRACT FROM AUTHOR]

The model for predicting thermal comfort conditions established by Fanger remains widely used in scientific work, as a default means of in situ measurements. However, the use of Fanger data leads to dissatisfaction among users of air-conditioned buildings in humid tropical areas. This conclusion emerges from the work of Kemajou and al. (Cameroon) and Olissan and al. (Benin) in 2012, after survey studies on the judgments of thermal sensations of people occupying various air-conditioned spaces. This article develops a correction model for the Fanger model, by coupling the latter to models for predicting skin temperature and heat loss by evaporation of sweat through the skin, as well as to the skin thermal sensitivity of people active in a humid tropical climate. The model thus determined shows that the predicted optimal comfort temperatures are located in the range of 26.1 °C to 27.5 °C and better meets the expectations of the populations in this region. The respective differences with the investigations of Kemajou and al. and those of Olissan and al. are 0.40 °C and 0.55 °C. It also appears that the comfort humidity range is 30% to 80%, apart from any other safety measures. [ABSTRACT FROM AUTHOR]

Abstract The model for predicting thermal comfort conditions established by Fanger remains widely used in scientific work, as a default means of in situ measurements. However, the use of Fanger data leads to dissatisfaction among users of air-conditioned buildings in humid tropical areas. This conclusion emerges from the work of Kemajou and al. (Cameroon) and Olissan and al. (Benin) in 2012, after survey studies on the judgments of thermal sensations of people occupying various air-conditioned spaces. This article develops a correction model for the Fanger model, by coupling the latter to models for predicting skin temperature and heat loss by evaporation of sweat through the skin, as well as to the skin thermal sensitivity of people active in a humid tropical climate. The model thus determined shows that the predicted optimal comfort temperatures are located in the range of 26.1 °C to 27.5 °C and better meets the expectations of the populations in this region. The respective differences with the investigations of Kemajou and al. and those of Olissan and al. are 0.40 °C and 0.55 °C. It also appears that the comfort humidity range is 30% to 80%, apart from any other safety measures.

At present, air handling units are usually used indoors to improve the indoor environment quality. However, while introducing fresh air to improve air quality, air velocity has a certain impact on the occupants' thermal comfort. Therefore, it is necessary to explore the optimization of air-fluid-body interaction dynamics. In this study, the indoor air flow was changed by changing the opening and closing degree of the blower, and the thermal manikin is introduced to objectively evaluate the human thermal comfort under different air velocities. The main experimental results show that the air change rate increases with the increase of the opening and closing degree of the blower considering an ACH (air changes per hour) range between 3.8 and 10. For a better prediction, a linear correlation with a coefficient of 0.995 is proposed. As the blower's opening is adjusted to 20%, 25%, 30%, 35%, and 40%, the air velocity sensor positioned directly beneath the air inlet records average velocities of 0.19, 0.20, 0.21, 0.28, and 0.34 m/s over four hours, respectively. Observations on thermal comfort and the average sensation experienced by individuals indicate an initial increase followed by a decline when the blower's operation begins, with optimal conditions achieved at a 35% opening. These findings offer valuable insights for future indoor air ventilation and heat transfer design strategies. [ABSTRACT FROM AUTHOR]

The air conditioning (A/C) of cabins allows for customized control, but manual adjustments may distract drivers, as well as result in energy inefficiency. Several existing thermal sensation models require complex inputs, which are challenging to gather whilst driving. To address this issue, this study developed a non-contact thermal sensation model for cabin occupants based on thermal imaging sensor. To collect actual data used for modeling, an outdoor subject experiment was conducted. In this study, initial training was conducted to compare the performance of six algorithms in building the model, with random forests algorithm showing the best performance. Besides, this study employed the recursive feature elimination (RFE) method with cross-validation algorithm for identifying the key features. In the end, the model was retrained using the selected features. The model that incorporated both environmental parameters and facial-temperature features demonstrated the best performance, with an R2 of 0.659 on the test set. Eliminating the hard-to-measure windshield surface temperature resulted in a slight reduction in accuracy, yielding an R2 of 0.651. To verify the generalizability of the model, this study further conducted independent validation experiments. The selected model, which exhibited a mean absolute error (MAE) of less than 0.4 in thermal sensation units, was proven to be highly applicable. The results can offer new solutions for automatic control of cabin A/C. [ABSTRACT FROM AUTHOR]

