Assessment of the functional behaviour of precision engineering workers using ultradian rhythms of HRV indicators in the prevention of man-made disasters

. Understanding the functional behavior of precision engineering workers was the aim of studying the ultradian rhythms of HRV indicators to prevent man-made disasters. It was revealed that the higher the voltage of the functional state, the lower the heart rate indicators. The results established specify activation of the vagus associated with cognitive activity. Precision engineers used ultradian rhythms of HRV indicators and the Pareto law to assess the functional behavior of men. The results revealed that work activity negatively impacts the functional behavior and health of 58% of men, placing them in a group associated with human factors and man-made disasters.


Introduction
Understanding the functional behaviour of precision engineering workers was the aim of studying the ultradian rhythms of HRV indicators to prevent man-made disasters.It was revealed that the higher the voltage of the functional state, the lower the heart rate indicators.The results established specify activation of the vagus associated with cognitive activity.Precision engineers used ultradian rhythms of HRV indicators and the Pareto law to assess the functional behaviour of men.The results revealed that work activity negatively affects the functional behaviour and health of 58% of men, placing them in a group associated with human factors and man-made disasters.
Mechanical engineering is a priority and key industry that shows the level of economic development and potential of any country.The high actuality of this study is because the current pace of scientific and technological progress has brought changes to the structure of the mechanical engineering industries.Particular changes have occurred in precision engineering.Modern technology operates on precise and ultra-precise instruments for various purposes.The embedding of nanotechnology requires high attention and precision in the production of technical products.Changes in working conditions in precision engineering have led to biological changes in the body.Which leads to an amount of negative phenomena 1, 2.
Sometimes a person makes mistakes when they are working at the limit of psychophysiological capabilities and in an unfavourable working environment.The "price" of an error in modern production has increased sharply and may be a prerequisite for manmade risks.On most occasion, the erroneous actions of engineers seem unnoticeable, but it was they that sometimes lead to the likelihood of a human factor [3].As a result, there is a need to assess the state of a person performing complex operational tasks that affect his behavior in a production environment [4].
In studies devoted to the problems of man-made risks, a special place is given to the study of the human factor, identifying psychological, physiological and professional components.An important task of such research is the development of recommendations aimed at preventing the occurrence and spread of negative phenomena associated with the high-quality production of a related product, which is a part of a whole product 5, 6, 7.For example, in aircraft accidents, the pilot often blamed for erroneous actions.Whereas the probable cause may be a failure of electronics, as a related product of the finished product.The quality of the product may also depend on the functional state of the manufacturer's body.
The functional state represents a holistic complex of characteristics of human functions and qualities that directly or indirectly determine the implementation of activities [7].The functional state includes the state of the autonomic, nervous, emotional and other systems of the human body.Functional state determines a person's functional behavior and influences the implementation of professional activities.Differences in functional behavior depend on the prevalence of physical and mental stress, levels of professional training, motivation, anxiety, ways of coping with stress, etc. [8,[9][10][11].
Researchers reported that the cardiorespiratory system is most sensitive to environmental influences [8].When solving cognitive problems, attentional tension is associated with a high level of HRV indicators [12][13][14][15].It is observed that people with high HRV are more stressresistant and resistant to environmental changes 16.Performance in operational settings is related to individual differences, anxiety and coping 17-20.Understanding these circumstances or functions of behavior is important when assessing functional behavior.This will allow us to develop corrective recommendations 21-26.
In physiology, there are a series of studies devoted to studying the influence of mental actions on changes in heart rate variability at rest 27 and physical activity.A study of heart rate variability among industrial workers revealed that the subjects' high productivity achieved through the mobilization of physiological resources.28.This is manifested in a change in the level of regulation of the activity of the cardiovascular system; general ergotropic shift of vegetative balance, reducing the variability of cardio intervals and increasing the stress index 28-29.
Professional activities influenced by environmental factors, including atmospheric dust and optical radiation, which can have adverse effects on human health [30].
An analysis of the literature showed that the functional behavior and health of precision engineering workers unsufficiently studied.
The purpose of this study is to evaluate the functional behavior of precision engineering workers by analyzing HRV indicators that follow ultradian rhythms, with the aim of preventing man-made disasters.

Methods
Using of the "Varicard 2.8" hardware and software complex in the "ISCIM6" statistical processing made it possible to study the functional state according to the analysis of heart rate variability.The following indicators of heart rate variability were studied: SI-degree of tension of regulatory systems (stress ); slow fluctuations in harmonic power (HF Hz -total level of activity of the parasympathetic regulation link, LF Hz -total level of activity of the vasomotor center, VLF Hz -total level of activity of the sympathetic regulation link; ULF Hz -total level of activity of the higher autonomic centers; HF% -relative level of activity parasympathetic link of regulation, LF% -relative level of activity of the vasomotor center, VLF % -relative level of activity of the sympathetic regulation link), as well as the dominant periods of frequency components (HFt -respiratory cycle, LFt -baroreflex reaction, VLFt -reflex response of the cardiovascular subcortical center, ULFt -neuroreflex response of subcortical levels of regulation); MxDMn -maximum amplitude of regulatory influences.
The materials were statistically and graphically processed in Microsoft Excel 2003 and "Statistica 11.0" with the calculation of basic statistical indicators (M±m; ±), correlation was determined by Spearman.The analysis gave using Pareto's law, according to which "20% of effort produces 80% of the result."We took the normal values of heart rate variability as 100%.It was assumed that 80% of those examined would meet the result within the normative parameters (for example, the normal limits of the stress index are 70-150), 20% would be below or above the norm).
Forty six male precision engineering workers aged 25-58 years (42.6±1.7;±=11.5)were examined.The indicators recorded in the first half of the working day at rest and performing working movements.Ultradian rhythms (60 minutes) studied at workplaces of a precision machinery industry.

