Effect of Clothing Fabric on 20-km Cycling Performance in Endurance Athletes

Purpose: Examine the effect of synthetic fabrics (SYN, 60% polyester: 40% nylon) vs. 100% cotton fabric (CTN) on the 20-km cycling time trial (20 kmCTT) performance of competitive cyclists and triathletes.Methods: In this randomized controlled crossover study, 15 adults (5 women) aged 29.6 ± 2.7 years (mean ± SE) with a peak rate of O2 consumption of 60.0 ± 2.0 ml/kg/min completed a 20 kmCTT under ambient laboratory conditions (24.3 ± 0.7°C and 17 ± 7% relative humidity) with a simulated wind of ~3 m/s while wearing SYN or CTN clothing ensembles. Both ensembles were of snowflake mesh bi-layer construction and consisted of a loose-fitting long-sleeved shirt with full-length trousers.Results: Participants maintained a significantly (p < 0.05) higher cycling speed and power output over the last 6-km of the 20 kmCTT while wearing the SYN vs. CTN ensemble (e.g., by 0.98 km/h and 18.4 watts at the 20-km mark). Consequently, 20 kmCTT duration was significantly reduced by 15.7 ± 6.8 sec or 0.8 ± 0.3% during SYN vs. CTN trials (p < 0.05). Improved 20 kmCTT performance with SYN vs. CTN clothing could not be explained by concurrent differences in esophageal temperature, sweat rate, ratings of perceived exertion and/or cardiometabolic responses to exercise. However, it was accompanied by significantly lower mean skin temperatures (~1°C) and more favorable ratings of perceived clothing comfort and thermal sensation during exercise.Conclusion: Under the experimental conditions of the current study, athletic clothing made of synthetic fabrics significantly improved the 20 kmCTT performance of endurance-trained athletes by optimizing selected thermoregulatory and perceptual responses to exercise.

A Thermal Model for Processing Data from Undergarment Sensors in Automatic Control of Actively Heated Clothing

Despite its recent growth in popularity, actively heated clothing still lacks the ability to cope with demanding user scenarios. As many of these deficiencies stem from an absence of automatic control, the authors propose a novel approach using a set of sensors embedded in the clothing to provide data about thermal comfort. Available sensors suffer from a lack of accuracy, as for practical reasons, they cannot be attached to the skin, whose temperature is usually used as a comfort indicator. To determine the magnitude of the problem, the authors conducted experiments, and a thermal model was proposed based on experimental findings; the output from the model was compared with the experimental reference data for three different upper body undergarments. The overall accuracy was found to be good: in most cases, the difference between the computed and reference skin temperatures did not exceed 0.5 °C. Furthermore, the model does not rely on unrealistic assumptions regarding the availability of parameters or measurement data. Our findings demonstrate that it is possible to create a thermal model that, when used for input data processing, allows undergarment temperature to be converted to skin temperature, allowing for automatic control of heating insets.

On the Use of Wearable Face and Neck Cooling Fans to Improve Occupant Thermal Comfort in Warm Indoor Environments

Face and neck cooling has been found effective in improving thermal comfort during exercise in the heat despite the fact that the surface area of human face and neck regions accounts for only 5.5% of the entire body. Presently very little documented research has been conducted to investigate cooling the face and neck only to improve indoor thermal comfort. In this study, two highly energy efficient wearable face and neck cooling fans were used to improve occupant thermal comfort in two warm indoor conditions (30 and 32 °C). Local skin temperatures and perceptual responses while using the two wearable cooling fans were examined and compared. Results showed that both cooling fans could significantly reduce local skin temperatures at the forehead, face and neck regions by up to 2.1 °C. Local thermal sensation votes at the face and neck were decreased by 0.82–1.21 scale unit at the two studied temperatures. Overall TSVs decreased by 1.03–1.14 and 1.34–1.66 scale units at 30 and 32 °C temperatures, respectively. Both cooling fans could raise the acceptable HVAC temperature setpoint to 32.0 °C, resulting in a 45.7% energy saving over the baseline HVAC setpoint of 24.5 °C. Furthermore, occupants are advised to use the free-control cooling mode when using those two types of wearable cooling fans to improve thermal comfort. Finally, despite some issues on dry eyes and dry lips associated with those wearable cooling fans, it is concluded that those two highly energy-efficient wearable cooling fans could greatly improve thermal comfort and save HVAC energy.