This study focuses on improving human thermal comfort in a high-temperature outdoor environment using vests with a radiative cooling coating. The effects of coating thickness on the radiative cooling performance were first evaluated, and an optimal thickness of 160 μm was achieved. Then, six subjects were recruited to evaluate the thermal comfort in two scenarios: wearing the vest with radiative cooling coatings, and wearing the standard vest. Compared with the standard vest, the coated vest decreases the maximum temperature at the vest inner surface and the outer surface by 5.54 °C and 4.37 °C, respectively. The results show that thermal comfort is improved by wearing radiative cooling vests. With an increase of wet bulb globe temperature (WBGT), the improving effects tend to decline. A significant improvement in human thermal comfort is observed at a WBGT of 26 °C. Specifically, the percentage of thermal sensation vote (TSV) wearing the cooling vest in the range of 0 to 1 increases from 29.2% to 66.7% compared with that of the untreated vest. At the same time, the average value of thermal comfort vote (TCV) increases from −0.5 to 0.2. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Arquitectura (1657-0308) is the property of Universidad Catolica de Columbia, Facultad de Arquitectura and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Maintaining regular physical exercise is essential for maintaining good health. In China, fitness centres are thriving, and the cleanliness of the exercise environment has become increasingly important. This study investigated the thermal response and indoor air environment of fitness personnel in various areas of a fitness centre using subjective evaluation and on-site air environment measurements. The findings revealed that the indoor air environment in different exercise areas of the fitness centre varied spatially, which can lead to discomfort amongst fitness personnel during exercise. Overall, the thermal sensation in different areas of the fitness centre was found consistently too hot. Temperature and humidity have the greatest impact on the thermal sensation of individuals in different areas, while indoor air pollutants have a minimal effect. The intensity and duration of exercise can also influence the body's heat sensation and pollutant inhalation dose. The body's heat balance mechanism can affect subjective evaluations. This study proposes three strategies for optimizing the indoor environment of fitness centres through principal component analysis. This paper provides data and a methodological framework for the development of specifications supporting the design, operation and management of the environment in fitness centres. [ABSTRACT FROM AUTHOR]

Copyright of FME Transactions is the property of University of Belgrade, Faculty of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives Subjects and Methods Results Conclusions Few studies used thermal quantitative sensory testing to assess the effects of repeated capsaicin gel administration in the oral cavity. This study aimed to investigate thermal sensory and pain thresholds before and after repeated capsaicin gel administration.Ten healthy females (22 ± 2 years) applied a capsaicin gel on the gingival mucosa twice daily for 14 days, and heat pain threshold, warm detection threshold, cold pain threshold, and cold detection threshold were assessed on the oral mucosa. Measurements were performed before and after the 14 days and were compared to a control sample (n = 10, all females, 23 ± 3 years).Capsaicin increased heat pain threshold in the anterior maxilla by 2.9°C (95% CI: 1.6–4.2) (p < 0.001) and in the anterior mandible by 2.2°C (95% CI: 1.0–3.4) (p = 0.001), similar to warm detection threshold that increased by Δ1.1°C (95% CI: 0.3–1.9) (p = 0.009). No significant changes were found in the controls.These findings encourage the use of thermal quantitative sensory testing in the oral cavity to assess thermal sensation, which might be useful for assessing the effects of therapies aimed at reducing pain. [ABSTRACT FROM AUTHOR]

Introduction: Methyl salicylate, the main compound of wintergreen oil, is widely used in topical applications. However, its vascular and thermosensory effects are not fully understood. The primary aim was to investigate the effects of topical methyl salicylate on skin temperature (Tskin), skin microcirculation (MCskin) and muscle oxygen saturation (SmO2) compared to a placebo gel. The secondary aim was to assess thermosensory responses (thermal sensation, thermal comfort) and to explore to which extent these sensations correspond to the physiological responses over time. Methods: 21 healthy women (22.2 ± 2.9 years) participated in this single-blind, randomized controlled trial. Custom-made natural wintergreen oil (12.9%), containing methyl salicylate (>99%) and a placebo gel, 1 g each, were applied simultaneously to two paravertebral skin areas (5 cm × 10 cm, Th4-Th7). Tskin (infrared thermal imaging), MCskin (laser speckle contrast imaging) and SmO2 (deep tissue oxygenation monitoring) and thermosensation (Likert scales) were assessed at baseline (BL) and at 5-min intervals during a 45 min post-application period (T0-T45). Results: Both gels caused an initial decrease in Tskin, with Tskin(min) at T5 for both methyl salicylate (BL-T5: Δ-3.36°C) and placebo (BL-T5: Δ-3.90°C), followed by a gradual increase (p < .001). Methyl salicylate gel resulted in significantly higher Tskin than placebo between T5 and T40 (p < .05). For methyl salicylate, MCskin increased, with MCskin(max) at T5 (BL-T5: Δ88.7%). For placebo, MCskin decreased (BL-T5: Δ-17.5%), with significantly lower values compared to methyl salicylate between T0 and T45 (p < .05). Both gels had minimal effects on SmO2, with no significant differences between methyl salicylate and placebo (p > .05). Thermal sensation responses to topical methyl salicylate ranged from "cool" to "hot", with more intense sensations reported at T5. Discussion: The findings indicate that topical methyl salicylate induces shortterm cutaneous vasodilation, but it may not enhance skeletal muscle blood flow. This study highlights the complex sensory responses to its application, which may be based on the short-term modulation of thermosensitive transient receptor potential channels. [ABSTRACT FROM AUTHOR]

