RESUMO
Abstract High physical overload during the workday and some conditions present in the workplace can generate several losses in the worker's health. The use of tools capable of identifying physical load (PL), such as heart rate (HR) analysis, is essential. The aim of the study was to evaluate the physical load and heart rate behavior of workers in the slaughterhouse. The cardiovascular load reached by two individuals was 12% and 24%. In relation to the PL rating, they fit as moderately heavy to heavy work. The HR, was higher at the end of the work when compared to the beginning. Furthermore, it was pointed out that the temperature, noise, and body mass index were above normality values. The physical workload was classified as moderately heavy to heavy. The limit HR was reached in some moments of the work by one of the workers and two of them reached higher HR values at the end of the work.
Resumo A elevada sobrecarga física durante a jornada de trabalho e algumas condições presentes no ambiente de trabalho podem gerar diversos prejuízos na saúde do trabalhador. A utilização de ferramentas capazes de identificar a carga física (CF), como a análise da frequência cardíaca (FC), é fundamental. O objetivo do estudo foi avaliar o comportamento da carga física e da frequência cardíaca dos trabalhadores de frigorífico. A carga cardiovascular alcançada por dois indivíduos foi de 12% e 24%. Em relação à classificação da CF, enquadram-se como trabalhos moderadamente pesados a pesados. A FC, foi maior no final do trabalho quando comparado ao início. Além disso, apontou-se que a temperatura, o ruído e o índice de massa corporal estavam acima dos valores da normalidade. A CF de trabalho foi classificada como moderadamente pesada a pesada. A FC limite foi atingida em alguns momentos do trabalho por um dos trabalhadores e dois deles atingiram valores maiores de FC ao final do trabalho.
RESUMO
Due to their extremely small size that gives them unique physicochemical properties, nanoparticles (NPs) are used in the production of everyday materials. However, NPs can accumulate in body organs and could cause various diseases. Moreover, NPs that cross biological membranes such as the blood-brain barrier can aggregate in the brain and potentially produce neuronal damage. Although studies have reported the effects of diverse NPs on the bioelectrical properties of individual neurons, their potential influences on the operation of whole neuronal networks have not been documented. Here, we aimed to evaluate the effects of an acute exposure to zinc oxide (ZnO) NPs on the central neural networks responsible for mammalian respiratory rhythm generation. Using an isolated ex vivo brainstem-spinal cord preparation from neonatal rat in which the circuitry for the central respiratory command remained intact, we show that ZnO NPs accelerate, then profoundly disrupt respiratory-related activity produced by the pre-Bötzinger complex (preBötC) responsible for inspiratory rhythm generation. Consequently, a sudden and definitive cessation of respiratory-related activity occurs in ZnO NPs-exposed preparations. Part of these effects is related to zinc ions released from NPs. Using brainstem slice preparations containing the preBötC network, whole-cell patch-clamp recordings revealed that ZnO NPs depolarize preBötC inspiratory neurons and affect their bioelectrical properties by reducing the amplitude of action potentials, thereby leading to a depression of intra-network activity and the ultimate termination of respiratory rhythmogenesis. These findings support the conclusion that ZnO NPs may have deleterious effects on the central respiratory centers of newborn mammals.
