Physiological, cognitive and neuromuscular effects of heat exposure on firefighters after a live training scenario.

This study investigated physiological, cognitive and neuromuscular performances in firefighters after a structural live-fire scenario. Changes in vital signs, environmental parameters and cognitive and neuromuscular performance were measured before and after a live-fire training session in a closed environment, in conditions similar to those one could encounter in a structural fire. Very high ambient temperature peaks were reached during the 30-min sessions. After the session, the forehead temperature was increased by 0.5 °C, mean water body loss was 639 ml and the mean heart rate increase was 7.5 bpm. Mental calculation speed did not vary significantly, however we observed a reduction in reaction time. These findings demonstrated that after 30 min of exposure, heat stress had little impact on firemen. Stress activation seems beneficial after firefighting operations. Normal vital parameters should allow re-engagement for a second firefighting task. This result must be compared with longer exposures.

Uso de sistemas modulares vegetados para promoção da saúde urbana e atenuação do estresse térmico / Urban health promotion and thermal stress attenuation with the use of green roofs

RESUMO O processo de urbanização possui efeitos significativos no microclima local, resultando no surgimento das ilhas de calor e comprometimento das condições térmicas no interior de habitações. A aplicação de sistemas modulares vegetados em telhados ou coberturas surge como alternativa à melhoria das condições térmicas no interior de habitações, dispensando, algumas vezes, a climatização artificial e promovendo melhores condições de salubridade no ambiente. A avaliação da atenuação do estresse foi realizada por meio da comparação entre duas habitações protótipos idênticas em que uma possui telhado e paredes vegetadas, e a outra, não. O estresse térmico foi avaliado com base no Índice de Calor, que considera os efeitos combinados da temperatura e umidade relativa. O sistema modular vegetado exerceu papel importante na atenuação do estresse térmico nas habitações, melhorando os parâmetros das condições de salubridade ambiental e minimizando riscos associados à saúde. Os Índices de Calor máximos registrados nos protótipos não vegetado e vegetado foram 57,5°C e 49,2°C respectivamente. Em termos de atenuação do estresse térmico, a adoção dos sistemas vegetados diminui o tempo de exposição de condições térmicas referentes às condições de 'perigo' a 'perigo extremo' de 17,3% para 5,4%.

ABSTRACT The urbanization process produces significant effects on local microclimate, resulting in heat islands and the worsening of thermal conditions inside housing facilities. The implementation of green roofs arises as an alternative in the improvement of indoor thermal conditions in housings, leading sometimes to energy savings as for air conditioning and promoting better health conditions. The evaluation of thermal stress attenuation was performed by comparing two identical prototype housings, where one has green roof and walls, and the other does not. Thermal stress was evaluated based on the Heat Index, which considers the combined effects of temperature and relative humidity. The green roof system played an important role in the attenuation of thermal stress in housings by improving environmental health conditions and minimizing health related risks. The maximum heat indices recorded in the non-vegetated and vegetated prototypes were 57.5 ° C and 49.2 ° C, respectively. In terms of thermal stress attenuation, the adoption of vegetated (green roof) systems decreases the time of exposure of thermal conditions regarding hazardous and extreme danger conditions from 17.3% to 5.4%.

Exercising in a hot environment with muscle damage: effects on acute kidney injury biomarkers and kidney function.

Unaccustomed strenuous physical exertion in hot environments can result in heat stroke and acute kidney injury (AKI). Both exercise-induced muscle damage and AKI are associated with the release of interleukin-6, but whether muscle damage causes AKI in the heat is unknown. We hypothesized that muscle-damaging exercise, before exercise in the heat, would increase kidney stress. Ten healthy euhydrated men underwent a randomized, crossover trial involving both a 60-min downhill muscle-damaging run (exercise-induced muscle damage; EIMD), and an exercise intensity-matched non-muscle-damaging flat run (CON), in random order separated by 2 wk. Both treatments were followed by heat stress elicited by a 40-min run at 33°C. Urine and blood were sampled at baseline, after treatment, and after subjects ran in the heat. By design, EIMD induced higher plasma creatine kinase and interleukin-6 than CON. EIMD elevated kidney injury biomarkers (e.g., urinary neutrophil gelatinase-associated lipocalin (NGAL) after a run in the heat: EIMD-CON, mean difference [95% CI]: 12 [5, 19] ng/ml) and reduced kidney function (e.g., plasma creatinine after a run in the heat: EIMD-CON, mean difference [95% CI]: 0.2 [0.1, 0.3] mg/dl), where CI is the confidence interval. Plasma interleukin-6 was positively correlated with plasma NGAL (r = 0.9, P = 0.001). Moreover, following EIMD, 5 of 10 participants met AKIN criteria for AKI. Thus for the first time we demonstrate that muscle-damaging exercise before running in the heat results in a greater inflammatory state and kidney stress compared with non-muscle-damaging exercise. Muscle damage should therefore be considered a risk factor for AKI when performing exercise in hot environments.