Results
For each of the studied indicators of heart rate variability, three groups of male precision engineering specialists identified with indicators: normal; below normal, above normal.
Analysis of the stress index (SI) showed that 30.4% of the subjects were within the normalized parameters, while 69.6% were above or below the norm.It noted that in 43.6% this indicator individually exceeded the norm by 6 and even 30 times.It can be stated that the identified group is characterized by an adaptation failure (Fig. 1).

Fig. 1. Stress index (SI) indicators for male precision engineering workers in conditions of performing labor movements.
Spectral power indicators also analyzed according to the boundaries of standard parameters.It was revealed that 40.8% of those examined in terms of fast respiratory waves (HF%) were within the normalized limits.This indicator was below or above the norm in 52.2% of those examined.Hypoxia was detected in 30.4% of men during work activities, and hyperoxia in 21.8%.Most men need health examinations in special medical institutions.Since health problems can be the cause of man-made risks (Fig. 2).

Fig. 2. Pareto chart of HF% indicators for men in precision engineering during the research period.
The study of LF% in the slow-wave spectrum, which indicates cardiovascular center activity, showed that 30.4% of men fall within the normalized values.Disturbances in the activity of the cardiovascular center were detected in 69.6%.The normal range is 15-39%, the average in the group was 44.1% ±14.1 (%); ±=2.9, which shows the formation of pathological conditions of the cardiovascular system (Fig. 3).Analysis of ultra-slow waves (VLF%) among male precision engineering workers revealed approximately the same ratio between the boundaries of standard parameters (47.8%) and their violations (52.2%).The average indicator was set within the lower limits of the norm (22.2%±2.9(%); ±-14.2).Ultra-slow waves are associated with the emotional sphere.The results show that 34.8% of men have a deficit in the emotional sphere, considered as a prerequisite for depressive behavior (Fig. 4).Analysis of frequency-spectral components in men in precision engineering revealed the mutual transition of oscillations of frequency-spectral components (HF, LF, VLF, ULF).This show adaptation processes during the period of intense work activity.
Correlation analysis showed a significant level of relationship between the stress index (SI) and the maximum amplitude of regulatory influences (MxDMn) (-0.6; <0.01), SI and VLFt (reflex response of the cardiovascular subcortical center) (-0.6 ; <0.01).The data obtained coincide with the literature that the higher the tension of the functional state, the lower the Baevsky heart rate indicators.

Discussion
We have moved away from the traditional explanation of the data get.And to understand the information received, they chose the poly vagal theory.Its essence lies because vagal activity underlies pro-social tendencies.A priori, work activity can distinguish pro-social.
In the conditions of precision engineering, men perform labor activities in various functional states of the cardiorespiratory system.Physical and mental stress accompanied by an excess or deficiency of neurovegetative functions.According to all studied indicators, in conditions of performing work tasks under the Pareto law, 58% of the surveyed workers have, as a result, a negative impact of production factors on functional behavior.The workers experiencing the negative effects of ongoing production activities could be a techno genie risk group.
The use of methods of coping with stress revealed two groups of men, problem-oriented and emotion-oriented Bashkireva, Eremkin.At a significantly high level, a connection between orientation to the problem and the speed of the neuroreflex response of subcortical levels of regulation (ULFt) in controlling the regulation of heart rhythm was revealed (0.77; P<0.001).This fact can be considered as the influence of the specifics of work actions on the activation of cognitive processes and the dominance of infra-slow waves in the control of heart rhythm regulation.In emotion-oriented men, the vagal link in controlling heart rate regulation significantly increases (0.67; P<0.001).
The received results may indicate vagus activation linked to cognitive activity, supporting the potential explanation of the findings using the polyvagal theory.
Under the Pareto law, 69.6% of men, because of work activity, have prerequisites for disturbances in the control of heart rhythm regulation.The data obtained coincide with the literature that the higher the tension of the functional state, the lower the heart rate indicators.The prerequisites for disturbances in the emotional sphere identified.The use of the technique of coping with stress revealed that in problemoriented men, there was a significantly high correlation with the speed of the neuroreflex response of subcortical levels of regulation (ULFt) in controlling the regulation of heart rhythm.This fact can be considered as the influence of the specifics of work actions on the activation of cognitive processes and the dominance of infra-slow waves in the control of heart rhythm regulation.In men who focused on emotions, the vagal link in controlling the regulation of heart rhythm significantly increases.The results obtained indicate activation of the vagus.What is associated with cognitive activity.Allows the use of poly vagal theory to explain the results obtained.
Thus, an assessment of the functional behavior of male precision engineering workers using ultradian rhythms of HRV indicators using the Pareto law showed that the specifics of work activity negatively affect the functional behavior and health of 58% of the surveyed men, who can be classified as human factors and man-made disasters.

Fig. 3 .
Fig. 3. Pareto chart of LF% indicators for men in precision engineering during the research period.

Fig. 4 .
Fig. 4. Pareto chart of VLF% indicators for men in precision engineering during the research period.