Evaluation of clotting and fibrinolytic activation after protracted physical exercise

Dynamic Metabolic Response, Clotting Times and Peripheral Indices of Central Fatigue in Horse Competing in a 44 Km Endurance Race

A deep knowledge on metabolic response of athlete horse to exercise is of paramount importance for the development of optimal training programs to attain equilibrium between good performance and animal welfare. This study investigated the dynamic change of metabolic, clotting times and peripheral indices of central fatigue in horses competing in an official 44 km endurance race.  From 6 horses blood samples were collected at rest (T_PRE), within 5 minutes from the end of race (T_PE5), after 30, 60 minutes after the end of race (T_PE30 and T_PE60) to investigate the values of blood lactate, glucose, platelets (PLTs), serum leucine, isoleucine, valine, tryptophan, the ratio between tryptophan and branched-chain amino acids (BCAAs) levels (Try/BCAAs), total proteins, non-esterified fatty acids, plasma thrombin time (TT), prothrombin time (PT), activated partial thromboplastin time and fibrinogen (Fb). Lactate, PLTs, non-esterified fatty acids, BCAAs and Try/BCAAs showed higher values at T_PE5, T_PE30and T_PE60than T_PRE(P < .0001); glucose showed lower values at T_PE5, T_PE30and T_PE60than T_PRE(P < .0001). Higher TT values were found at T_PE5, T_PE30and T_PE60than T_PRE, and at T_PE5than T_PE30 and T_PE60(P < .0001); Fb was higher at T_PE5than T_PRE, T _PE30and T_PE60(P < .0001). This survey confirms that horses performing prolonged physical exercise experienced glycolysis, lipid mobilization and amino acid metabolism to provide substrates as fuel for muscle contraction.

Coronavirus (COVID-19), Coagulation, and Exercise: Interactions That May Influence Health Outcomes

The proinflammatory cytokine storm associated with coronavirus disease 2019 (COVID-19) negatively affects the hematological system, leading to coagulation activation and endothelial dysfunction and thereby increasing the risk of venous and arterial thrombosis. Coagulopathy has been reported as associated with mortality in people with COVID-19 and is partially reflected by enhanced D-dimer levels. Poor vascular health, which is associated with the cardiometabolic health conditions frequently reported in people with severer forms of COVID-19, might exacerbate the risk of coagulopathy and mortality. Sedentary lifestyles might also contribute to the development of coagulopathy, and physical activity participation has been inherently lowered due to at-home regulations established to slow the spread of this highly infectious disease. It is possible that COVID-19, coagulation, and reduced physical activity may contribute to generate a “perfect storm,” where each fuels the other and potentially increases mortality risk. Several pharmaceutical agents are being explored to treat COVID-19, but potential negative consequences are associated with their use. Exercise is known to mitigate many of the identified side effects from the pharmaceutical agents being trialled but has not yet been considered as part of management for COVID-19. From the limited available evidence in people with cardiometabolic health conditions, low- to moderate-intensity exercise might have the potential to positively influence biochemical markers of coagulopathy, whereas high-intensity exercise is likely to increase thrombotic risk. Therefore, low- to moderate-intensity exercise could be an adjuvant therapy for people with mild-to-moderate COVID-19 and reduce the risk of developing severe symptoms of illness that are associated with enhanced mortality.

Venous thromboemboli associated with acute aerobic exercise: A review of case report commonalities

Venous thromboembolic (VTE) events such as deep vein thrombosis (DVT) and pulmonary embolism (PE) have been reported in otherwise low-risk healthy athletes following acute bouts of aerobic exercise.

PURPOSE

To review case reports and assess the commonalities of athletic individuals with VTE, as well as return-to-play (RTP) recommendations.

METHODS

We reviewed 47 reports (20 DVTs, 15 PEs, and 12 DVTs/PEs, 19 women) of trained individuals who were diagnosed with DVT and/or PE following aerobic exercise. We assessed frequency of VTE risk factors, presenting symptoms, and RTP recommendations.

