Heart rate and ECG responses of fire fighters.

Data were obtained from 35 fire fighters responding to 189 alarms. Fifteen to 30 sec after an alarm heart rate showed a mean increase of 47 beats/min (range 12-117 beats/min). Approximately one minute after the alarm, while on the truck, heart rate still showed a mean increase of 30 beats/min (range 1 to 80 beats/min) above that recorded before alarm. S-T segment changes were observed in the ECG shortly after the alarm sounded. Upon approaching a fire, heart rates as high as 150 beats/min were observed before the men got off the fire truck. During actual fire fighting extremely high heart rates were observed for prolonged periods of time. One fire fighter had a mean heart rate of 188 beats/min for 15 minutes during the initial stages of a structure fire. The heart rate responses observed immediately after the alarm as well as on the truck approaching a fire indicate that the men experience a state of high anxiety. The extremely high heart rates observed for prolonged periods during fire fighting may also indicate a state of high anxiety coupled with the heavy work performed in a hot environment. Repeated exposure to states of high anxiety as well as inhaling pollutants related to the high incidence of ischemic-stress tests previously observed in fire fighters.