Biomarker and Biometric Indices of Physical Exhaustion in the Firefighting Community

Firefighters are three times more likely to die on the job than any other occupation with half of these deaths due to heart attacks, stroke, or heat exhaustion from stress and over exertion [1] . Most protection of firefighters is focused on gear and equipment. Our objective is to test biomarkers and biometrics of high physical exertion in the laboratory and the field to discover irregular patterns of physiological or biological responses in order to save lives. Twenty firefighters between the ages of 22-57 participated in 5 sessions of testing. Session 1 provided baseline fitness levels with a VO2 Maximal Treadmill test and DEXA body composition scan. Session 2 utilized a Modified Astrand Treadmill protocol with participants wearing full firefighter gear minus the mask. Session 3 was the Firefighter Combat Challenge simulation. Session 4 was a live fire evolution in their training building. Finally, Session 5 repeated session 2 with the addition of a cooling vest worn under the gear. Results showed for biomarker indices of physical exhaustion that lactate and serotonin significantly increased immediately following physical exhaustion while cortisol and DHEAS significantly increased 10 minutes following the exhaustion. Some biophysiological patterns were also found. We also found some biological recovery patterns. Serotonin and orexin-A have opposing trends from post physical exhaustion to 10 minutes post physical exhaustion. Cortisol and DHEAS have opposing trends between the two blood draws as well. These results can help drive the innovation for real-time biosensors to diagnose and analyze physiological and cognitive health for firefighters.