Escalating global climate change and the intensification of urban heatwaves have led to an increase in summer air conditioning cooling energy consumption. This phenomenon is particularly critical in tropical regions, as it may trigger an energy crisis. The rational setting of indoor thermal design parameters can help conserve energy to the maximum extent while ensuring thermal comfort for occupants. This study selected Haikou City, a unique tropical city in China, as the research location. Indoor environment measurements and a questionnaire survey were conducted with participants, and the outdoor thermal environment sensitivity, population attributes and differences in thermal sensation, thermal neutral temperature, and comfort range were calculated and analyzed. The following results were obtained. Based on the overall population, long-term residence, and temporary residence classification, the indoor thermal comfort needs of residents in tropical cities in Haikou were effectively identified. The actual thermal neutral temperature of the overall population is 25.7 °C, and 90% of the acceptable thermal comfort temperature range is 23.2 °C–28.0 °C. The actual thermal neutral temperature of the regular residents is 27.3 °C, and 90% of the acceptable thermal comfort temperature range is 23.3 °C–31.4 °C. The actual thermal neutral temperature of the temporary population is 25.5 °C, and 90% of the acceptable thermal comfort temperature range is 23.0 °C–28.0 °C. These research results have an important reference value for improving the setting of the temperature of air conditioning in tropical areas in summer and further reducing energy consumption, which is conducive to sustainable development. [ABSTRACT FROM AUTHOR]

This study aims to evaluate agreement among subjective thermal comfort, thermal sensation, thermal perception, and thermal tolerance indices, according to pedestrians in downtown Santa Maria, southern Brazil, which has a humid subtropical climate (Cfa). Between August 2015 and July 2016 (three periods), 1728 questionnaires were applied. Evaluation of the dependence of statistical variables was based on gender and age, at three periods of time: August 2015 (864 respondents), January 2016 (432 respondents), and July 2016 (432 respondents). Statistical evaluation was based on Pearson's chi-square test using RStudio software, and a significance level (α) of 5% for thermal comfort, thermal sensation, thermal preference, and thermal tolerance was used. Results indicated that age and gender affect the relationship between the variables. Thermal comfort and thermal tolerance presented the best correlation and coherence, regardless of age or gender. This study contributes to knowledge on the local microclimate and can contribute to urban planning to implement strategies that improve pedestrians' thermal comfort. [ABSTRACT FROM AUTHOR]

The application of 28 GHz millimeter-wave is prevalent owing to the global spread of fifth-generation wireless communication systems. Its thermal effect is a dominant factor which potentially causes pain and tissue damage to the body parts exposed to the millimeter waves. However, the threshold of this thermal sensation, that is, the degree of change in skin temperature from the baseline at which the first subjective response to the thermal effects of the millimeter waves occurs, remains unclear. Here, we investigated the thermal sensation threshold and assessed its reliability when exposed to millimeter waves. Twenty healthy adults were exposed to 28 GHz millimeter-wave on their left middle fingertip at five levels of antenna input power: 0.2, 1.1, 1.6, 2.1, and 3.4 W (incident power density: 27--399 mW/cm2). This measurement session was repeated twice on the same day to evaluate the threshold reliability. The intraclass correlation coefficient (ICC) and Bland--Altman analysis were used as proxies for the relative and absolute reliability, respectively. The number of participants who perceived a sensation during the two sessions at each exposure level was also counted as the perception rate. Mean thermal sensation thresholds were within 0.9°C--1.0°C for the 126--399 mW/cm2 conditions, while that was 0.2°C for the 27 mW/cm2 condition. The ICCs for the threshold at 27 and 126 mW/cm2 were interpreted as poor and fair, respectively, while those at higher exposure levels were moderate to substantial. Apart from a proportional bias in the 191 mW/cm2 condition, there was no fixed bias. All participants perceived a thermal sensation at 399 mW/cm2 in both sessions, and the perception rate gradually decreased with lower exposure levels. Importantly, two-thirds of the participants answered that they felt a thermal sensation in both or one of the sessions at 27 mW/cm2, despite the low-temperature increase. These results suggest that the thermal sensation threshold is around 1.0°C, consistent across exposure levels, while its reliability increases with higher exposure levels. Furthermore, the perception of thermal sensation may be inherently ambiguous owing to the nature of human perception. [ABSTRACT FROM AUTHOR]