RESULTS

The age of women (24.6 ± 7.0 years) was lower (P < .01) than of men (40.6 ± 13.6 years). Of the 19 women, 14 (73.7%) used oral contraceptives. Thirteen cases (27.7%) reported a recent period of prolonged inactivity (>1 hour), and another 12 cases were found to have an antithrombin disorder following testing after diagnosis. The most frequently reported symptoms were muscle pain in 26 of 32 (81.3%) DVT or DVT/PE cases, and dyspnea in 21 of 27 (77.8%) PE or DVT/PE cases. Despite these common symptoms, the estimated time from first report of symptoms to confirmed diagnosis was 56.3 ± 118.7 days and 25 cases (53.2%) were initially misdiagnosed. Twenty-three cases (48.9%) did not report RTP recommendations, and those which did varied widely.

CONCLUSIONS

Thirty-two cases (~70%) had at least one of three major risk factors, suggesting that many cases of VTE in athletes may be preventable with better education and awareness. The wide variety of RTP recommendations highlights the need for standardized guidelines in this population.

Compression socks and the effects on coagulation and fibrinolytic activation during marathon running

PURPOSE

Compression socks are frequently used in the treatment and prevention of lower-limb pathologies; however, when combined with endurance-based exercise, the impact of compression socks on haemostatic activation remains unclear.

OBJECTIVES

To investigate the effect of wearing compression socks on coagulation and fibrinolysis following a marathon.

METHODS

Sixty-seven participants [43 males (mean ± SD: age: 46.7 ± 10.3 year) and 24 females (age: 40.0 ± 11.0 year)] were allocated into a compression (SOCK, n = 34) or control (CONTROL, n = 33) group. Venous blood samples were obtained 24 h prior to and immediately POST-marathon, and were analyzed for thrombin-anti-thrombin complex (TAT), tissue factor (TF), tissue factor pathway inhibitor (TFPI), and D-Dimer.

RESULTS

Compression significantly attenuated the post-exercise increase in D-Dimer compared to the control group [median (range) SOCK: + 9.02 (- 0.34 to 60.7) ng/mL, CONTROL: + 25.48 (0.95-73.24) ng/mL]. TF increased following the marathon run [median (range), SOCK: + 1.19 (- 7.47 to 9.11) pg/mL, CONTROL: + 3.47 (- 5.01 to 38.56) pg/mL] in all runners. No significant post-exercise changes were observed for TAT and TFPI.

CONCLUSIONS

While activation of coagulation and fibrinolysis was apparent in all runners POST-marathon, wearing compression socks was shown to reduce fibrinolytic activity, as demonstrated by lower D-Dimer concentrations. Compression may reduce exercise-associated haemostatic activation when completing prolonged exercise.

Compression Socks Worn During Flight and Hemostatic Balance in Boston Marathon Runners on Oral Contraceptives

OBJECTIVE

To investigate the effect of oral contraceptive (OC) use and compression socks on hemostatic activation in women flying cross-country to and from a marathon.

DESIGN

Prospective study.

SETTING

2015 Boston Marathon.

PARTICIPANTS

Women were divided into non-OC using (CONTROL; n = 12), OC-using (OC; n = 15), and OC-using plus compression sock (OC + SOCK; n = 14) groups.

INTERVENTION

Women in OC + SOCK wore compression socks during flights to and from the marathon.

MAIN OUTCOME MEASURES

Venous blood samples were collected within 24 hours of arriving in Boston (EXPO), immediately after the marathon (RUN), and within 24 hours after a return flight home (Post-Flight) for analysis of thrombin-antithrombin complex (TAT), d-dimer, and tissue plasminogen activator (t-PA).

