Long-term strenuous exercise induces a hypercoagulable state through contact activation

Management of venous thromboembolism in athletes

Venous thromboembolism (VTE) is a common condition with high associated morbidity and mortality. Athletes have unique VTE risk factors compared with the general population, and may have a higher than anticipated risk of thrombosis. Anticoagulant treatment poses additional challenges in athletes, as these individuals usually wish to return to sporting activities without delay. In addition, those athletes who engage in contact sports may have bleeding complications with extended anticoagulation. In this paper, we discuss VTE risk factors in athletes, the impact of exertion on haemostasis, measures which could be adopted to mitigate VTE risks in these highly active individuals and options to deal with bleeding risks from anticoagulation during injury-prone sporting activities.

Additive effect of erythropoietin use on exercise-induced endothelial activation and hypercoagulability in athletes

Purpose

Recombinant human erythropoietin (rHuEPO) is known to increase thrombotic risk in patients and might have similar effects in athletes abusing the drug. rHuEPO is prohibited by anti-doping legislation, but this risk has not been investigated thoroughly. This analysis was designed to evaluate whether rHuEPO impacts hemostatic profile and endothelial and platelet activation markers in trained subjects, and whether the combination with exercise affects exercise induced alterations.

Methods

This double-blind, randomized, placebo-controlled trial enrolled healthy, trained male cyclists aged 18–50 years. Participants were randomly allocated (1:1) to receive subcutaneous injections of rHuEPO (epoetin-β; mean dose 6000 IU per week) or placebo (0.9% NaCl) for 8 weeks. Subjects performed five maximal exercise tests and a road race, coagulation and endothelial/platelet markers were measured at rest and directly after each exercise effort.

Results

rHuEPO increased P-selectin (+ 7.8% (1.5–14.5), p = 0.02) and E-selectin (+ 8.6% (2.0–15.7), p = 0.01) levels at rest. Maximal exercise tests significantly influenced all measured coagulation and endothelial/platelet markers, and in the rHuEPO group maximal exercise tests led to 15.3% ((7.0–24.3%), p = 0.0004) higher E-selectin and 32.1% ((4.6–66.8%), p = 0.0207) higher Platelet factor 4 (PF4) levels compared to the placebo group.

Conclusion

In conclusion, rHuEPO treatment resulted in elevated E- and P-selectin levels in trained cyclists, indicating enhanced endothelial activation and/or platelet reactivity. Exercise itself induces hypercoagulability, and the combination of rHuEPO and exercise increased E-selectin and PF4 levels more than either intervention alone. Based on this, exercise potentially increases thrombotic risk, a risk that might be enhanced in combination with rHuEPO use.

Electronic supplementary material

The online version of this article (10.1007/s00421-020-04419-0) contains supplementary material, which is available to authorized users.

Platelet Aggregation in Healthy Participants is Not Affected by Smoking, Drinking Coffee, Consuming a High-Fat Meal, or Performing Physical Exercise

Platelet aggregation can be measured using optical aggregation (light transmission aggregometry, LTA) as well as by impedance (Multiplate analyzer). The LTA (the gold standard method) can be influenced by many preanalytical variables. Several guidelines differ in recommendations for the duration patients should refrain from smoking, coffee, fatty meals, and physical exercise prior to blood collection for performing platelet function tests. In this pilot study, the influence of smoking, coffee, high-fat meal, or physical exercise on platelet aggregation was investigated to improve patient friendliness and laboratory logistics in platelet function diagnostics. Standardized blood collection was performed when participants were fasting and after each parameter (n=5 per group). As a control for diurnal fluctuations, participants (n=6) were fasting during both blood collections. Platelet aggregation was executed using standardized methods for LTA and Multiplate analyzer. Statistical analysis of the results using Wilcoxon signed-rank test did not show any significant differences in platelet aggregation in healthy participants under different preanalytical variables. Therefore, these variables are not expected to adversely affect testing, which can avoid canceling tests for those patients who inevitably did.

