An evaluation of physiological demands and comfort between the use of conventional and lightweight self-contained breathing apparatus.

The additional physiological strain associated with the use of self-contained breathing apparatus (SCBA) is mostly linked to the additional weight. Lightweight and conventional SCBA were assessed in a submaximal step test performed in full firekit (total weights 15 and 27 kg, respectively). Factors assessed were: comparative energy expenditure of the two sets, relationship between comparative energy expenditure and aerobic fitness and subjective discomfort. Measured variables were: oxygen consumption, heart rate, estimated VO2max and subjective discomfort (body part discomfort scale). The lightweight SCBA displayed a significant oxygen consumption benefit, which was independent of dynamic workrate and valued at 0.2561 min(-1). Mean heart rate responses were significantly lower with the light set. No relationship was found between comparative energy expenditure and aerobic fitness. The light set was rated as significantly more comfortable than the heavy. Further research is required to assess the extent of the energy consumption benefit in realistic fire suppression protocols and the contribution of ergonomic factors to the energy and comfort benefits.