The effect of exposure to cold on dexterity and temperature of the skin and hands.

Objectives. This study aimed to determine the impact of low temperature (-1 °C, +5 °C) on manual dexterity and hand skin temperature after 1 h of exposure when using two types of protective gloves. Methods. Ten male participants wore double gloves or single gloves, when spending 1 h in a climatic chamber at -1, +5 or +20 °C. Before and after the cold exposure, measurements of mean weighted body skin temperature, hand skin temperature, the Purdue Pegboard Test and hand grip strength were performed. Results. There were statistically significant differences in the values of mean weighted body skin temperature and left and right hand skin temperature between the study variants. Conclusion. No effect of cold exposure (-1 °C, +5 °C) on manual dexterity was observed, but there was an effect of -1 °C temperature change on weighted mean skin temperature and hand skin temperature during 1 h of exposure. The decrease in both right and left hand skin temperature after cold exposure was the largest for -1 °C while using single gloves, and differed significantly from the other variants.

Psychomotor Performance after 30 h of Sleep Deprivation Combined with Exercise.

Sleep deprivation (SD) usually impairs psychomotor performance, but most experiments are usually focused on sedentary conditions. The purpose of this study was to evaluate the influence of 30 h of complete SD combined with prolonged, moderate exercise (SDE) on human psychomotor performance. Eleven endurance-trained men accustomed to overnight exertion were tested twice: in well-slept and non-fatigued conditions (Control) and immediately after 30 h of SDE. They performed a multiple-choice reaction time test (MCRT) at rest and during each workload of the graded exercise test to volitional exhaustion. At rest, the MCRT was shorter after SDE than in the Control (300 ± 13 ms vs. 339 ± 11 ms, respectively, p < 0.05). During graded exercise, there were no significant differences in MCRT between groups, but the fastest reaction was observed at lower workloads after SDE (158 ± 7 W vs. 187 ± 11 W in Control, p < 0.05). The total number of missed reactions tended to be higher after SDE (8.4 ± 0.7 vs. 6.3 ± 0.8 in Control, p = 0.06). In conclusion, SDE is different from SD alone; however, well-trained men, accustomed to overnight exertion can maintain psychomotor abilities independently of the extent of central fatigue. Exercise can be used to enhance psychomotor performance in sleep-deprived subjects in whom special caution is required in order to avoid overload.

Lifestyle and environmental factors may induce airway and systemic inflammation in firefighters.

Health status depends on multiple genetic and non-genetic factors. Nonheritable factors (such as lifestyle and environmental factors) have stronger impact on immune responses than genetic factors. Firefighters work is associated with exposure to air pollution and heat stress, as well as: extreme physical effort, mental stress, or a changed circadian rhythm, among others. All these factors can contribute to both, short-term and long-term impairment of the physical and mental health of firefighters. Increased levels of some inflammatory markers, such as pro-inflammatory cytokines or C-reactive protein (CRP) have been observed in firefighters, which can lead to local, acute inflammation that promotes a systemic inflammatory response. It is worth emphasizing that inflammation is one of the main hallmarks of cancer and also plays a key role in the development of cardiovascular and respiratory diseases. This article presents possible causes of the development of an inflammatory reaction in firefighters, with particular emphasis on airway inflammation caused by smoke exposure.

Hydration Status in Men Working in Different Thermal Environments: A Pilot Study.

The aim of this study was to determine the effects of different seasons of the year and the time of day (before work vs. after work) on hydration status in men. The study involved sixty foresters who spent most of the work outdoors. During three seasons of the year (summer, autumn, and winter), indices of hydration status (body mass (BM) and percentage change of BM, total body water (TBW) and percentage change of TBW, serum osmolality (Sosm) and percentage change of Sosm, urine osmolality, urine-specific gravity (USG), urine color, and thirst) were determined before work on the first day (time point 1 used as baseline), immediately after work on the first day (time point 2), and before work on the following day (time point 3). USG decreased at time point 2 compared to time point 1 (p < 0.001) and time point 3 (p = 0.03). At time point 2 (p = 0.002) in winter and time point 3 in autumn (p = 0.049), serum osmolality was higher than in summer. In conclusion, the differences in hydration status depended on the time of day and season. A large percentage of foresters come to work inadequately hydrated, especially in colder seasons compared to summer.

Cooling Effect of Phase Change Materials Applied in Undergarments of Mine Rescuers in Simulated Utility Conditions on Thermal Manikin.