Effects of 6 Months of Active Commuting and Leisure-Time Exercise on Fibrin Turnover in Sedentary Individuals with Overweight and Obesity: A Randomised Controlled Trial

Obesity and exercise constitute important factors for cardiovascular disease risk, but the long-term effects of different exercise modalities on haemostatic biomarkers are not well elucidated. We investigated the effects of 6 months of active commuting or leisure-time exercise on measures of fibrin turnover in individuals who are overweight and obese. Ninety younger (20-40 years), sedentary, healthy women and men who are overweight and obese (BMI: 25-35 kg/m²) were randomised to 6 months of habitual lifestyle (CON, n=16), active commuting (BIKE, n=19), or leisure-time exercise of moderate (MOD, ∼50% VO₂peak reserve, n=31) or vigorous intensity (VIG, ∼70% VO₂peak reserve, n=24). Fasting blood samples (baseline and 3 and 6 months) were analysed for cholesterols and triglycerides, thrombin generation, prothrombin fragment 1 + 2, D-dimer, fibrin clot properties, and fibrinolytic activity. We observed no differences between CON, BIKE, MOD, and VIG during the intervention and no time effects for any of the variables measured despite increased VO₂peak in all exercise groups. We found no difference between CON and all exercise groups combined and no gender-specific effects of exercise. Our findings suggest that thrombin generation capacity, coagulation activation, fibrin clot structure, and lysability are unaffected by long-term active commuting and leisure-time exercise in women and men who are overweight and obese.

Strenuous exercise induces a hyperreactive rebalanced haemostatic state that is more pronounced in men

Physical exercise is recommended for a healthy lifestyle. Strenuous exercise, however, may trigger the haemostatic system, increasing the risk of vascular thrombotic events and the incidence of primary cardiac arrest. Our goal was to study the effects of strenuous exercise on risk factors of cardiovascular disease. Blood was collected from 92 healthy volunteers who participated in the amateur version of the pro-tour Amstel Gold cycling race, before and directly after the race. Thrombin generation showed a shortening of the lag time and time to peak and an increase of the velocity index. Interestingly, the endogenous thrombin potential measured in plasma decreased due to reduced prothrombin conversion. Platelet reactivity increased and this effect was stronger in men than in women. Lower fibrinogen and higher D-dimer levels after exercise indicated higher fibrin formation. On the other hand, fibrinolysis was also elevated as indicated by a shortening of the clot lysis time. Exercise activated the endothelium (von Willebrand factor (VWF) and active VWF levels were elevated) and the immune system (concentrations IL-6, IL-8, MCP-1, RANTES and PDGF increased). Additionally, an increased cardiac troponin T level was measured post-exercise. Strenuous exercise induces a temporary hyperreactive state in the body with enhanced pro- and anticoagulant responses. As strenuous exercise has a more pronounced effect on platelet function in male subjects, this gives a possible explanation for the higher incidence of sudden cardiac death during exercise compared to women. This trial is registered at www.clinicaltrials.gov as NCT02048462.

Neutrophil extracellular traps: a walk on the wild side of exercise immunology

Intense exercise evokes a rapid and transient increase in circulating cell-free DNA (cf-DNA), a phenomenon that is commonly observed in a variety of acute and chronic inflammatory conditions. While the potential value of cf-DNA for the prediction of disease outcome and therapeutic response is well documented, the release mechanisms and biological relevance of cf-DNA have long remained enigmatic. The discovery of neutrophil extracellular traps (NETs) provided a novel mechanistic explanation for increased cf-DNA levels. Now there is increasing evidence that NETs may contribute to cf-DNA in diverse infectious, non-infectious and autoinflammatory conditions, as well as in response to acute exercise. NETs have now been firmly established as a fundamental immune mechanism used by neutrophils to respond to infection and tissue injury. On the other side, aberrant formation of NETs appears to be a driving force in the pathogenesis of autoimmunity and cardiovascular disease. Thus, the emergence of NETs in the 'exercising vasculature' raises important questions considering beneficial effects, as well as occasional adverse effects, of exercise on immune homeostasis. This review gives an overview of the current state of research into the mechanisms of how NETs are released, contribute to host defence and participate in inflammatory disorders. We discuss the impact of exercise-induced NETs, considering a potentially beneficial role in the prevention of lifestyle-related diseases, as well as putative detrimental effects that may arise in elite sports. Finally, we propose that exercise-induced cf-DNA responses could be exploited for diagnostic/prognostic purposes to identify individuals who are at increased risk of cardiovascular events or autoimmunity.