Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Date of Award

Spring 2017

Document Type


Degree Name

Master of Science (MS)


Department of Kinesiology


Christopher Joseph Womack

Elizabeth Skidmore Edwards

Michael J. Saunders


Sudden cardiac events are the leading cause of death among firefighters, and it is acknowledged that most ischemic events are due to an occlusive thrombus formation. In addition, due to the demanding job requirements and shift work, firefighters commonly overuse caffeine. The purpose of this study was to examine the potential effects of caffeine on the hemostatic response to simulated firefighting activity. Twelve healthy male firefighters (age, 31.3 ± 5.4 yrs; weight, 94.2 ± 13.1 kg; BMI, 28.7 ± 2.9 kg·m-2) participated in this study, wearing full personal protective equipment (PPE) and self-contained breathing apparatus (SCBA). Subjects completed two trials of a simulated firefighting activities course after consuming either 6mg/kg BW of caffeine or placebo one hour prior to exercise. Blood samples and air levels from the SCBA were obtained pre-exercise and post-exercise, and time to completion was recorded. Factor VIII and tissue plasminogen activator (tPA) activity increased post-exercise and plasminogen activator inhibitor-1 (PAI-1) activity decreased post-exercise in both conditions. There was a significant treatment x exercise interaction for Factor VIII levels as they increased more in the caffeine trial. There was a trend (p = 0.05) for increased air consumption in the caffeine condition versus placebo condition. Results from the present study suggest that caffeine elicits a higher coagulation response without concomitant increases in fibrinolysis during simulated firefighting.