This study describes the effects of strenuous live-fire fire fighting drills and 90min of recovery on hematological and psychological variables. Eleven fire fighters performed three trials of fire fighting tasks in a training structure that contained live fires. Plasma volume decreased immediately following the drill, but returned to baseline following recovery and aggressive rehydration. Blood glucose and sodium concentrations were significantly lower than pre-test, or immediately post-fire fighting values, after recovery. Perceptual variables all increased during fire fighting activities. These data emphasize the need for aggressive fluid replacement following fire fighting activity, and indicate that carbohydrate/electrolyte replacement may be beneficial prior to subsequent activity.