Objectives: In Poland, occupational exposure to cold microclimate is quite common (5.1 workers/1000 occupationally active people). Reports on health effects of this exposure are rather scarce. The aim of the study was to evaluate the physiological reaction in workers occupationally exposed to cold microclimate. Materials and Methods: Examinations were performed in a group of 102 workers (41 women and 61 men) employed at cold storage units. The mean age in the group was 39.1 ± 9.9 years and the duration of employment under conditions of cold environment was over 12 years. The study population was divided into four groups, according to microclimate conditions (group I, ambient temperature -26°C; group II, 10-14°C; group III, 18-20°C, control group; and group IV, 0-10°C). The workers underwent the following procedures: general medical examinations, cold pressor test, ambulatory blood pressure monitoring, and heart rate variability (HRV) analysis (time-and frequency-domain parameters). Results: The results were adjusted for confounding factors (age, smoking and drinking habits). The analysis of HRV parameters did not reveal any significant differences between the study groups. However, systolic and diastolic blood pressure (BP) in the daytime and at night was significantly higher in group IV compared to group II. Mean heart rate (HR) in the daytime and at night and the BP and HR day/night ratio did not differ between the groups. The analysis of BP by gender revealed that in women, systolic BP during the day and at night was significantly higher in group IV than in group II. In the group of workers with hypertension (18 men and 5 women), men reacted to the cold pressor test either by increased or decreased BP while all the women reacted by the increased BP. Conclusions: Our findings indicated that in workers exposed to cold microclimate, the physiological reaction was dependent on gender and ambient temperature. Women seemed to be more sensitive to cold stress than men. However, this finding must be further investigated.

Objectives: Epidemiological studies provide evidence that airborne particulate matter may contribute to the increased incidence and mortality rates due to pulmonary and cardiovascular diseases. Only some of them address the problem of occupational exposure to particulate air pollution. The aim of our study was to assess cardiovascular reaction and autonomic regulation in workers exposed to fine particles. Materials and Methods: All workers had medical examination, resting ECG with heart rate variability analysis (HRV), 24-h ECG, and ambulatory blood pressure monitoring (ABPM) performed. The subjects were 20 male workers (mean age: 32.14.0 year) of a ceramic ware factory exposed to the dust and 20 workers who were not exposed (mean age: 39.4±7.8 year). The period of employment under exposure amounted to 5.6±2.1 year. Dust exposure was measured using individual dosimeters. Results: The geometric mean total dust concentration was 44±1.5 mg/m 3 and the FPD (fine particulate dust) concentration amounted to 11.5±1.6 mg/m 3 . No abnormalities were noted in the resting ECG in both groups, in 24-h ECG 2 subjects, both from exposed and control groups, had ventricular heart rhythm and repolarization disturbances. Blood pressure in ABPM, both systolic as well as diastolic, was normal and did not differ between the groups. Resting heart rate in the exposed group was significantly lower (p = 0.038) than in the control group. In the exposed group STD R-R from short-term records was significantly higher (p = 0.01). Fast Fourier Transform (FFT) analysis showed that the low frequency power spectrum (LF) did not differ in the exposed and the control group, while high frequency (HF) was significantly higher in the exposed group. LF/HF ratio was significantly lower in the exposed in comparison with the control group. Conclusions: Although we did not reveal significant abnormalities in ECG as well as in ABPM in the exposed group, it seems that neurovegetative disturbances (parasympathetic predominance) may serve as an early indicator of fine particulate dust effect on cardiovascular system. Key words:Ceramic industry, Heart rate variability, Air pollution, Respirable dust, Blood pressure monitoring, ABPM This study was supported by Nofer Institute of Occupational Medicine: IMP 4.10./2004 "Occupational exposure to ultrafine particles (PM < 10 μm)" as a risk factor for cardiovascular diseases (manager of project: Irena Szadkowska-Stańczyk, prof.) and IMP 20.5 "Return to work after first acute coronary syndrome: The analysis of factors that affect the continuation of occupational activity" (manager of project: Elżbieta Gadzicka, MD, PhD).

StreszczenieWstęp: Względne obciążenie wysiłkiem fizycznym (% VO 2 max) jest ilorazem zapotrzebowania na tlen (VO 2 ) podczas wysiłku fizycznego i maksymalnego poboru tlenu (VO 2 max) przez organizm człowieka, a jego ocena wymaga przeprowadzenia próby wysiłkowej. Względne obciążenie wykazuje wysoką korelację m.in. z wentylacją minutową płuc, pojemnością minutową serca, częstością skurczów serca, objętością wyrzutową lewej komory, zwiększeniem stężenia amin katecholowych we krwi, temperaturą wewnętrzną, masą, wysokością i powierzchnią ciała człowieka. Względne obciążenie stanowi kryterium dopuszczalności obciążenia wysiłkowego w pracy zawodowej ludzi zdrowych i chorych. Poza tym w oparciu o względne obciążenie można dokonać dokładniejszej klasyfikacji wysiłku niż na podstawie wydatku energetycznego. Materiał i metody: W oparciu o własne i światowe dane empiryczne oraz prawa wymiany ciepła i mechanikę płynów opracowano model układu regulacji temperatury wraz z elementami układu krążenia i oddychania. Wykorzystanie tego modelu pozwoliło opracować 2 własne metody wyznaczania względnego obciążenia wysiłkiem fizycznym. Nie wymagają one wykonania próby wysiłkowej, niezbędna jest tylko znajomość temperatury wewnętrznej (T W ) lub częstości skurczów serca w ciągu 1 min (HR) oraz masy (m), wysokości (H) i powierzchni ciała człowieka (A D ). Wyniki: Wartości względnego obciążenia wysiłkiem fizycznym (% VO 2 max) uzyskane za pomocą własnych, nowych metod nie różnią się istotnie statystycznie od średnich wartości uzyskanych innymi metodami przez innych badaczy. Wnioski: Opracowane, nowe metody wyznaczania względnego obciążenia wysiłkiem fizycznym (% VO 2 max) nie wymagają przeprowadzania badań wysiłkowych, dzięki czemu (po zweryfikowaniu w bardziej szczegółowym eksperymencie) mogą być alternatywą dla obecnie stosowanych metod. Med. Pr. 2014;65(2): [189][190][191][192][193][194][195] Słowa kluczowe: obciążenie względne, obciążenie bezwzględne, temperatura wewnętrzna, częstość skurczów serca, klasyfikacja wysiłków fizycznych Abstract Background: The relative physical load (% VO 2 max) is the quotient of oxygen uptake (Vo 2 ) during physical effort and maximum oxygen uptake (VO 2 max) by the human body. For this purpose the stress test must be performed. The relative load shows a high correlation with minute ventilation, cardiac output, heart rate, stroke volume, increased concentrations of catecholamines in the blood, inner temperature, weight, height and human body surface area. The relative load is a criterion for the maximum workloads admissible for healthy and sick workers. Besides, the classification of effort can be more precise when based on the relative load than on the energy output. Material and Methods: Based on our own and international empirical evidence and the laws of heat transfer and fluid mechanics, a model of temperature control system has been developed, involving the elements of human cardiovascular and respiratory systems. Using this model, we have been able to develop our own methods of determining the re...