RESULTS

TAT did not increase with exercise (P = 0.48) and was not affected by group (P = 0.08) or the interaction between these 2 factors (P = 0.80). Group, time, and their interaction were significant for d-dimer (all P < 0.05) such that d-dimer increased with acute exercise to a greater extent (Δ d-dimer from expo to postrace = 909.5 ± 1021.9 ng/mL) in the OC + SOCK group relative to OC (Δ d-dimer = 240.0 ± 178.5 ng/mL; P = 0.02) and CONTROL (Δ d-dimer = 230.3 ± 120.3 ng/mL; P = 0.02). There was a significant effect of time, group, and the interaction on t-PA (all P < 0.01) such that t-PA increased with acute exercise to a greater extent (Δ t-PA from expo to postrace = 19.6 ± 10.0 ng/mL) in the CONTROL group relative to OC (Δ t-PA = 4.0 ± 1.8 ng/mL; P < 0.01) and OC + SOCK (Δ t-PA = 3.3 ± 1.2 ng/mL; P < 0.01).

CONCLUSIONS

Female runners using OCs did not exhibit disproportionately increased coagulation. The use of compression socks in women on OCs, surprisingly, resulted in a greater increase in d-dimer after exercise.

Time of day and short-duration high-intensity exercise influences on coagulation and fibrinolysis

Exercise has been demonstrated to have considerable effects upon haemostasis, with activation dependent upon the duration and intensity of the exercise bout. In addition, markers of coagulation and fibrinolysis have been shown to possess circadian rhythms, peaking within the morning (0600-1200 h). Therefore, the time of day in which exercise is performed may influence the activation of the coagulation and fibrinolytic systems. This study aimed to examine coagulation and fibrinolytic responses to short-duration high-intensity exercise when completed at different times of the day. Fifteen male cyclists (VO_2max: 60.3 ± 8.1 ml kg^-1 min^-1) completed a 4-km cycling time trial (TT) on five separate occasions at 0830, 1130, 1430, 1730 and 2030. Venous blood samples were obtained pre- and immediately post-exercise, and analysed for tissue factor (TF), tissue factor pathway inhibitor (TFPI), thrombin-anti-thrombin complexes (TAT) and D-Dimer. Exercise significantly increased plasma concentrations of TF (p < .0005), TFPI (p < .0006), TAT complexes (p < .0012) and D-Dimer (p < .0003). There was a time-of-day effect in pre-exercise TF (p = .004) and TFPI (p = .031), with 0830 greater than 1730 (p  .001), while 1730 was less than 2030 h (p = .008), respectively. There was no significant effect of time of day for TAT (p = .364) and D-Dimer (p = .228). Power output, TT time and heart rate were not significantly different between TTs (p > .05); however, percentage VO_2max was greater at 1730 when compared to 2030 (p = .04). Due to a time-of-day effect present within TF, peaking at 0830, caution should be applied when prescribing short-duration high-intensity exercise bout within the morning in populations predisposed to hypercoagulability.

Performance of wells score to predict deep vein thrombosis and pulmonary embolism in endurance athletes

INTRODUCTION

There are an increasing number of reports describing deep vein thrombosis (DVT) and/or pulmonary embolism (PE) in otherwise healthy endurance athletes. The Wells score is the most commonly used clinical prediction rule to diagnose DVT/PE in clinical populations. However, the Wells score may have limited utility for recognition of DVT/PE in athletes, contributing to missed or delayed diagnosis.

OBJECTIVE

We performed an analysis of the ability of the Wells score to identify DVT/PE events in athletes through a review of published case reports.

METHODS

A systematic search of the literature yielded 11 case reports.

RESULTS

The Wells score had a 100% failure rate in identifying athletes with DVT (0/6) and PE (0/5), resulting in a delayed diagnosis for DVT of 20 ± 14 days. Retrospectively removing 'differential diagnosis' from the clinical prediction rule for DVT changed the Wells score median from 0 (range: -1 to 0) to 2 (range: 1 to 2); the threshold for predicting DVT as 'likely'. There were limited clinical characteristics captured in the Wells score for PE that were applicable to athletes, highlighting the need for reappraisal. Although the Wells score failed to accurately triage athletes with known DVT and/or PE, the addition of a D-dimer value (mean: 1566 ± 758ng/dL) to the Wells score correctly identified 9/9 athletes.

