Physiological Reaction to Work in Cold Microclimate

Abstract

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.

Heart Rate Variability in Occupational Health ―A Systematic Review

“…Long-term occupational exposure to cold environment increases blood pressure in male workers working in cold areas more than once per day 79) . Bortkiewicz et al 34) also found higher blood pressure in workers with exposure to ambient temperatures varying from 0 to 10˚C for 8 h/d than in workers with exposure to ambient temperatures between 10˚C and 14˚C for 8 h/d. However, the chronic effect of occupational exposure to a cold microclimate on HRV was not significant, indicating that HRV might not be a sensitive marker for capturing the adverse effects of exposure to a cold environment on the cardiovascular system.…”

“…Any selected HRV parameters (SDNN and HF, LF, and VLF components) during rest in the morning did not differ between workers who were chronically exposed to different microclimate conditions (-26 to 20˚C) 34) .…”

Impact of climate conditions on hospital admissions for subcategories of cardiovascular diseases

“…Because of the computer databases used for the health data, we were not able to consider all of the risk factors for the CVD, like smoking status, alcohol consumption, obesity, physical activity and socioeconomic status. Because of the age specific results in this study, with the vision of defining the most vulnerable population, it might have been advisable to define more than 2 age groups (e.g., 25-35 years old, 36-55 years old, or > 80 years old) as well as gender specific groups according to the results of some other authors [33]. The use of the hospital admissions as health data does not represent the real state of morbidity, too because some cases were linked only to medical examination, without admission.…”

Thermal stress, human performance, and physical employment standards

“…No significant differences between the different categories of working temperatures were observed. The large variation in metabolic rate was due to significant differences between work shift durations, varying from approximately 5 to 18 h (Bortkiewicz et al 2006). In the study of Kluth et al (2012), HR rose above the resting level in senior workers (aged 40-65 years) by ϳ30 beats·min −1 and in younger workers (aged 20-35 years) by ϳ35 beats·min −1 .…”