The duration of work-related fatigue as a criterion for assessing the workload and the cause of chronic diseases of workers

Introduction. The developers of fatigue risk management systems in the workplace note that there is no universal definition and a consistent way to measure workload, and that scientists have not sufficiently studied the relationship between workload and fatigue.

The study aims to analyze the impact of the workload, estimated by the duration of the state of production-related fatigue of workers, on their subjective health and the risk of chronic diseases.

Materials and methods. The study involved employees in three areas of employment: healthcare (697 employees), industry (751), education (687). Experts have determined four indicators of the risk of violation of the subjective health of employees during the year: the presence of chronic fatigue syndrome (R_cfs), deterioration of employee health during the year (R_dh), long-term illnesses during the year (R_li), fatigue accumulation during the year (R_fa). We have analyzed the diseases detected during periodic medical examination. The researchers have calculated the HFweek indicator — the duration of the fatigue state — "hours of fatigue per working week": HF_week (hour) = PRN (hour) × K_df × K_ff, where: PRN (hour) is the actual duration of the working week; Kdf and Kff are coefficients that take into account the degree and frequency of fatigue. We also have calculated the relative risk (RR).

Results. The researchers have found that with more than 25 hours per week in 108 sample groups of workers in 25 cases, RR exceeded the control level by more than 5 times; in 44 comparison groups by 2.1–5 times and in 35 groups by 1.1–2.0 times. 

With a HF_week of more than 25 hours, there is an annual accumulation of fatigue (R_fa), similar in workers of all spheres of employment. At HF_week>15 hours, the RR of chronic diseases of the musculoskeletal, respiratory, nervous systems and skin was in the range of 1.31–1.83. The RR of diseases of the genitourinary system (women) and endocrine system increased by 1.13 times; diseases of hypertension, diseases of the digestive system, visual system RR÷1,05–1,07.

Conclusion. The HFweek indicator is the physiological equivalent of the professional workload of employees in various fields of employment. With HFweek>25 hours, there is a sharp increase in health risks.

Contribution:
Sorokin G.A. — concept and design of the study, responsibility for the integrity of all parts of the article, collection of literature data, statistical processing, writing the text;
Chistyakov N.D. — collection of observation materials.

Funding. The study had no funding.

Conflict of interests. The authors declare no conflict of interests.

Received: 30.09.2022 / Accepted: 03.10.2022 / Published: 23.10.2022

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