Existing research have explored thermal sensitivity under steady thermal conditions while how it changes with time is unknown. In this study, the arm and face were taken as examples to study dynamic characteristics of thermal sensitivity. The test spots were stimulated under thermally neutral ambient conditions to obtain skin temperature and thermal sensation at three levels (e.g. the micro-scale (1.54 cm2) spot, local body part and whole body) at intervals of 4 s. Results showed that in the first 4 s of stimuli, skin temperature change would reach 52% of the final variation. The overshooting rate of the arm thermal sensitivity was 1.6 and 1.8 times over the stable state for cooling and heating stimuli, and that of the face was 1.9 and 2.0 times. 95% of subjects on the arm and 85% on the face were more sensitive to cooling stimuli. The warmth sensitivities of different genders and body parts were shown to be significantly different, while the cold sensitivity of different body parts produced small differences. When stimulating one test spot, the ratio of thermal sensation at three levels was 15:4:1 on the arm and 16:3:1 on the face. These results can help to understand how the body responds to spatially ununiform and temporally unsteady thermal exposures. [ABSTRACT FROM AUTHOR]

When the human body experiences heat stress beyond the normal range, it may affect health and work efficiency to a certain extent. This study aimed to investigate the effectiveness of cold stimulation on Dazhui point (GV14), bilateral Xinshu points (B15), bilateral Danshu points (B19), and bilateral Quchi points (LI11) in the body to relieve heat strain in a high-temperature environment. The experiment results showed that the skin temperature (Tskin), tympanic temperature (Tty), heart rate (HR), the physiological strain index based on heart rate (PSIHR), thermal sensation (TS), and thermal comfort (TC) of the participants with acupoints cold stimulation were better than those without acupoints cold stimulation (p < 0.05). Tskin decreased by an average of 0.04 ± 0.46Ԩ. Tty decreased by an average of 0.08 ± 0.21Ԩ. The study concluded that cold stimulation at acupoints could reduce the heat strain and improve the thermal comfort of the human body.

This work demonstrates the development and effectiveness of a novel diagnostic device that uses virtual reality (VR) and micro-heating touch feedback to measure the size and temperature of lung tumors. This cutting-edge technology helps with the accurate diagnosis and localization of tumors by providing users with a warm sensation when they touch a 3D rendering of a tumor inside a VR environment. By integrating thermal feedback with immersive VR, we enhance the accuracy and intuitiveness of tumor detection, potentially contributing to better diagnostic results and enabling more efficient treatment planning. The integration of thermal feedback not only enhances the realism of the virtual interaction but also makes it easier for the user to locate tumors precisely based on temperature changes. This new method offers a more thorough and interactive way to assess the identification and localization of lung cancers, which is a significant improvement in medical diagnostics. Rapid identification and detection are crucial as they can significantly enhance survival probabilities, especially since early detection is often challenging. This paper presents the development of a novel device for lung tumor analysis, employing VR and thermal technologies to provide thermal touch feedback. At the core of this device is the innovative use of microheater-based technology, integrating new techniques for thermal sensation. Through the use of a VR interface, our microheater device was examined. Users were able to interact with 3D-rendered lung tumors and experience a heat sensation that was different from the surrounding lung tissue. The MEMS microheater demonstrated a response time of approximately 16 seconds, significantly faster than the 200 seconds required by traditional Peltier devices. The preliminary results show that our microheater device offers optimal performances in terms of response time and allows low energy consumption (range of milliwatts), compared to the Peltier actuator. The results further demonstrate that our microheater’s optimized thermal touch feedback produces precise and safe temperatures for tumor detection.

Considering the percentage of dissatisfied due to local thermal sensation (PDLTSV), a vertical air temperature difference (ΔTd) threshold of about 3 °C was recommended in standards. However, some novel air distribution methods might create large positive (which means the head warmer than the feet, vice versa) or negative ΔTd, with no suitable proved criteria to be used. In this study, sixteen subjects were seated in a climatic box placed in a climate chamber to evaluate thermal sensation and percentage of dissatisfied with negative and positive ΔTd in different whole-body thermal conditions. Air temperatures were controlled independently at the upper and lower body parts, with 13 different air temperature sets combined with 22 °C, 25 °C, 28 °C, and 31 °C (i.e. -9 °C ≤ ΔTd ≤ 9 °C). Results showed that subjects were more thermally sensitive at the upper body and with positive ΔTd than at the lower body or with negative ΔTd. The 80% acceptable ΔTd range is about -8 to 7 °C in overall neutral (TSV = 0), -7 °C to 6 °C in slightly cool (TSV = -0.5) conditions, which is wider than -3 to 3 °C in slightly warm conditions (TSV = +0.5). By considering the factors of both TSV and ΔTd, a new overall percentage of dissatisfied index (OPDP) was proposed. Case studies show that the new OPDP index is more precise and suitable for the evaluations of different air distributions to predict overall percentage of dissatisfied in thermal environments with vertical air temperature difference.

