Assessment of firefighters-rescuers' work severity in relation with interaction between physical and mental load

The present work is focused on occupational health problems caused by ergonomic risk in firefighting, which is one of the most hazardous occupations. The aim was to evaluate the work heaviness degree and to estimate the muscle fatigue for a study group consisting of 12 firefighters-rescuers. Applying qualitative ergonomic analyses (OWAS a.o.) and clinical experiments to determine consumed metabolic energy using heart rate monitoring, the following work hardness categories were observed: firefighter-rescuer — category III (hard work, 8.2 ± 1.2 kcal/min); commanding officers — category II (moderate work, 6.0 ± 1.6 kcal/min). Assessment of muscle strain and functional state (tone) using myotonometric measurements showed several muscle tone levels, allowing subdivision of firefighters into different conditional categories basing on muscle tone and fatigue: I — a state of equilibrium when muscles are able to adapt to the work load and are partly able to relax; and II — muscle fatigue and increased tone. It was also found that the increase of muscle tone and fatigue mainly depended on workers physical preparedness and length of service, and less on their age. Assessment interaction of mental and physical load using NASA-TLX method indicated that the highest degree of total workload was for several firemen, especially, commanding officers when temporary demands, task performance, effort and frustration were taken into consideration. Šaj _ darb _ pētītas ugunsdzēsēju - gl _bēju arodveselības problēmas saistīb _ ar ergonomiskiem riskiem. Pētījuma mērķis bija noteikt darba smaguma pak _pi un novērtēt muskuļu nogurumu fizisk _ un garīg _ darba mijiedarbības rezult _t _ 12 ugunsdzēsējiem, kuri str _d _ vien _ komand _. Pētījum _ lietotas kvalitatīv _s ergonomisk _s analīzes metodes (OWAS u.c.) un veikti klīniskie pētījumi: sirds ritma monitorings, lai izvērtētu darba proces _ patērēto metabolisko energiju, un miotonometrisko mērījumu analīze, lai noteiktu muskuļu tonusu un izvērtētu to noguruma pak _pi. Pēc sirdsdarbības ritma monitoringa datiem noteiktas vair _kas darba smaguma kategorijas: ugunsdzēsējiem - gl _bējiem - III kategorija (smags darbs, 8,2 ± 1,2 kcal/min); ugunsdzēsēju komandieriem - II kategorija (vidēji smags darbs, 6,0 ± 1,6 kcal/min). Analizējot muskuļu spriedzi un to funkcion _lo st _vokli (tonusu), lietojot miotonometrijas metodi, noteiktas š _das muskuļu tonusa un noguruma kategorijas: I - līdzsvara st _voklis, kad muskuļi spēj piel _goties darba