George Havenith

A patient-centred system that leverages the analysis of sweat via wearable sensors may better support the management of patients with substance-use disorders.

The majority of research dealing with the impacts of the Himalayan climate on human physiology focuses on low air temperature, high wind speed, and low air pressure and oxygen content, potentially leading to hypothermia and hypoxia. Only a few studies describe the influence of the weather conditions in the Himalayas on the body’s ability to maintain thermal balance. The aim of the present research is to trace the heat exchange between humans and their surroundings during a typical, 6-day summit attempt of Mount Everest in the spring and winter seasons. Additionally, an emergency night outdoors without tent protection is considered. Daily variation of the heat balance components were calculated by the MENEX_HA model using meteorological data collected at automatic weather stations installed during a National Geographic expedition in 2019–2020. The data represent the hourly values of the measured …

Manual outdoor work is essential in many agricultural systems. Climate change will make such work more stressful in many regions due to heat exposure. The physical work capacity metric (PWC) is a physiologically based approach that estimates an individual's work capacity relative to an environment without any heat stress. We computed PWC under recent past and potential future climate conditions. Daily values were computed from five earth system models for three emission scenarios (SSP1‐2.6, SSP3‐7.0, and SSP5‐8.5) and three time periods: 1991–2010 (recent past), 2041–2060 (mid‐century) and 2081–2100 (end‐century). Average daily PWC values were aggregated for the entire year, the growing season, and the warmest 90‐day period of the year. Under recent past climate conditions, the growing season PWC was below 0.86 (86% of full work capacity) on half the current global cropland. With end …

Abstract ASHRAE Research Project RP-1760 updated the database of western clothing as used in ANSI/ASHRAE Standard 55 (Smallcombe et al. 2021). This paper presents an extension to this database by providing detailed whole body and local insulation values for medical staff and patient clothing for hospital environments. Insulation values of seven medical staff ensembles and three patient ensembles were measured in a static standing posture at 0.2 and 0.4 ms-1(0.66 and 1.31 ft. s-1) air velocities, walking in 0.2 and 1.3 ms-1(0.66 and 4.16 ft. s-1) air velocities, in a sitting posture in 0.2 ms-1(0.66 ft. s-1) air velocity, and for patient clothing on an examination table and on hospital beds at air velocities of 0.2 and 0.4 ms-1(0.66 and 1.31 ft. s-1). Measurements were conducted with a" Newton" manikin with 34 individually controlled zones. In addition, vapor resistance was determined in five ensembles. This new …

The appreciation of textile products highly depends on a satisfactory ‘feel’in fabric-skin contact. The question arising is whether the haptic interpretation of a garment (by hand) is comparable to a feeling produced when it is donned or used in its intended application. Sports T-shirts made from three different fiber types (CO, PES I, PES II) were studied in a pre-and post-purchase scenario by exposing 20 female participants to a hand, a donning (pre-purchase) and running evaluation (post-purchase) in 22 C and 50% relative humidity (RH). Objective measurements such as skin temperatures, heart rate, body sweat loss, and sweat absorption of the garments were recorded. Subjective data was collected during the fabric hand and the donning evaluation as well as within the running protocol after 5 min, 20 min, and 5 min of cool down. Perceptual responses to 12 hand-/skin-feel descriptors (eg, rough, smooth) were rated on a scale from 0 (not at all) to 10 (completely) and a feeling of discomfort was given. No significant differences between a hand and a donning evaluation were found in the rating of the sensations. The hand evaluation provided sufficient information for a comfort response to garment wear. The pre-and post-purchase comparison found a significantly lower perception of the feeling of roughness whilst running with the CO shirt and smoothness during running in PES II. The stickiness and comfort perception increased significantly in the post-purchase wear trial. Hence, moisture on the skin provoked through running influences comfort characteristics as well as the perception on haptic cues in t-shirts. Especially surface related haptic …

Critical environmental limits are temperature-humidity thresholds above which heat balance cannot be maintained for a given metabolic heat production. This study examined the association between individual characteristics [sex, body surface area (AD), aerobic capacity (V̇O2max; L∙min-1), and body mass (mb)] and critical environmental limits in young adults. Forty-four (20 M/24 F; 23±4 yr) subjects were exposed to progressive heat stress in an environmental chamber at two low net metabolic rates (Mnet); minimal activity (MinAct; Mnet = 160±35 W) and light ambulation (LightAmb; Mnet = 259±54 W). In 2 hot-dry (HD; <25% rh) environments, ambient water vapor pressure (Pa = 12 or 16 mmHg) was held constant and dry-bulb temperature (Tdb) was systematically increased. In 2 warm-humid (WH; >50% rh) environments, Tdb was held constant at 34 or 36 °C and Pa was systematically increased. The critical wet …