Older adults are at greater risk of heat-related morbidity and mortality during heat waves, which is commonly linked to impaired thermoregulation. However, little is known about the influence of increasing age on the relation between thermal strain and perceptual responses during daylong heat exposure. We evaluated thermal and perceptual responses in 20 young (19-31 yr) and 39 older adults (20 with hypertension and/or type 2 diabetes; 61-78 yr) resting in the heat for 9 h (heat index: 37°C). Body core and mean skin temperature areas under the curve (AUC, hours 0-9) were assessed as indicators of cumulative thermal strain. Self-reported symptoms (68-item environmental symptoms questionnaire) and mood disturbance (40-item profile of mood states questionnaire) were assessed at end-heating (adjusted for prescores). Body core temperature AUC was 2.4℃·h [1.0, 3.7] higher in older relative to young adults (P < 0.001), whereas mean skin temperature AUC was not different (-0.5℃·h [-4.1, 3.2] P = 0.799). At end-heating, self-reported symptoms were not different between age groups (0.99-fold [0.80, 1.23], P = 0.923), with or without adjustment for body core or mean skin temperature AUC (both P > 0.824). Mood disturbance was 0.93-fold [0.88, 0.99] lower in older, relative to young adults (P = 0.031). Older adults with and without chronic health conditions experienced similar thermal strain, yet those with these conditions reported lower symptom scores and mood disturbance compared with young adults and their age-matched counterparts (all P < 0.026). Although older adults experienced heightened thermal strain during the 9-h heat exposure, they did not experience greater self-reported symptoms or mood disturbance relative to young adults. [ABSTRACT FROM AUTHOR]

Thermal sensation prediction models can help to evaluate complex thermal environments and guide the environment conditioning strategy. However, most existing models are established basing on the thermal status of the entire human body or local body parts, failing to reflect thermal sensation generating mechanism or micro-scale (centimeter-scale) thermal sensation. This study put forward a new thermal sensation predicting approach by coupling the skin heat transfer and the thermoreceptor impulse signals. The micro-scale thermal sensitivity data under steady stimuli were applied to bridging the objective heat transfer model and the subjective sensation model. The model contains a one-dimensional skin heat transfer equation and three sensation-generating equations: the thermoreceptor impulse equation, the psychosensory intensity equation, and the thermal sensation equation. The dimension of the skin heat transfer equation was determined through a skin temperature diffusion experiment, and the coefficients of the static/dynamic impulse in the thermoreceptor impulse equation and the thermal sensation equation were obtained through polynomial fitting using thermal sensitivity data. The validated mean absolute percentage error (MAPE) was 0.08 and 0.1 under cooling and heating stimuli, respectively. This new model can predict thermal sensation on the centimeter scale and be applied under different boundary conditions. In the future, the new model can be further developed by testing dynamic stimuli and other boundary conditions so that it can be applied to more complex thermal exposures. [ABSTRACT FROM AUTHOR]

Introduction: Thermal feedback technologies have been explored in human- computer interaction to provide secondary information and enhance the overall user experience. Unlike fast-response hapticmodalities such as vibration and force feedback, the human brain's processes associated with thermal feedback are not fully understood. Methods: In this study, we utilize electroencephalography (EEG) brain imaging to systematically examine the neural correlates associated with a wide range of thermal stimuli, including 9, 15, 32, and 42C, during active touch at the fingertip. A custom experimental setup is developed to provide thermal stimulation at the desirable temperature levels. A total of 30 participants are recruited to experience the four levels of thermal stimulation by actively touching a thermal stimulation unit with the index finger while recording brain activities via EEG. Time-frequency analysis and power spectral density (PSD) of the EEG data are utilized to analyze the delta, theta, alpha, beta, and gamma frequency bands. Results: The results show that the delta, theta, and alpha PSDs of 9 and 15C stimuli are significantly higher than the PSDs of 32 and 42C in the right frontal area during the early stage of the stimulation, from 282ms up to 1,108ms (One- way ANOVA test, Holm-Bonferroni correction, p < 0.05). No significant di [ABSTRACT FROM AUTHOR]

Thermoelectricity can assist in creating comfortable thermal environments through wearable solutions and local applications that keep the temperature comfortable around individuals. In the analysis of an indoor environment, thermal comfort depends on the global characteristics of the indoor volume and on the local thermal environment where the individuals develop their activity. This paper addresses the heat transfer mechanisms that refer to individuals, which operate in their working ambient when wearable thermoelectric solutions are used for enhancing heating or cooling within the local environment. After recalling the characteristics of the thermoelectric generators and illustrating the heat transfer mechanisms between the human body and the environment, the interactions between wearable thermoelectric generators and the human skin are discussed, considering the analytical representations of the thermal phenomena. The wearable solutions with thermoelectric generators for personal thermal management are then categorized by considering active and passive thermal management methods, natural and assisted heat exchange, autonomous and nonautonomous devices, and direct or indirect contact with the human body. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Refrigeration is the property of Journal of Refrigeration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

