Comparison of two telemetric intestinal temperature devices with rectal temperature during exercise.

OBJECTIVE: The discomfort caused by rectal probes and esophageal probes for the estimation of body core temperature has triggered the development of gastrointestinal (GI) capsules that are easily accepted by athletes and workers due to their non-invasive characteristics. We compare two new GI capsule devices with rectal temperature during cycle ergometer exercise and rest. APPROACH: Eight participants followed a protocol of (i) 30 min exercise with a power output of 130 W, (ii) 5 min rest, (iii) 10 min self-paced maximum exercise, and (iv) 15 min rest. Core temperature was measured using two GI-capsule devices (e-Celsius and myTemp) and rectal temperature. MAIN RESULTS: The myTemp system provided only slightly different temperatures to the rectal temperature probe during rest and exercise. However, the factory-calibrated e-Celsius system showed a systematic rectal temperature underestimation of 0.2 °C that is corrected in the 2018 versions. Both GI capsules reacted faster to temperature changes in the body compared to the rectal temperature probe during the rest period following maximum exercise. SIGNIFICANCE: The GI-capsules react faster to temperature changes in the body compared to the rectal temperature probe, in particular during the rest period following exercise.

Thermal sensation models: a systematic comparison.

Thermal sensation models, capable of predicting human's perception of thermal surroundings, are commonly used to assess given indoor conditions. These models differ in many aspects, such as the number and type of input conditions, the range of conditions in which the models can be applied, and the complexity of equations. Moreover, the models are associated with various thermal sensation scales. In this study, a systematic comparison of seven existing thermal sensation models has been performed with regard to exposures including various air temperatures, clothing thermal insulation, and metabolic rate values after a careful investigation of the models' range of applicability. Thermo-physiological data needed as input for some of the models were obtained from a mathematical model for human physiological responses. The comparison showed differences between models' predictions for the analyzed conditions, mostly higher than typical intersubject differences in votes. Therefore, it can be concluded that the choice of model strongly influences the assessment of indoor spaces. The issue of comparing different thermal sensation scales has also been discussed.

Materials used to simulate physical properties of human skin.

BACKGROUND: For many applications in research, material development and testing, physical skin models are preferable to the use of human skin, because more reliable and reproducible results can be obtained. PURPOSE: This article gives an overview of materials applied to model physical properties of human skin to encourage multidisciplinary approaches for more realistic testing and improved understanding of skin-material interactions. METHODS: The literature databases Web of Science, PubMed and Google Scholar were searched using the terms 'skin model', 'skin phantom', 'skin equivalent', 'synthetic skin', 'skin substitute', 'artificial skin', 'skin replica', and 'skin model substrate.' Articles addressing material developments or measurements that include the replication of skin properties or behaviour were analysed. RESULTS: It was found that the most common materials used to simulate skin are liquid suspensions, gelatinous substances, elastomers, epoxy resins, metals and textiles. Nano- and micro-fillers can be incorporated in the skin models to tune their physical properties. CONCLUSION: While numerous physical skin models have been reported, most developments are research field-specific and based on trial-and-error methods. As the complexity of advanced measurement techniques increases, new interdisciplinary approaches are needed in future to achieve refined models which realistically simulate multiple properties of human skin.

Real evaporative cooling efficiency of one-layer tight-fitting sportswear in a hot environment.

Real evaporative cooling efficiency, the ratio of real evaporative heat loss to evaporative cooling potential, is an important parameter to characterize the real cooling benefit for the human body. Previous studies on protective clothing showed that the cooling efficiency decreases with increasing distance between the evaporation locations and the human skin. However, it is still unclear how evaporative cooling efficiency decreases as the moisture is transported from the skin to the clothing layer. In this study, we performed experiments with a sweating torso manikin to mimic three different phases of moisture absorption in one-layer tight-fitting sportswear. Clothing materials Coolmax(®) (CM; INVISTA, Wichita, Kansas, USA; 100%, profiled cross-section polyester fiber), merino wool (MW; 100%), sports wool (SW; 50% wool, 50% polyester), and cotton (CO; 100%) were selected for the study. The results demonstrated that, for the sportswear materials tested, the real evaporative cooling efficiency linearly decreases with the increasing ratio of moisture being transported away from skin surface to clothing layer (adjusted R(2) >0.97). In addition, clothing fabric thickness has a negative effect on the real evaporative cooling efficiency. Clothing CM and SW showed a good ability in maintaining evaporative cooling efficiency. In contrast, clothing MW made from thicker fabric had the worst performance in maintaining evaporative cooling efficiency. It is thus suggested that thin fabric materials such as CM and SW should be used to manufacture one-layer tight-fitting sportswear.