Hemostatic Responses to Multiple Bouts of Firefighting Activity: Female vs. Male Differences in a High Demand, High Performance Occupation

Abstract

While the fire service has long been a male-dominated occupation, women’s participation in this strenuous, high risk, high performance activity has increased in recent years. Firefighting induces significant cardiovascular strain, including hemostatic disruption; however, the effect of sex on hemostatic responses has not been investigated despite evidence that there are sex-related differences in hemostatic variables at rest and following exercise. Thus, we investigated hemostatic responses in age- and BMI-matched male and female firefighters who performed 3–4 evolutions of firefighting drills over a 3 h period. Venous blood samples were collected before and after the firefighting training drills and hemostatic variables were assessed. Firefighting significantly increased platelet count and factor VIII, tissue plasminogen activator (t-PA) antigen, and t-PA activity, and decreased activated partial thromboplastin time and plasminogen activator inhibitor (PAI-1) activity. Females had lower values for epinephrine-induced platelet closure time, antithrombin III, PAI-1 activity, and PAI-1 antigen. There were no interactions between sex and time for any variables assessed. In conclusion, multiple bouts of firefighting activity resulted in a procoagulatory state. Although there were sex differences for several hemostatic variables, male and female firefighters did not differ in their hemostatic response to multiple bouts of firefighting.

The Acute and Chronic Effects of Resistance and Aerobic Exercise in Hemostatic Balance: A Brief Review

“…In contrast to Sackett et al [172], aPTT was decreased on average by more than three seconds (9.0% and 7.7% for females and males), indicating a procoagulatory state for both males and females following firefighting activities [169]. Although there is limited research on women, recent findings indicate no sex-dependent differences in coagulatory response to high-demand activities [169]. However, a recent cross-over study demonstrated distinct sex-specific responses in a 3-month endurance and resistance training plan regarding cardiovascular risk factors [173].…”

“…Interestingly, although fibrinogen decreased significantly in the short-term (four weeks) and increased significantly between four and eight weeks, at the eight-week time point there was no significant difference compared to baseline values [172]. In contrast to Sackett et al [172], aPTT was decreased on average by more than three seconds (9.0% and 7.7% for females and males), indicating a procoagulatory state for both males and females following firefighting activities [169]. Although there is limited research on women, recent findings indicate no sex-dependent differences in coagulatory response to high-demand activities [169].…”

“…Hematologic responses such as plasma volume and blood count (leukocyte, neutrophil, lymphocyte, monocyte, and platelet count) have been investigated, showing that HIIE with longer duration bouts results in a greater post-exercise change in plasma volume, leukocyte, and platelet count [165]. The same tendency has been found in platelet count in healthy adults in response to firefighting drills [169], and in elite karate athletes [170].…”

“…Changes in fibrinolysis caused by exercise are transient, with the return to baseline occurring between 60 min and 24 h following intense activity [179]. In a study by Smith et al [169], multiple bouts of firefighting activity led to increased fibrinolysis (tPA antigen, tPA activity, PAI-1 antigen, PAI-1 activity) in both healthy adult males and females.…”