Core-sheath Electrospinning of Shea Butter and Cellulose Acetate to Enhance Heat Transfer in Protective Clothing

Protective clothing for health workers requires heat transfer in hot and humid environments. To study the thermal conduction of phase-change materials and protect them from leakage, we selected skin-friendly shea-butter due to its suitable melting temperature, and the electrospinning processibility of biocompatible cellulose acetate. The shea-butter as a phase-change material was encapsulated in electrospun cellulose acetate fibres within a core/sheath structure, which was stabilised by two concentric Taylor cones during coaxial electrospinning. Transmission and scanning electron microscopy revealed a blood-in-tube vessel-like morphology. Next, differential scanning calorimetry and thermogravimetric analyses confirmed the heat capacity of shea-butter (latent heat of fusion: 42.73 J/g; thermal conductivity: 1.407 W/m∙K). The flow rate of the core was proportional to the heat capacity of the shea-butter/cellulose acetate fibres. This was consistent with the finding that the electrospun fibres of the highest-ratio shea-butter (16.19%) had the highest thermal conductivity (0.421 J/g∙K). The shea-butter:cellulose acetate ratio was approximately 15:80. The efficacy of heat transfer for the core/sheath fibres in human clothing was assessed by measuring skin temperatures at 13 sites in six males aged 25 to 35 under two conditions: wearing a mask and hood with attached cellulose acetate fibres in the presence and absence of shea-butter. The mean difference in skin temperatures (0.5 ℃) between the two conditions was significant. Coaxial electrospinning of shea-butter/cellulose acetate fibres is therefore promising for protective clothing with efficient heat-transfer in the use of a large area.

A randomized cross-over trial investigating differences in 24-h personal air and skin temperatures using wearable sensors between two climatologically contrasting settings

The influence of elevated air temperatures recorded in various urban microenvironments in adversely impacting biologically relevant disease end points has not yet been extensively tackled. This study is a post hoc analysis of the TEMP pilot trial, a randomized 2 × 2 cross-over trial that examined changes in metabolic and stress hormonal profiles of healthy adults in two settings (urban vs. rural) with distinctly different climatological characteristics during the Mediterranean summer. This analysis aimed to study the association between the 24-h personal air or skin temperature sensor measurements and the diary-based location type (indoors vs. outdoors) in urban (seaside) vs. rural (higher in altitude) microenvironments. Out of 41 eligible participants, a total of 37 participants were included in this post-hoc TEMP trial analysis. Wearable sensors recorded personal air temperature, skin temperature, and activity (as a surrogate marker of physical activity) in each setting, while a time-stamped personal diary recorded the types of indoor or outdoor activities. Temperature peaks during the 24-h sampling period were detected using a peak finding algorithm. Mixed effect logistic regression models were fitted for the odds of participant location (being indoors vs. outdoors) as a function of setting (urban vs. rural) and sensor-based personal temperature data (either raw temperature values or number of temperature peaks). During the study period (July–end of September), median [interquartile range, IQR] personal air temperature in the rural (higher altitude) settings was 1.5 °C lower than that in the urban settings (27.1 °C [25.4, 29.2] vs. 28.6 °C [27.1, 30.5], p < 0.001), being consistent with the Mediterranean climate. Median [IQR] personal air temperature in indoor (micro)environments was lower than those in outdoors (28.0 °C [26.4, 30.3] vs 28.5 °C [26.8, 30.7], p < 0.001). However, median [IQR] skin temperature was higher in indoor (micro)environments vs. outdoors (34.8 °C [34.0, 35.6] and 33.9 °C [32.9, 34.8], p < 0.001) and the number of both personal air and skin temperature peaks was higher indoors compared to outdoors (median [IQR] 3.0 [2.0,4.0] vs 1.0 [1.0,1.3], p < 0.007, for the skin sensors). A significant association between the number of temperature peaks and indoor location types was observed with either the personal air sensor (OR 3.1; 95% CI 1.2–8.2; p = 0.02) or the skin sensor (OR 3.7; 95% CI 1.4–9.9; p = 0.01), suggesting higher number of indoor air temperature fluctuations. Amidst the global climate crisis, more population health studies or personalized medicine approaches that utilize continuous tracking of individual-level air/skin temperatures in both indoor/outdoor locations would be warranted, if we were to better characterize the disease phenotype in response to climate change manifestations.

On the use of facial and neck cooling to improve indoor occupant thermal comfort in warm conditions

Face and neck cooling has been found effective to improve thermal comfort during exercise in the heat despite the surface area of human face and neck regions accounts for only 5.5% of the entire body. Presently, very limited work in the literature has been reported on face and neck cooling to improve indoor thermal comfort. In this work, two energy-efficient wearable face and neck cooling fans were used to enhance occupant thermal comfort in two warm indoor conditions (30 & 32 °C). Local skin temperatures and perceptual responses while using those two wearable cooling fans were examined and compared. Results showed that both cooling fans could largely reduce local skin temperatures at the forehead, face and neck regions up to 2.1 °C. Local thermal sensation votes at the face and neck were decreased by 0.82-1.21 scale unit at two studied temperatures. Overall TSVs dropped by 1.03-1.14 and 1.34-1.66 scale unit at 30 and 32 °C temperatures, respectively. Both cooling fans could extend the acceptable HVAC temperature setpoint to 32.0 °C, resulting in an average energy saving of 45.7% as compared to the baseline HVAC setpoint of 24.5 °C. Further, the free-control cooling mode is recommended to occupants for further improving thermal comfort while using those two types of wearable cooling fans indoors. Lastly, it is concluded that those two wearable cooling fans could greatly improve thermal comfort and save HVAC energy despite some issues on dry eyes and dry lips associated with those wearable cooling fans were noted.