CONCLUSIONS

The Wells score had a 100% failure rate for triaging athletes with known DVT/PE. When performed, D-dimer adequately facilitated the additional diagnostic testing required for a timely diagnosis of DVT/PE in athletes. Improving awareness of an atypical presentation of thrombotic events in athletes may reduce the widespread underestimation of DVT/PE among athletes and facilitate the additional testing required for a timely diagnosis.

The effect of exercise on coagulation and fibrinolysis factors in patients with peripheral arterial disease

Peripheral arterial disease is a widely prevalent atherosclerotic occlusive disorder. Symptoms commence with exercise-induced pain in the lower extremities, known as claudication. Despite the fact that exercise has been shown to improve fibrinolytic profile some patients, the effect of exercise on coagulation and fibrinolysis cascades in claudicants has not been comprehensively defined. Literature search in English language yielded 13 studies of exercise on claudicants, including 420 patients. Claudicants tend to have a higher coagulation activity at rest compared to healthy individuals, a trend that persists even after exercise. Post-exercise coagulation activity of claudicants is increased when compared to their respective baseline levels, but it is so in a non-consistent manner. From the available data, it has been suggested that claudicants have a functional and effective fibrinolytic mechanism in place, operating continuously at a relatively higher activity level compared to healthy individuals. Fibrinolysis seems to be activated by exercise; a positive outcome with a prolonged effect as shown by a few of the studies. A final conclusion whether coagulation or fibrinolysis activity is affected mostly by exercise type and intensity in claudicants could not be answered. All conclusions regarding the effect of exercise on the coagulation and fibrinolysis mechanisms should be taken under cautious consideration, due to the limited number of studies, the small number of patients and the different exercise strategies employed in each study. Further randomized studies with similar exercise protocols could provide safer conclusions in the future.

The effect of compression socks worn during a marathon on hemostatic balance

INTRODUCTION

Marathon running evokes parallel increases in markers of coagulation and fibrinolysis (i.e. hemostatic activation) immediately following strenuous, endurance exercise such that hemostatic balance is maintained. However, other factors incident to marathon running (i.e. dehydration, travel) may disproportionately activate the coagulatory system, increasing blood clot risk after an endurance event in otherwise healthy individuals. We investigated the effect of compression socks on exercise-induced hemostatic activation and balance in endurance athletes running the 2013 Hartford Marathon.

METHODS

Adults (n = 20) were divided into compression sock (SOCK; n = 10) and control (CONTROL; n = 10) groups. Age, anthropometrics, vital signs, training mileage and finishing time were collected. Venous blood samples were collected 1 day before, immediately after and 1 day following the marathon for analysis of coagulatory (i.e. thrombin-antithrombin complex [TAT] and D-dimer) and fibrinolytic (i.e. tissue plasminogen activator [t-PA]) factors.

RESULTS

Plasma D-dimer, TAT and t-PA did not differ between groups at baseline (p > 0.16). There were no significant group · time interactions (all p ≥ 0.17), however, average t-PA was lower in SOCK (8.9 ± 0.7 ng/mL) than CONTROL (11.2 ± 0.7 ng/mL) (p = 0.04). Average TAT also tended to be lower in SOCK (2.8 ± 0.2 µg/L) than CONTROL (3.4 ± 0.2 µg/L) (p = 0.07).

CONCLUSIONS

Our results suggest that overall hemostatic activation (both coagulation and fibrinolysis) following a marathon tended to be lower with compression socks. Thus, compression socks do not adversely influence markers of hemostasis, appear safe for overall use in runners and may reduce exercise-associated hemostatic activation in individuals at risk for deep vein thrombosis.

