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Clotting and Fibrinolytic Changes after Firefighting Activities


Medicine & Science in Sports & Exercise: March 2014 - Volume 46 - Issue 3 - p 448–454
doi: 10.1249/MSS.0b013e3182a76dd2
Clinical Sciences

Approximately 45%–50% of all duty-related deaths among firefighters are due to sudden cardiovascular events, and a disproportionate number of these fatalities occur after strenuous fire suppression activities.

Purpose: The objective of this study is to evaluate the effect of strenuous firefighting activities on platelets, coagulation, and fibrinolytic activity and to document the extent to which these variables recovered 2 h after completion of the firefighting activity.

Methods: Firefighters performed 18 min of simulated firefighting activities in a training structure that contained live fires. After firefighting activities, firefighters were provided with fluid and allowed to cool down and then recovered for 2 h in an adjacent room. Blood samples were obtained prefirefighting, postfirefighting, and 2 h postfirefighting.

Results: Platelet number, platelet activity, and coagulatory potential increased immediately postfirefighting and many variables (platelet function, partial thromboplastin time, and factor VIII) reflected a procoagulatory state even after 2 h of recovery. Fibrinolysis, as reflected by tissue plasminogen activator, also was enhanced immediately postfirefighting but returned to baseline values by 2 h postfirefighting. In contrast, inhibition of fibrinolysis, as evidenced by a reduction in plasminogen activator inhibitor-1, was depressed at 2 h postfirefighting.

Conclusions: Firefighting resulted in elevated coagulatory and fibrinolytic activity. However, 2 h postfirefighting, tissue plasminogen activator returned to baseline and coagulatory potential remained elevated. The procoagulatory state that exists after firefighting may provide a mechanistic link to the reports of sudden cardiac events after strenuous fire suppression activities.

1Illinois Fire Service Institute, University of Illinois Urbana-Champaign, Champaign, IL; 2Department of Health and Exercise Sciences, Skidmore College, Saratoga Springs, NY; 3Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL; 4Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL; and 5Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, IL

Address for correspondence: Denise L. Smith, Ph.D., Department of Health and Exercise Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY 12866; E-mail:

Submitted for publication January 2013.

Accepted for publication July 2013.

© 2014 American College of Sports Medicine