Quantifying Occupational Stress in Intensive Care Unit Nurses: An Applied Naturalistic Study of Correlations Among Stress, Heart Rate, Electrodermal Activity, and Skin Temperature

Objective To identify physiological correlates to stress in intensive care unit nurses. Background Most research on stress correlates are done in laboratory environments; naturalistic investigation of stress remains a general gap. Method Electrodermal activity, heart rate, and skin temperatures were recorded continuously for 12-hr nursing shifts (23 participants) using a wrist-worn wearable technology (Empatica E4). Results Positive correlations included stress and heart rate (ρ = .35, p < .001), stress and skin temperature (ρ = .49, p < .05), and heart rate and skin temperatures (ρ = .54, p = .0008). Discussion The presence and direction of some correlations found in this study differ from those anticipated from prior literature, illustrating the importance of complementing laboratory research with naturalistic studies. Further work is warranted to recognize nursing activities associated with a high level of stress and the underlying reasons associated with changes in physiological responses. Application Heart rate and skin temperature may be used for real-time detection of stress, but more work is needed to validate such surrogate measures.

Comparative Efficacy of Physiological Responses and Skin Temperatures in Indigenous and Crossbred Cattle Supplemented with Chlorophytum borivilianum in Summer Season

Background: Heat stress causes oxidative stress and declines milk production potential of cows. The physiological responses and skin temperature of heat stressed animals are good indices for deterring the heat stress. The efficacy of medicinal herb Chlorophytum borivilianum (CB) was tested in lowering the rise in values of physiological responses and skin temperature in crossbred vis a vis Indigenous cows. Methods: Eighteen Tharparkar (TP) and Crossbred KF cows in mid-lactation were given; No supplement (control), a low (T1, n=6) and a high dose (T2, n=6) of CB @ 40 and 80 mg/kg BW/day, respectively for 90 days during hot-humid season. Respiration rate (RR), pulse rate (PR), rectal temperature (RT) and skin temperature (ST) was recorded at the site of forehead, neck, rear body, and udder surface in the morning and afternoon at weekly intervals. Temperature-humidity index (THI) was calculated to assess the degree of thermal stress in animals. Result: Physiological responses and skin temperatures were higher (p less than 0.01) in the afternoon than morning intervals in TP and KF cows. CB feeding significantly lowered physiological responses and ST (p less than 0.01) in high dose as compared to low dose. It was concluded that CB feeding @ 80 mg/kg BW/day effectively alleviates the heat stress. Indigenous cows were found more heat tolerant in comparison to crossbred cows.

992 Infrared Thermal Imaging in The Diagnosis and Management of Upper Limb Trauma

Aim Trauma can affect perfusion and thereby the temperature of the injured area. Infrared thermal imaging (IRT) has been used as a non-invasive, non-ionising means of diagnosing and monitoring various pathologies. We aim to evaluate the role of IRT in upper limb trauma. Method A review of all literature from the Cochrane Database, PubMed, Medline and EMBASE was performed. All papers evaluating infrared thermal imaging in trauma of the upper limb were included. Exclusion criteria included animal or cadaveric studies, and studies not measuring outcomes related to thermal imaging. Results Six papers were included from a total of 149 papers. There were five observational studies (with limited population numbers) and one case report. Four studies (N = 217) identified significantly higher skin temperatures in fractured limbs compared to non-injured side (p ≤ 0.05). Two studies included follow-ups with skin temperature differences between injured and non-injured sides decreasing over time, consistent with fracture healing times (approximately 3-4 weeks for paediatrics and 6 weeks for adults). One study (N = 9) identified that the presence of activity-related chronic pain in the hand was consistent with higher mean skin temperatures, even at baseline (p = 0.00000795). Conclusions IRT has been successfully used as a means of diagnosis and monitoring fracture healing in the upper limb. It also shows potential for use in detecting fractures that may not be initially evident on x-ray in the acute setting e.g., scaphoid fractures. Further robust and higher quality studies with larger patient populations are required.

Physiological Characteristics and Operational Performance of Pilots in the High Temperature and Humidity Fighter Cockpit Environments

During military operations in high-temperature and relative humidity (RH) conditions, the physiological state and combat capability of pilots are affected severely. In a fighter cockpit, experiments were conducted on thirteen voluntary subjects wearing pilot suits at 21 °C/30%, 30 °C/45%, and 38 °C/60% RH, respectively, in order to examine the physiological changes of pilots in combat thoroughly. The target strike performance, core and skin temperatures, pulse rate, and other parameters were measured and investigated. Significant inter-condition differences were noted in the pulse rate, core temperature, mean skin temperatures, and sweat amount, which increased markedly with elevating temperature and RH. Contrastively, blood oxygen saturation (SpO2) dropped with such elevations. Concerning the skin temperature, the chest and back skin temperatures remained stable, while the temperatures at the hands, feet, and lower arms underwent larger changes with the increasing temperature and humidity. At 38 °C/60% RH, the sweat amount was 3.7 times that at 21 °C/30% RH. The subjects’ operational error rates increased as the core temperatures rose, showing high correlations (r2 = 0.81). The results could serve as a theoretical basis for the design of pilot protective equipment and the control of aircraft cockpit temperature.