TO THE EDITOR: We thank Richalet and Hermand (1) for their interest in the cardiovascular response (CVR) model (2) and for challenging the assumption that maximal myocardial function (ie, maximum heart rate and cardiac output; HRmax and COmax, respectively) remains unaffected when altitude exceeds 3 km. In their recent meta-analysis on this topic, published shortly after our revised CVR model submission, Richalet and Hermand (3) provide data opposing the notion that “acute systemic hypoxia does not appear to greatly impact the contractile function of cardiac muscle”(2). Instead, they demonstrate a decline in HRmax of $4.8% per 1 km accent, past an altitude of $2.4 km (3). Note that a threshold of 2.4 km is identified, as this is the altitude where the authors’ linear model estimates no change in HRmax (3). We recognize the importance of the matter highlighted; however, we also note that the data and …

The present study investigated the effect of environmental temperature on the hand-feel perception of textiles. Participants were exposed to three different climate conditions (10 C/20 C/

Climate change is already affecting the workforce in many countries. In order to estimate the impact of climate change on the global economy, and to understand how to keep workers safe, information is needed on how climate affects the workers’ output. This talk will report on the Loughborough contribution to the EU Horizon 2020 HEAT-SHIELD project (https://www. heat-shield. eu/), dealing with estimation/modelling of the worker output in a warming climate.

As a global industry, sport makes potentially significant contributions to climate change through both carbon emissions and influence over sustainability practices. Yet, evidence regarding impacts is uneven and spread across many disciplines. This paper investigates the impacts of sport emissions on climate and identifies knowledge gaps. We undertook a systematic and iterative meta‐analysis of relevant literature (1992–2022) on organized and individual sports. Using a defined search protocol, 116 sources were identified that map to four sport‐related themes: (1) carbon emissions and their measurement; (2) emissions control and decarbonization; (3) carbon sinks and offsets; and (4) behavior change. We find that mega sport events, elite sport, soccer, skiing, and golf have received most attention, whereas grass‐roots and women's sport, activity in Africa and South America, cricket, tennis, and volleyball are …

This study investigated the relationship between thermal perceptions during human wear trials and thermal foot manikin measurements of heat and vapour resistance for five running shoes varying in material and construction. Measurements of thermal/evaporative resistance were performed using a 12-zone sweating thermal-foot manikin. Eleven males performed running trials on five occasions, wearing shoes of same design, differing in materials and construction, to achieve a range of heat/vapour resistances and air permeabilities. Trials in 20°C/60% RH consisted of three phases: 15 min rest, 40 min running, 15 min recovery. In-shoe temperature/humidity were measured at two sites on the left foot. Thermal sensation/wetness perception/thermal comfort were provided for the left foot and four foot regions. Variations in shoe material and construction resulted in differences in thermal and evaporative resistance …

The lack of sensorial input in the e-commerce domain impairs consumers’ online apparel purchases. Therefore, it is important to identify possible compensatory cues to present the ‘feel’ of a garment in an enhanced way. This study investigates how visual interpretation of the feel of fabrics is related to the actual feel. Haptic textile attributes of seven fabric swatches were quantified in an online questionnaire (part I), simulating an online shopping experience. Separately, a physical assessment of samples mailed to participants (part II), simulating an in-person shopping experience, was performed. Part I and II comprised 20 participants each. No robust significant difference was found between sex. The comparison of the visual only and the visual-haptic assessment showed higher variability and lower scores of the haptic attributes in the visual only session. Especially textile surface structure related haptic attributes …

To better understand the perception of sportswear, this paper presents a comprehensive case study comparing the quality of sports t-shirts made from virgin polyester, mechanically recycled polyester and mechanically recycled polyester containing ocean plastic. Based on a field trial, controlled laboratory tests, and physical evaluation, the complex process of garment perception and the challenges of testing it were explored. The features offered by the different levels of garment evaluation were highlighted. The findings from the different levels of garment evaluation led to the hypothesis that in a scenario where consumers interact with sportswear primarily by touching and trying it on, such as in a purchase situation, consumers will make assumptions about physiological comfort, psychological comfort and overall comfort based on sensory/tactile comfort.