The cooling effect of new undergarments (T-shirt) with PCM was measured using heat flux on a thermal manikin according to four tests variants: in T-shirt without PCM, in T-shirt with PCM, in T-shirt without PCM and with outerwear, in T-shirt with PCM and with outerwear. The tests were done in the climatic chamber under controlled conditions: ta = 32 °C, RH = 70% and Va = 1 m/s. The cooling effect was confirmed by thermograms taken by thermal imaging cameras located on the front and back of the manikin. The results showed that in the case of using a T-shirt with PCM, the effect of heat absorption was observed during the first several dozen minutes of operation. The mean value of the heat flux density (ΔHc) received from the manikin was +15 W/m2. In the case of using outerwear with a T-shirt with PCM, the mean value of the heat flux density (ΔHc) received from the manikin was +31.5 W/m2.

The Impact of Protective Gloves on Manual Dexterity in Cold Environments-A Pilot Study.

Our research aimed to determine the impact of two types of protective gloves. The research tested the glove performance on men exposed to a range of temperatures reflecting the working conditions in fruit and vegetable processing. The gloves were assessed for performance within the time required to complete a specific manual task and for performance relative to the subjective thermal sensations in the male subjects. Six males participated in a total of 3 study variants: at +5 °C (with double gloves and single glove), at -1 °C (with double gloves and single glove) and in reference conditions +20 °C (without gloves), in which they performed manual tasks. The measurement of manual task performance time was used to assess manual dexterity. Subjective thermal sensations were determined. Differences in the time required to complete specific tasks were observed between the variants with gloves (both at a temperature of +5 °C and -1 °C), and without gloves (p < 0.05). The type of protective gloves had an impact on the time needed to complete manual tasks and therefore may affect manual dexterity.

The influence of air humidity on human heat stress in a hot environment.

This article aims to present the physical adaptation capabilities of a human, seen as a response to extreme hot and dry or hot and humid conditions. Adaptation capabilities are expressed as safe exposure time in two variants: at rest and during physical activity. The study shows the results of calculations of the variability over time of the core temperature and skin temperature as well as heat balance. Calculations were made according to Standard No. EN ISO 7933:2005 on the basis of assumed and actual meteorological data. The results of the calculations show that in these conditions a hot but dry environment enables a human (although to a limited extent) to stay and perform low physical activity, provided access to drinking water is ensured. In contrast, a hot but humid environment causes more serious problems, due to the inability to reduce skin temperature by evaporation of sweat from the skin surface.

Physiological tests on firefighters whilst using protective clothing.

In addition to the intense effort of firefighters during rescue operations and an adverse thermal environment, the properties of clothing can also hinder the performance of occupational activities. The heat load of firefighters during diversified effort in a climate chamber was compared for two types of protective clothing (barrack [B] clothing and barrack under special-purpose [S] clothing) at two levels of air temperature (20 and 30 °C). During testing, physiological parameters of heat strain were measured and subjective ratings were collected. There was a small increase in physiological parameters and subjective ratings at 20 °C in S clothing compared to the results in B clothing, whereas those differences were substantial at 30 °C. So, the structure of S clothing, which ensures protection of firefighters against high temperatures and flames, and its watertight layer make it significantly more difficult for the body to give off heat.

Effect of previous lowering of skin temperature on the time of safe exposure to a hot environment: a case study.

Objective. The purpose of the study was to determine the influence of initial conditions of a microclimate on volunteers' permissible exposure limits to a hot and humid environment. Materials and methods. Eighteen experimental studies with the participation of three volunteers were performed under controlled microclimate conditions (two climate chambers). The skin temperature and body core temperature were measured after they had stabilized in the following microclimate conditions: temperature of 17, 21 and 23 °C, relative humidity of 50% and hot microclimate conditions, i.e., temperature of 35 and 42 °C, humidity of 80% and physical work load at 30 W. The time needed to reach a body core temperature of 38 °C was determined under hot conditions. Heat accumulation was calculated. Results. Lowering volunteers' skin temperature under conditions of stabilized physiological parameters prolongs the time necessary for the body core temperature to reach 38 °C during physical work in a hot and humid environment. Conclusions. Appropriate acclimatization before exposure may prolong the time of safe work in a hot environment, e.g., during activities of rescue services.

Parabrachiella jarai sp. nov. (Crustacea: Copepoda: Siphonostomatoida) parasitic on Sillago sihama (Actinopterygii: Perciformes: Sillaginidae).

The presently reported study provides a detailed morphological description of the female and the male of a new species of the genus Parabrachiella-Parabrachiella jarai sp. nov. The parasites were sampled from marine fish, silver sillago, Sillago sihama (Perciformes: Sillaginidae), captured in Malaysia in 1994 and Hong Kong in 1995. The new species bears some resemblance to Parabrachiella lata (Song et Chen, 1976) but differs from it in details of second antenna, mandible, and maxilliped. The genus Parabrachiella currently covers 67 species including those recently transferred from Neobrachiella Kabata, 1979. An amended generic diagnosis is proposed for Parabrachiella and Thysanote. Some members of Parabrachiella are herewith transferred to Thysanote and some Thysanote are now placed in Parabrachiella.