Features of the long-term dynamics of heart rate variability among workers of a potash ore processing enterprise
Authors: Nosov Alexandr E. , Zaitseva Nina V. , Kostarev Vitalii G. , Ivashova Julia A. , Savinkov Maksim A. , Ustinova Olga Yu. 
Published: September 2021

Introduction. Currently, the violation of heart rate variability as one of the main pathogenetic mechanisms of the damaging effect of pollutants, associated effects on the cardiovascular system. The study aims to explore the dynamics of the influence of the autonomic nervous system (ANS) on heart rate variability (HRV) in workers of a potassium ore processing enterprise exposed to industrial pollutants (fine fractions of potassium chloride dust, formaldehyde, hexane, heptane) with an assessment of changes in dependence from work experience, establishment of cause-and-effect relationships of violations of heart rate variability with exposure to chemical compounds. Materials and methods. The object of the study was 140 employees of a potash ore processing enterprise, assigned to the observation group, and 76 employees of the administrative and technical apparatus, who made up the comparison group. Samples were taken from the air of the working medium for the content of saturated hydrocarbons (hexane, heptane), the vapors of formhehyde were considered, and the presence of fine particles PM2.5 and PM10 was established. Investigation of biological media (blood, urine) of workers at the enterprise determination of formaldehyde in blood, hexane and heptane in urine. Evaluation of heart rate variability was carried out on a computer electrocardiograph "Poli-Spectr-8/EX" using a cardiorhythmographic program using the method of time analysis, variation pulsometry and spectral analysis. Results. The concentration of fine particles in the air at the workplaces of the observation group was 12-111 times higher for PM2.5, and 5.6-74.6 times higher for PM10 than for the work places of the comparison group. The concentration of formaldehyde, hexane and heptane in the air did not exceed hygienic standards. In the observation group relative to the comparison group, formaldehyde blood was 1.5 times (p<0.001), in the urine of hexane - 1.2 times (p=0.011), heptane - 1.3 times (p=0.046). It was found that with an experience of up to 10 years, formaldehyde in the blood of workers in the observation group was 1.4 times higher than that in the comparison group (p=0.011), with an experience of more than 10 years - 1.7 times (p=0.005). In the urine of workers in the observation group with work experience of up to 10 years, an excess of 1.3 (p=0.026) relative to the comparison group of hexane was found. HRV data analysis. With damage to the length of service in the observation group, there was a significant decrease in the temporal analysis indicators (SDNN, ms, RMSSD, ms, pNN50, %, CV, %), while in the comparison group, only the CV, % decrease was statistically significant; the values of IN conventional units, AMo, % significantly increased (p=0.03 and p=0.003, respectively). A statistically significant relationship was established between the likelihood of an increase depending on the content of heptane in urine (b0=0.22; b1=10.6; F=21.5; R2=0.09; p=0.0001) and formaldehyde in the blood (b0=0.02; b1=6.55; F=69.6; R2=0.25; p=0.0001) in the surveyed workers. Conclusions. Activation of central ergotropic and humoral-metabolic mechanisms, a tendency towards a decrease in parasympathetic influences. The method of logistic regression analysis established a statistically significant relationship between the probability of an increase in the stress index depending on the heptane content in the blood of the surveyed suppliers.