The purpose of this study was to characterize thermoregulatory and performance responses of elite road-race athletes, while competing in hot, humid, night-time conditions during the 2019 IAAF World Athletic Championships. Male and female athletes, competing in the 20 km racewalk (n = 20 males, 24 females), 50 km racewalk (n = 19 males, 8 females), and marathon (n = 15 males, 22 females) participated. Exposed mean skin (Tsk) and continuous core body (Tc) temperature were recorded with infrared thermography and ingestible telemetry pill, respectively. The range of ambient conditions (recorded roadside) was 29.3°C–32.7°C air temperature, 46%–81% relative humidity, 0.1–1.7 m·s−1 air velocity, and 23.5°C–30.6°C wet bulb globe temperature. Tc increased by 1.5 ± 0.1°C but mean Tsk decreased by 1.5 ± 0.4°C over the duration of the races. Tsk and Tc changed most rapidly at the start of the races …

A real-time, noninvasive, and clinically applicable aging test in humans has yet to be established. Herein we propose a sweat- and wearable-based test to determine biological age. This test would empower users to monitor their aging process and take an active role in managing their lifestyle and health.

This study aims to close the data gap on the long-term post-purchase garment quality for virgin and recycled polyester sports t-shirts. Long-term overall and perceived quality was assessed through both a real-life year-long wear trial as well as in a laboratory-based, in-store scenario, after repeated washing. Three research questions were addressed: 1) Does the quality perception of virgin and recycled polyester sports t-shirts change with prolonged wear and repeated washing? 2) Is there a difference in the perception of t-shirt quality between a real-life wear test and a laboratory-based, instore scenario after repeated washing? 3) Does the use of different types of recycled and virgin polyester affect the quality perception of sports t-shirts? The quality ratings obtained from the two study designs showed that polyester sports t-shirts were of consistent quality over a one-year wear period and up to 52 wash cycles. Significant differences in the quality rating between the study designs were found only for virgin polyester sports t-shirts. The more pronounced use of tactile cues in the in-store scenario is one explanation for the differences in quality ratings between the two study designs. There was no difference in quality ratings between virgin and recycled polyester sports t-shirts collected during the wear trial, and recycled polyester sports t-shirts performed even better in the in-store scenario after repeated washing.

Critical environmental limits are temperature-humidity thresholds above which heat balance cannot be maintained for a given metabolic heat production. This study examined the association between individual characteristics [sex, body surface area (AD), aerobic capacity (V̇o2max), and body mass (mb)] and critical environmental limits in young adults at low metabolic rates. Forty-four (20 M/24 F; 23 ± 4 yr) subjects were exposed to progressive heat stress in an environmental chamber at two low net metabolic rates (Mnet); minimal activity (MinAct; Mnet = ∼160 W) and light ambulation (LightAmb; Mnet = ∼260 W). In two hot-dry (HD; ≤25% rh) environments, ambient water vapor pressure (Pa = 12 or 16 mmHg) was held constant and dry-bulb temperature (Tdb) was systematically increased. In two warm-humid (WH; ≥50% rh) environments, Tdb was held constant at 34°C or 36°C, and Pa was systematically …

The present study investigated preferences and perceived differences between virgin and recycled polyester sports t-shirts, while monitoring participants’ use and care behaviour during real-life wear. A two-month-long wear trial was conducted with 244 participants who were asked to report their t-shirt preferences, perceived differences between t-shirts, as well as their t-shirt use and care via an online survey. T-shirts with nearly identical textile parameters were used for the trial made from virgin polyester, mechanically recycled polyester, and mechanically recycled polyester containing ocean plastics. The responses to the wear trial questionnaires showed that participants struggled to perceive a difference between the different types of polyester t-shirts, and none of the t-shirt materials was significantly preferred over another. The study gives insights into the participants’ care and use habits of sports t-shirts.

Many populations experience high seasonal temperatures. Pregnant women are considered vulnerable to extreme heat because ambient heat exposure has been linked to pregnancy complications including preterm birth and low birthweight. The physiological mechanisms that underpin these associations are poorly understood. We reviewed the existing research evidence to clarify the mechanisms that lead to adverse pregnancy outcomes in order to inform public health actions. A multi-disciplinary expert group met to review the existing evidence base and formulate a consensus regarding the physiological mechanisms that mediate the effect of high ambient temperature on pregnancy. A literature search was conducted in advance of the meeting to identify existing hypotheses and develop a series of questions and themes for discussion. Numerous hypotheses have been generated based on animal models and …

PurposeSports garments play an important role in the well-being of an athlete by protecting the wearer from changing environmental conditions and providing a comfortable feel. Clothing requirements have changed in recent years and demand for apparel with a higher comfort performance has been rising. Hence, the purpose of this study is to explore consumers’ expectations and perception of comfort and to examine how different textiles are perceived by consumers to provide useful knowledge that allows to engineer comfort into fabrics and sports garments.Design/methodology/approachThis online survey comprised 292 respondents, classified by sex, age, nationality and physical activity. The respondents were asked a total of 18 questions through the Bristol Online Survey tool to explore expectation, perception and preference of clothing comfort, specifically of sportswear.FindingsFit and comfort are closely …