Biomarker Changes after Strenuous Exercise Can Mimic Pulmonary Embolism and Cardiac Injury—A Metaanalysis of 45 Studies

BACKGROUND

Biomarkers are well established for diagnosis of myocardial infarction [cardiac troponins, high-sensitivity cardiac troponins (hs-cTn)], exclusion of acute and chronic heart failure [B-type natriuretic peptide (BNP), N-terminal proBNP (NT-proBNP)] and venous thromboembolism (d-dimers). Several studies have demonstrated acute increases in cardiac biomarkers and altered cardiac function after strenuous sports that can pretend a cardiovascular emergency and interfere with state-of-the-art clinical assessment.

METHODS

We performed a systematic review and metaanalysis of biomarker and cardiovascular imaging changes after endurance exercise. We searched for observational studies published in the English language from 1997 to 2014 that assessed these biomarkers or cardiac function and morphology directly after endurance exercise. Of 1787 identified abstracts, 45 studies were included.

RESULTS

Across all studies cardiac troponin T (cTnT) exceeded the cutoff value (0.01 ng/mL) in 51% (95% CI, 37%–64%) of participants. The measured pooled changes from baseline for high-sensitivity cTnT (hs-cTnT) were +26 ng/L (95% CI, 5.2–46.0), for cTnI +40 ng/L (95% CI, 21.4; 58.0), for BNP +10 ng/L (95% CI, 4.3; 16.6), for NT-proBNP +67 ng/L (95% CI, 49.9; 84.7), and for d-dimer +262 ng/mL (95% CI, 165.9; 358.7). Right ventricular end diastolic diameter increased and right ventricular ejection fraction as well as the ratio of the early to late transmitral flow velocities decreased after exercise, while no significant changes were observed in left ventricular ejection fraction.

CONCLUSIONS

Current cardiovascular biomarkers (cTnT, hs-cTnT, BNP, NT-proBNP, and d-dimer) that are used in clinical diagnosis of pulmonary embolism, acute coronary syndrome, and heart failure are prone to alterations due to strenuous exercise. Hence, it is necessary to take previous physical exercise into account when a cardiac emergency is suspected.

Effect of cycling in the heat for 164 km on procoagulant and fibrinolytic parameters

PURPOSE

We assessed the impact of completing the Hotter'n Hell Hundred (HHH), an annual 164 km road cycling event performed in a hot environment, on hemostatic balance in men.

METHODS

Sixteen men who completed the ride in <6 h were included in this study. Plasma samples were collected on that morning of the ride (PRE) and immediately on the completion of the ride (IP). Primary hemostasis was assessed by platelet count and von Willebrand factor antigen (vWF:Ag). Coagulation was assessed by measuring prothrombin fragment 1 + 2 (PTF 1 + 2) and thrombin-antithrombin complex (TAT), whereas fibrinolysis was assessed by plasminogen activator inhibitor antigen (PAI-1 Ag), tissue plasminogen activator (tPA Ag), and D-Dimer analyses.

RESULTS

Compared to PRE, increases (p < 0.001) were observed at IP for platelets (39 %), vWF:Ag (65 %), PTF 1 + 2 (47 %), TAT (81 %), tPA Ag (231 %), PAI-1 Ag (148 %), and D-Dimer (54 %). PRE PAI-1 Ag concentrations were directly related to BMI and waist circumference (p < 0.05). D-Dimer concentrations at IP correlated positively with age (p < 0.05).

CONCLUSIONS

Completing the HHH activated the coagulation and fibrinolytic systems in balance. Age was positively correlated with IP D-Dimer concentrations. Additionally, participants displaying a larger BMI and waist circumference exhibited a positive correlation with PRE PAI-1 Ag concentrations.

