Introduction. Currently, there is an increasing need for the study and development of the World Ocean, including for the purpose of laying deep-water pipelines, searching for new sources of minerals, etc. The performance of special tasks by divers at great depths has its own characteristics. The high cost of error, harmful working conditions — all this dictate the need for continuous receipt and analysis of scientific material on the preservation and promotion of health, ensuring their longevity, as well as the adaptation of divers to the nature and conditions of professional activity in order to prevent the occurrence of errors.

The study aims to explore the functions of attention and thinking of a person, his fine muscular coordination and subjective assessment of the state of the body of divers, as elements of the functional state of the body, when working underwater.

Materials and methods. We examined 18 divers, divided into two groups: the first — ten people made daily descents to a depth of 18 m, the second group — eight people dived to a depth of 56 m. Before and after diving, the divers underwent a psychophysiological examination to assess the function of attention (the method of the correction test with Landolt rings), the function of thinking (the method of the arithmetic test "addition in mind"), fine muscle coordination (the method of macrography) and subjective assessment of the state (the SAN questionnaire (state of health — activity-mood)).

Results. During diving operations, there was a decrease in subjective self-assessment of the state of the body (SAN test), an increase in the number of errors (correction test with Landolt rings — attention function) and the values of the height index of numbers (macrography technique — fine muscle coordination), a decrease in the speed of thinking depending on the depth, the multiplicity of diving descents, as well as the dive itself (regardless from depth and multiplicity) on the functional state of divers. There were most pronounced changes during prolonged work (3–5 days or more) and when diving to a depth of 56 m.

Conclusion. The dynamics of objective indicators and subjective assessment of the state of the body indicates that with an increase in the depth of immersion (from 18 to 56 m), the multiplicity of diving descents (daily immersion for 5 days) and the dive itself, the self-esteem of the state, the speed of thinking, attention, fine muscle coordination decreases.

Ethics. The study was conducted in compliance with the Ethical principles of conducting medical research with human participation as a subject, set out in the Helsinki Declaration of the World Medical Association.

Contribution:Zverev D.P. — research concept and design, data collection and processing, writing the text, text editing;Klenkov I.R. — research concept and design, data collection and processing, writing the text, text editing;Myasnikov A.A. — research concept and design, data collection and processing, writing the text, text editing;Fateev I.V. — research concept and design, data collection and processing, writing the text, text editing;Bychkov S.A. — research concept and design, data collection and processing, writing the text, text editing;Mavrenkov E.M. — research concept and design, data collection and processing, writing the text, text editing;Vetryakov O.V. — research concept and design, data collection and processing, writing the text, text editing;Minnullin T.I. — writing the text, text editing.

Acknowledgment. The authors express their gratitude to the Underwater Research Center of the Russian Geographical Society represented by Executive Director Sergey Georgievich Fokin for the opportunity to conduct research.

Funding. The study had no funding.

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

 Received: 07.02.2022 / Accepted: 21.07.2022 / Published: 15.08.2022