Outbreak of sudden cardiac deaths in a tire manufacturing facility: can it be caused by nanoparticles?

OBJECTIVES: The purpose of this study was to review clinical characteristics and working environments of sudden cardiac death (SCD) cases associated with a tire manufacturer in Korea, and review possible occupational risk factors for cardiovascular disease including nanoparticles (ultrafine particles, UFPs). METHODS: We reviewed (i) the clinical course of SCD cases and (ii) occupational and non-occupational risk factors including chemicals, the physical work environment, and job characteristics. RESULTS: Possible occupational factors were chemicals, UFPs of rubber fume, a hot environment, shift work, overworking, and noise exposure. The mean diameter of rubber fume (63-73 nm) was (larger than diesel exhaust [12 nm] and outdoor dust [50 nm]). The concentration of carbon disulfide, carbon monoxide and styrene were lower than the limit of detection. Five SCD cases were exposed to shift work and overworking. Most of the cases had several non-occupational factors such as hypertension, overweight and smoking. CONCLUSION: The diameter of rubber fume was larger than outdoor and the diesel exhaust, the most well known particulate having a causal relationship with cardiovascular disease. The possibility of a causal relation between UFPs of rubber fume and SCD was not supported in this study. However, it is necessary to continue studying the relationship between large sized UFPs and SCD.

Outbreak of Sudden Cardiac Deaths in a Tire Manufacturing Facility: Can It Be Caused by Nanoparticles?

OBJECTIVES: The purpose of this study was to review clinical characteristics and working environments of sudden cardiac death (SCD) cases associated with a tire manufacturer in Korea, and review possible occupational risk factors for cardiovascular disease including nanoparticles (ultrafine particles, UFPs). METHODS: We reviewed (i) the clinical course of SCD cases and (ii) occupational and non-occupational risk factors including chemicals, the physical work environment, and job characteristics. RESULTS: Possible occupational factors were chemicals, UFPs of rubber fume, a hot environment, shift work, overworking, and noise exposure. The mean diameter of rubber fume (63-73 nm) was (larger than diesel exhaust [12 nm] and outdoor dust [50 nm]). The concentration of carbon disulfide, carbon monoxide and styrene were lower than the limit of detection. Five SCD cases were exposed to shift work and overworking. Most of the cases had several non-occupational factors such as hypertension, overweight and smoking. CONCLUSION: The diameter of rubber fume was larger than outdoor and the diesel exhaust, the most well known particulate having a causal relationship with cardiovascular disease. The possibility of a causal relation between UFPs of rubber fume and SCD was not supported in this study. However, it is necessary to continue studying the relationship between large sized UFPs and SCD.

Exertional Heat Stroke in a Young Man with Multi-organ Dysfunction and Fulminant Pneumonia

Heat stroke is defined as a core body temperature that rises above 40 degrees C accompanied by central nervous system abnormalities such delirium, convulsions or coma. Despite treatment with optimal cooling, heat stroke causes deaths by complications including rhabdomyolysis, renal failure, hepatic dysfunction, disseminated intravascular coagulation syndrome, acute respiratory distress syndrome, bowel ischemia, myocardial injury, and multiple organ failure. In some cases of survival, heat stroke it can cause irreversible CNS damage. Therefore, if exertional heat stroke is properly diagnosed in the emergency room, we must initiate early and aggressive treatment in order to prevent the multiorgan failure and high mortality associated with this condition. To our knowledge, case reports in the literature are rare describing that patients with multiple organ dysfunction and fulminant pneumonia following exertional heat stroke. This study reports on a relevant case, as well as findingsfrom the literature. The case history is presented of a 20- year-old man who presented with exertional heat stroke with sustained hyperpyrexia ongoing after the first day of admission despite optimal treatment including intensive fluid resuscitation. On the 3rd day of admission, chest infiltrated lesions were discovered. From the high-resolution computed tomography results, multifocal consolidations were discovered in both lungs. Blood cultures revealed Staphylococcus hominis. Treatment with proper antibiotics was begun after identifying the blood culture. The patient fully recovered and was discharged on the 10th day after admission.