It is shown that changes in ambient temperature have a significant impact on human heart activity. People can suffer from cardiovascular disease because of cold or extreme temperatures. Based on the human heart rate variability index, the advantages of temperature drift thermal environments in indoor thermal comfort were explored. The relationship between subjective thermal evaluation, skin temperature and heart rate variability in humans were also analyzed. 16 Subjects underwent a half-hour temperature drift from the initial stable temperatures (24 ℃ or 18 ℃ ) in winter and finally warmed up back to the initial temperatures. Subjective thermal evaluations and skin temperatures were collected from the subjects and the electrogastrogram ECG signals were monitored throughout the experiment. Meanwhile, the LF/ HF values of heart rate variability were obtained by frequency domain analysis. The results show that the subjects' thermal comfort evaluation to the same temperature thermal environment in winter can be improved by the appropriate temperature drift. The effect of temperature drift on human thermal comfort can be characterized by LF/ HF values. The LF/ HF values of humans are significantly correlated with the mean skin temperature and thermal sensation in the winter thermal environment with temperature drift. [ABSTRACT FROM AUTHOR]

Abstract We investigated the effects of peripheral cooling using chemotherapy gloves and socks at three cooling temperatures on subjective perceptions. The hands and feet were cooled with 8, 11, and 14°C by water-perfused gloves or socks. Nine females participated in six experimental conditions: hands or feet cooling at 8, 11, and 14°C. The heat was extracted at 3.8, 5.4, and 7.7 kJ·min1 via the gloves and at 4.1, 6.0, and 9.0 kJ·min-1 via the socks. While the results showed that overall subjective perceptions did not differ among the three temperatures (~ 9.0 kJ·min-1), there were significant differences in local thermal comfort, pain sensation, and pain discomfort among the three cooling temperatures (P

Abstract Background We examined whether an aerobic exercise intervention in young women with cold sensitivity symptoms improves sleep quality and decreases cold complaints. Furthermore, we examined the association with increased foot skin temperature (Tsk) before falling asleep and decrease in sensitivity to cold in the brain. Methods We recruited 16 female adult volunteers who had cold sensitivity and were not engaged in daily exercise training, and they were divided into an exercise group (EXE) and a control group (CON). EXE was given a 2-week exercise intervention that consisted mainly of walking and jogging. Before and after the intervention, temperature sensation and body temperature parameters were measured just before bedtime; electroencephalogram measurements were taken during sleep; and subjective sleep surveys, including Oguri-Shirakawa-Azumi (OSA) sleep inventory (middle-aged and aged version) and visual analogue scale (VAS), were conducted immediately after waking up. All experiments were performed in the winter season. Results In EXE, overall and foot warmth and comfort increased (p

The metabolic rate (MET) is a fundamental parameter influencing thermal comfort. In this paper, the MET is obtained by indirect calorimetry to propose equations and related laws applicable to the environment at an altitude of 4 m, so as to enrich the research. Here, experiments with 30 healthy male subjects are conducted at sitting, 2, 4, and 6 km/h walking speeds in various ambient environments controlled by the climate chamber. The MET, thermal sensation vote (TSV), and heart rate (HR) were collected during the experiments. The results indicate that the ambient environments have little impact on MET, but it is obvious for HR. The linear relationship between walking speed, HR, and MET is fitted to be MET = 28.38 × Speed + 62.25 and MET = 3.67 × HR − 195.56. Moreover, the TSV and five kinds of predicted mean vote (PMV) calculated by various sources of MET are compared. For sitting activity, a slight difference from the MET could cause a significant difference in PMV, which leads to the PMV that may be above, below, or close to the TSV. For the 2 km/h walking activity, five kinds of PMV are close to TSV. However, for the 4 km/h walking activity, PMV is always higher than TSV. These findings are significant in elucidating the relationship between MET and thermal comfort.

This study focuses on improving human thermal comfort in a high-temperature outdoor environment using vests with a radiative cooling coating. The effects of coating thickness on the radiative cooling performance were first evaluated, and an optimal thickness of 160 μm was achieved. Then, six subjects were recruited to evaluate the thermal comfort in two scenarios: wearing the vest with radiative cooling coatings, and wearing the standard vest. Compared with the standard vest, the coated vest decreases the maximum temperature at the vest inner surface and the outer surface by 5.54 °C and 4.37 °C, respectively. The results show that thermal comfort is improved by wearing radiative cooling vests. With an increase of wet bulb globe temperature (WBGT), the improving effects tend to decline. A significant improvement in human thermal comfort is observed at a WBGT of 26 °C. Specifically, the percentage of thermal sensation vote (TSV) wearing the cooling vest in the range of 0 to 1 increases from 29.2% to 66.7% compared with that of the untreated vest. At the same time, the average value of thermal comfort vote (TCV) increases from −0.5 to 0.2.