The acute effect of moderate intensity aquatic exercise on coagulation factors in haemophiliacs

The objective of this cross-sectional study was to analyse the acute effect of aquatic exercise on haemostasis in persons with haemophilia. Ten adult haemophiliacs (8 type A, 2 type B) familiarized with aquatic training performed a 20-min exercise session in a swimming pool at an intensity of ~70% maximum heart rate (HR). Blood samples were collected immediately after the training session. The haemostatic parameters selected for analyses were factor VIII (FVIII), prothrombin time (PT), activated partial thromboplastin time (APTT) and fibrinogen. There were unclear effects of the exercise bout on FVIII and APTT, with a possibly beneficial effect on PT (-11·4%; 90% confidence interval: -26·1;3·3%), and a trivial change on fibrinogen levels. It was found an association between the mean rise in HR during exercise and the decrement in PT after exercise (r = 0·729; P = 0·026). The greater changes were observed in the patients diagnosed with a moderate level of haemophilia. It is concluded that a short bout of moderate intensity of aquatic exercise may have a positive influence on PT in adults with haemophilia with greater changes in those individuals exhibiting a greater rise in HR during exercise. This may be an important issue to the haemostatic control of haemophiliacs in clinical settings. Further studies are warranted for testing the influence of different aquatic exercise intensities on haemostasis.

Early exercise stress testing is safe after primary percutaneous coronary intervention

BACKGROUND

The optimal timing of exercise stress testing post primary percutaneous coronary intervention is uncertain with anecdotal evidence suggesting an increased risk of acute myocardial infarction and/or death if performed too early. This has translated into a delayed return to normal life activities following an acute myocardial infarction resulting in an increase in socio-economic burden.

AIMS

We hypothesize that early (within 7 days of primary percutaneous coronary intervention) exercise stress testing is safe.

METHODS

A prospective study of consecutive patients enrolled into the Cardiac Rehabilitation Program at a tertiary referral centre that underwent primary percutaneous coronary intervention, and who were able to perform a treadmill stress test were recruited. Timing of exercise stress testing was within 7 days post primary percutaneous coronary intervention and outcomes of death, acute myocardial infarction and other major adverse cardiac event were assessed 24 hours post exercise stress testing.

RESULTS

Recruited patients (n=230) aged between 29 and 78 (mean age 56 ± 10 years) with 191 being males (83%) and 39 being females (17%). While 28 patients had a positive stress test (12.2%), there were no deaths, acute myocardial infarction or any other major adverse cardiac event within 24 hours of performing the exercise stress testing. Mean METS achieved were 8.1 ± 2.3.

CONCLUSIONS

Early exercise stress testing after primary percutaneous coronary intervention appears safe.

Alterations in coagulatory and fibrinolytic systems following an ultra-marathon

PURPOSE

The aim of this study was to examine coagulatory and fibrinolytic responses to the Western States Endurance Run (WSER, June 23 to 24, 2012). The WSER is a 161-km (100 mile) trail foot race through the Sierra Nevada Mountains that involves 6,030 m of climb and 7,001 m of descent.

METHODS

We examined 12 men and 4 women [mean (95 % CI), age 44.6 years (38.7-50.6)] who completed the race (24.64 h; range 16.89-29.46). Blood samples were collected the morning before the race, immediately post-race, and 1 (D1) and 2 (D2) days post-race (corresponding to 51-54 h and 75-78 h from the start of the race, respectively). Hypercoagulable state was characterized by prothrombin fragment 1+2 (PTF 1+2) and thrombin-antithrombin complex (TAT). Fibrinolytic state was assessed by plasminogen activator inhibitor antigen (PAI-1 Ag), tissue plasminogen activator antigen (tPA Ag), and D-Dimer. Muscle damage was assessed by serum creatine kinase (CK) and myoglobin concentrations.

RESULTS

Significant (P ≤ 0.05) increases were observed immediately post-race for thrombin generation markers, PTF 1+2 (3.9-fold) and TAT (2.4-fold); markers of fibrinolysis, tPA Ag (4.0-fold), PAI-1 Ag (4.5-fold), and D-Dimer (2.2-fold); and muscle damage markers, CK (154-fold) and myoglobin (114-fold). Most markers continued to be elevated at D1, as seen by PTF 1+2, TAT (1.5- and 1.3-fold increase at D1), and D-Dimer (2.5- and 2.1-fold increase at D1 and D2, respectively). Additionally, PTF 1+2:tPA and TAT:tPA ratios, which assessed balance between coagulation and fibrinolysis, were slightly, but significantly increased at D1 (69 and 36 %) and D2 (19 and 31 %). CK and myoglobin also remained elevated at D1 (54- and 7-fold) and D2 (25- and 2-fold) time points.

