The Effects of Oxygen Enriched Air on Firefighter Job Performance

By Bernard E. Williams, Ph.D.

When using SCBA, firefighters are able to get to the seed of a fire more quickly, and are able to perform rescue, ventilation, suppression, and salvage and overhaul functions without breathing in toxic smoke and gases. A problem associated with the use of SCBA is that under heavy work loads, such as rescue maneuvers, stair climbing with equipment, and forcible entry, the rate of air flow from the regulator has the potential to limit the physical performance of firefighters.

The purpose of this research was to examine the potential for improving the operating efficiency of SCBA. Specifically, this research examined the use of oxygen- enriched (hyperoxic) air as a method of increasing the ability of firefighters to perform physically demanding tasks while using SCBA.

This research adopted an experimental research design in order to test the following hypotheses:

H1. The heart rate responses under the hyperoxia conditions will be lower than heart rates under the normox conditions.

H2. The blood lactate levels under the hyperoxia conditions will be lower than the blood lactate levels under the normox conditions.

H3. The perceived physical exertion under the hyperoxia conditions will be lower than perceived physical exertion under the normox conditions.

H4. The times on each individual event under the hyperoxia conditions will be lower than the event times under the normox conditions.

H5. The total elapsed times under hyperoxia conditions will be lower than the total elapsed times under normox conditions.

The procedures used to test these hypotheses involved a double-blind within-subjects design. During different trials in the study, 17 subjects completed a number of evolutions involving a series of simulated firefighting tasks. Subjects were randomly assigned SCBA that contained either normal breathing air (normoxic) or oxygen-enriched air (hyperoxic). Performance measures and physiological data were collected under the two different experimental conditions and the data were analyzed in order to test the hypotheses.

The results of the study provided support for H3, H4, and H5, however H1 and H2 were rejected. In rejecting H1 and H2, the researchers noted that although heart rate and blood lactate levels were similar under the two conditions (normoxic and hyperoxic) the reduction in times to complete the tasks indicated a higher level of work output at similar heart rates and lactate levels.

The results of the study provide strong support for the positive effects of hyperoxia on the performance of firefighters, and suggest the need for further research. Four recommendations for further research were proposed, including a recommendation to seek corporate and/or government funding to support further research.