Background: Dementia involves a neuronal loss in the primary somatosensory cortex of the parietal lobe, causing dementia patients to perceive pain stimuli hardly. The function of temperature sensation declines. Studies measuring brain blood volume using near-infrared light have reported that patients suffering from dementia have less activation than healthy elderly people. However, the majority of these studies used tests related to cognitive function and the frontal lobe, and few have examined thermal sensation.Objective: The present study aimed to investigate the effect of cold and warm stimulation on cerebral blood volume in elderly and young subjects.Material and Methods: This observational study measured changes in oxygenated hemoglobin concentrations in the frontal cortex during cold and warm stimulation in elderly and young subjects using a near-infrared light device. The mean and standard deviation of the change in oxygenated hemoglobin concentration before and after cold and warm stimulation, as well as the center-of-gravity values, were compared between the young and the elderly.Results: During warm stimulation, the younger subjects showed an increase in blood oxygenated hemoglobin levels; however, the difference was not significant. For the elderly, no change was observed during the task. The center of gravity values was lower in the young compared to the elderly which was similar to the reaction threshold. No significant changes were observed during cold stimulation. Conclusion: Thermal sensation thresholds were impaired in the elderly compared to the young; however, cerebral blood volume changes were unclear.

The thermal comfort of frail people has to be considered carefully, mainly because of the high thermal sensitivity of this population and the negative influences that unsatisfactory thermal conditions have on their health. Most existing thermal comfort works have been conducted under steady-state, uniform thermal environments, with far fewer being performed in dynamic and non-uniform thermal environments, and even less for frail people. This study aimed at assessing the thermal responses of frail people under transient and non-uniform thermal environments, using a thermal manikin and a climatic test cell. Thermal responses were investigated and discussed in both genders. The analysis of variance showed a significant difference in thermal comfort and thermal sensation between females and males over time, under hot exposure. Under cold exposure, results showed a significant difference in thermal sensation between females and males over time, but no significant difference was observed in term of thermal comfort. Analysis revealed also significant differences in the dynamic thermal sensation between the sexes under cold exposure, while results confirmed that there is no significant difference in the dynamic thermal sensation between sexes under hot exposure.

IntroductionThermal feedback technologies have been explored in human-computer interaction to provide secondary information and enhance the overall user experience. Unlike fast-response haptic modalities such as vibration and force feedback, the human brain's processes associated with thermal feedback are not fully understood.MethodsIn this study, we utilize electroencephalography (EEG) brain imaging to systematically examine the neural correlates associated with a wide range of thermal stimuli, including 9, 15, 32, and 42°C, during active touch at the fingertip. A custom experimental setup is developed to provide thermal stimulation at the desirable temperature levels. A total of 30 participants are recruited to experience the four levels of thermal stimulation by actively touching a thermal stimulation unit with the index finger while recording brain activities via EEG. Time-frequency analysis and power spectral density (PSD) of the EEG data are utilized to analyze the delta, theta, alpha, beta, and gamma frequency bands.ResultsThe results show that the delta, theta, and alpha PSDs of 9 and 15°C stimuli are significantly higher than the PSDs of 32 and 42°C in the right frontal area during the early stage of the stimulation, from 282 ms up to 1,108 ms (One-way ANOVA test, Holm-Bonferroni correction, p < 0.05). No significant differences in PSDs are found between 9 and 15°C thermal stimuli or between 32 and 42°C thermal stimuli.DiscussionThe findings of this study inform the development of thermal feedback system in human-computer interaction.

The clothing color could always produce different human heat transfer and thermal sensation under solar radiation. And this issue has already been scrutinized by a few studies in outdoor environment. As the natural lighting is becoming common in buildings, e.g. the large curtain walls in high-rise buildings, the direct solar radiation could also affect the indoor occupants. Consequently, effects of the clothing color on the human body could not be ignored. Unfortunately, very limited studies have been reported in this field. In order to acquire the contribution of the clothing color to the heat transfer and thermal sensation of the indoor occupants, experimental study was conducted in this paper. Firstly, considering the non-uniformity of direct solar radiation on the indoor occupants, the equations that were used to calculate the solar heat gain of different body segments and the clothing surface temperature were revised, respectively. Thereafter, an experimental study was conducted in a climate chamber in winter. Participants wore cloth with different colors when exposed to different solar radiation intensities, during which the mean skin temperature, heat transfer, and subjective evaluations were acquired. Results showed that the dark clothing led to the reduced total heat loss by 4.52%, compared with that of the light clothing, at the solar radiation intensity of 200 W/m2. And the mean thermal sensation vote (TSV) under dark clothing was 0.65 higher than that under the light clothing. Meanwhile, at the solar radiation of 400 W/m2, the total heat loss under dark clothing was 14.17% lower than that under the light clothing, and the mean TSV under the dark clothing was found to be 0.25 higher that under light clothing condition. The results implied that wearing the dark clothing could benefit the improvement of the indoor human thermal comfort at low solar radiation in winter. These findings could provide a few useful references for studies on indoor thermal comfort under the solar radiation.

