Classification of metabolic and respiratory demands in fire fighting activity with extreme workloads.

Fire fighting work comprises work tasks requiring an energy yield at maximal or close to maximal levels of the individual. Due to the very nature of fire fighting more complex physiological variables are difficult to measure. We measured metabolic and respiratory responses in 15 male, professional fire fighters during simulated work tasks on a test ground. Work time was on the average 22 min with individual components of work tasks lasting 2-4 min. The mean oxygen consumption for the whole exercise (22 min) was 2.75+/-0.29 l/min. The most demanding work task demanded an oxygen uptake of 3.55+/-0.27 l/min. Corresponding values for respiratory minute volumes were 82+/-14 and 102+/-14l/min, respectively. Heart rates averaged 168+/-12 for the whole test and 179+/-13 beats/min for the heaviest work task. Two new classes for classification of intensive and exhausting, short term physical work are proposed for inclusion in ISO8996 and values for relevant parameters are proposed.