Sothmann et al. (1992) had 10 firefighters wear heart rate monitors and oxygen consumption equipment while responding to actual fires. Lab testing to determine HR max and max VO2 had previously been completed. It was found that during an emergency, the firefighters worked at 88% of max HR for 15 minutes with a VO2 of 25.6ml/kg/min. This indicates that the target VO2max of 42ml/kg/min of most fire departments is well within reason in constructing fitness programs for firefighters.