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Background: Stress at workplace arises when the requirements for workers don’t meet their personal or social capabilities, or differ from the individual’s needs and motivation. Occupational stress is observed in a number of both elementary and high-tech occupational fields. In ferrous metallurgy it could be associated with 24/7 operating mode, high work intensity and a variety of unfavorable characteristics of working environment. The aim of the study is to clarify the nature of factors - stressors in ferrous metallurgy and to define ways for reduction of their negative health impact. Materials and Methods: Study subject are 91 workers in an electric steel-making department of a ferrous metallurgy enterprise in Bulgaria. Data, concerning working conditions, work characteristics, workers satisfaction, presence/absence of stress and chronic diseases, were collected by direct individual self-administered questionnaire and documents review. Results: Two of three study subjects reported stress related to their work. Noise, varies from 89.2 to 92.2 dB/A (at rate 85 dB/A) in different sections of the workshop, is the biggest stressor according to 77.5% of the investigated people, followed by short deadlines for task performance (46.5%) and ineffective leadership (32.4%). In addition, negative effects of stress is increasing by high dust levels, reaching up to 7 mg/m3 air at a standard of 6 mg/m3 air, and contain manganese, coke, chamotte, free and bound silica, rare metals, increased concentration of CO and more.Nevertheless workers consider that the organization provides measures for stress reduction by strict control on the limit values of noise, dust, temperature and chemicals (49.2%),provision of personal protective equipment establishment (69%) of a rational mode of work and rest (56.3%) and healthy eating (47.9%). Conclusions: Despite a plenty of environmental and organizational stressors, their negative effects could be decreased by appropriate preventive measures. Key messages: ) Factors-stressor in ferrous metallurgy could be associated with a variety of unfavorable characteristics of working environment,non-stop operating mode, high work intensity and poor time management. ) Noise is the biggest stressor followed by short deadlines for task performance and ineffective leadership. Stressors are modifiable and preventable by strict hygienic control and improved management. [ABSTRACT FROM AUTHOR]

Abstract: This collaborative study is based on the analysis and comparison of results of coordinated experimental investigations conducted in Bulgaria and Azerbaijan for revealing a possible influence of solar activity changes and related geomagnetic activity variations on the human cardio-vascular state. Arterial blood pressure and heart rate of 86 healthy volunteers were measured on working days during a period of comparatively high solar and geomagnetic activity (2799 measurements in autumn 2001 and spring 2002) in Sofia. Daily experimental investigations of parameters of cardio-vascular health state were performed in Azerbaijan with a permanent group of examined persons. Heart rate and electrocardiograms were digitally registered (in total 1532 records) for seven functionally healthy persons on working days and Saturdays, in the Laboratory of Heliobiology at the Medical Center INAM in Baku, from 15.07.2006 to 13.11.2007. Obtained digital recordings were subjected to medical, statistical and spectral analyses. Special attention was paid to effects of solar extreme events, particularly those of November 2001 and December 2006. The statistical method of the analysis of variance (ANOVA) and post hoc analysis were applied to check the significance of the influence of geomagnetic activity on the cardio-vascular parameters under consideration. Results revealed statistically significant increments for the mean systolic and diastolic blood pressure values of the group with geomagnetic activity increase. Arterial blood pressure values started increasing two days prior to geomagnetic storms and kept their high values up to two days after the storms. Heart rate reaction was ambiguous and not significant for healthy persons examined (for both groups) under conditions with geomagnetic activity changes. It is concluded that heart rate for healthy persons at middle latitudes can be considered as a more stable physiological parameter which is not so sensitive to environmental changes while the dynamics of arterial blood pressure reveals a compensatory reaction of the human organism for adaptation. [Copyright &y& Elsevier]

The authors investigated the effects of local and planetary geomagnetic activity on human physiology. They collected data in Sofia, Bulgaria, from a group of 86 volunteers during the periods of the autumnal and vernal equinoxes. They used the factors local/planetary geomagnetic activity, day of measurement, gender, and medication use to apply a four-factor multiple analysis of variance. They also used a post hoc analysis to establish the statistical significance of the differences between the average values of the measured physiological parameters in the separate factor levels. In addition, the authors performed correlation analysis between the physiological parameters examined and geophysical factors. The results revealed that geomagnetic changes had a statistically significant influence on arterial blood pressure. Participants expressed this reaction with weak local geomagnetic changes and when major and severe global geomagnetic storms took place.

The heart rate (h.r.) of normal healthy subjects varies in rest, under high-load conditions and in pathology. The heart rate variability (h.r.v.) integrates many mechanisms in- and outside the central nervous system, which influence and regulate the h.r. Statistical methods have been used to obtain additional information concerning the diagnostic capabilities h.r.v., the correlation between ECG R-R intervals and their variability and the prognostic significance of h.r.v. The benefits of modification of h.r.v. are not well known. In our previous study the h.r.v. of astronauts before, during and after long-term space flight (seven months) was examined. In this study we make analysis of h.r.v. in wake and sleep in different phases during a short-time space flight (9 days) of the Bulgarian astronaut A.A. in 1988.