Global warming has increased the cooling energy consumption for the operation of built heritages, especially for industrial heritage which suffers from thermal performance deficiencies and are facing the dilemma of functional conversion. In order to satisfy the thermal comfort of users while preserving the value of the heritage, it is necessary to monitor the indoor environment and to analyze its impacts on thermal comfort of human beings. In present study, a cotton textile factory heritage located in Qingdao, Shandong Province, China, was selected, where a long-term investigation of indoor environmental conditions as well as thermal comfort were conducted over a period of 78 days. What's more, the temperature distribution in space field was analyzed by applying CFD simulation. The obtained results show that: i) the indoor temperature fluctuates greatly and the relative humidity as well as CO2 concentration maintain at a high level, failing to provide a satisfactory indoor environment; ii) For most of the time, users report complaints about thermal discomfort, with the hottest mean thermal sensation vote (TSV) being close to warm (1.76) and the worst mean thermal comfort vote (TCV) reaching uncomfortable (−1.60); iii) The deviation between PMV and TSV demonstrates the limitations of the Fanger's model when applied in industrial heritage, and the thermal comfort perception of users are influenced by indoor humidity, CO2 concentration and outdoor temperature. The performed analyses suggest that the indoor thermal environment of industrial heritage fails to keep pace with the transformation of its nature and function. These findings will provide basic research for the retrofitting of industrial heritage.

We investigated the effects of peripheral cooling using chemotherapy gloves and socks at three cooling temperatures on subjective perceptions. The hands and feet were cooled with 8, 11, and 14°C by water-perfused gloves or socks. Nine females participated in six experimental conditions: hands or feet cooling at 8, 11, and 14°C. The heat was extracted at 3.8, 5.4, and 7.7 kJ·min1 via the gloves and at 4.1, 6.0, and 9.0 kJ·min-1 via the socks. While the results showed that overall subjective perceptions did not differ among the three temperatures (~ 9.0 kJ·min-1), there were significant differences in local thermal comfort, pain sensation, and pain discomfort among the three cooling temperatures (P < 0.05). When cooling the hands or feet at 8, 11 or 14°C, subjects felt 'cold' or 'cool', on average, at the end of 60-min cooling with no significant differences among the three temperatures, whereas subjects felt more uncomfortable at 8°C than 14°C for cooling either the hands or feet (P < 0.05). Subjects felt more pain at 8°C than 14°C cooling for both hands and feet. These results indicate that the 8°C cooling for 60 min might cause uncomfortable pain sensation, especially for cold-vulnerable individuals. We recommend 1) a cooling bout of less than 60 min, 2) a cooling temperature higher than 8oC when cooling the hands or feet, and 3) a higher temperature for the feet when the hands are simultaneously cooled. However, the present results on subjective perceptions should be interpreted with peripheral vasoconstriction of fingers and toes while cooling. [ABSTRACT FROM AUTHOR]

STIM1 has been identified as a new warm sensor, but the exact molecular mechanism remains unclear. In this study, a variety of mutants of STIM1, Orai1 and Orai3 were generated. The single–cell calcium imaging and confocal analysis were used to evaluate the thermal sensitivity of the resulting STIM mutants and the interaction between STIM1 and Orai mutants in response to temperature. Our results suggested that the CC1–SOAR of STIM1 was a direct activation domain of temperature, leading to subsequent STIM1 activation, and the transmembrane (TM) region and K domain but not EF–SAM were needed for this process. Furthermore, both the TM and SOAR domains exhibited similarities and differences between STIM1–mediated thermal sensation and store–operated calcium entry (SOCE), and the key sites of Orai1 showed similar roles in these two responses. Additionally, the TM23 (comprising TM2, loop2, and TM3) region of Orai1 was identified as the key domain determining the STIM1/Orai1 thermal response pattern, while the temperature reactive mode of STIM1/Orai3 seemed to result from a combined effect of Orai3. These findings provide important support for the specific molecular mechanism of STIM1–induced thermal response, as well as the interaction mechanism of STIM1 with Orai1 and Orai3 after being activated by temperature. [ABSTRACT FROM AUTHOR]

In order to study the characteristics of postpartum women's heat preference in winter climate, improve their comfort and satisfaction, and promote their postpartum recovery. The postpartum women at different stages were investigated by questionnaire, coupled with the thermal environment parameters tested on site. And analysis of their subjective thermal response and behavior habits. Results showed that there were differences in thermal preference among postpartum women at different stages, and the most significant difference was from 1 to 2 years after delivery. They generally had a warm preference. Among the parameters investigated, postpartum women at this stage were more sensitive to temperature and humidity of thermal environment, and disease, postpartum time, BMI and physical activity were the influencing factors of maternal heat preference. [ABSTRACT FROM AUTHOR]