CONCLUSION

The WSER produced extensive muscle damage and activated the coagulation and fibrinolytic systems. Since we observed a slight imbalance response between the two systems, a limited potential for thrombotic episodes is apparent in these highly trained athletes.

Effects of exercise on systemic inflammatory, coagulatory, and cardiac autonomic parameters in an inhalational exposure study

BACKGROUND

Intermittent moderate-intensity exercise is used in human inhalational exposure studies to increase the effective dose of air pollutants.

OBJECTIVE

To investigate the inflammatory, coagulatory, and autonomic effects of intermittent moderate-intensity exercise.

METHODS

We measured hemodynamic, electrocardiographic, inflammatory, and coagulatory parameters in peripheral blood of 25 healthy subjects across an exercise protocol that included running on a treadmill or pedaling a cycle ergometer for 30 minutes every hour over 4 hours in a climate-controlled chamber with a target ventilation of 20 L/min/m2 body surface area.

RESULTS

Intermittent moderate-intensity exercise induced a systemic proinflammatory response characterized by increases in leukocyte counts, C-reactive protein, monocyte chemoattractant protein-1, and interleukin-6, but did not change coagulation tendency or heart rate variability.

CONCLUSION

Interpretation of pollutant-induced inflammatory responses in inhalational exposure studies should account for signals and noises caused by exercise, especially when the effect size is small.

Ambient temperature affects thrombotic potential at rest and following exercise

INTRODUCTION

During exercise, ischemic risk increases, possibly due to changes in coagulation and fibrinolytic activity. Previous research suggests ambient temperature affects resting thrombotic potential, but the effect of heat and cold on hemostasis during exercise is unknown. The purpose of this study was to assess changes in coagulation and fibrinolysis during maximal exercise in hot and cold temperatures, and to compare those responses to exercise under temperate conditions.

MATERIALS & METHODS

Fifteen healthy men completed maximal exercise tests in hot (30°C), temperate (20°C) and cold (5° - 8°C) temperatures. Blood samples were obtained before and immediately after exercise and analyzed for concentrations of thrombin-antithrombin III (TAT), active tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1). Results were analyzed by ANOVA.

RESULTS

A main effect of time was observed for TAT (temperate=1.71 ± 0.82 - 2.61 ± 0.43 ng/ml, hot=1.81 ± 0.73 - 2.62 ± 0.67 ng/ml, cold=2.33 ± 0.65 - 2.89 ± 0.81 ng/ml, PRE to POST, respectively) and tPA activity (temperate=0.72 ± 0.44 - 2.71 ± 0.55 IU/ml, hot=0.72 ± 0.38 - 2.64 ± 0.61 IU/ml, cold=0.86 ± 0.45 - 2.65 ± 0.77 IU/ml, PRE to POST, respectively). A trend was observed for the PAI-1 response to exercise (temperate=14.5 ± 23.7 - 12.3 ± 20.2I U/ml, hot=15.1 ± 26.5 - 10.0 ± 15.1 IU/ml, cold=10.5 ± 10.4 - 7.9 ± 9.7 IU/ml, PRE to POST, respectively, p=0.08). TAT concentrations were significantly higher in cold compared to temperate and hot conditions.

CONCLUSION

Coagulation potential is elevated during exposure to cold temperatures. These data suggest that risk of an ischemic event may be elevated in the cold.

Effect of air travel on exercise-induced coagulatory and fibrinolytic activation in marathon runners

OBJECTIVE

Air travel and exercise change hemostatic parameters. This study investigated the effect of air travel on exercise-induced coagulation and fibrinolysis in endurance athletes.

DESIGN

A prospective longitudinal study.

SETTING

The 114th Boston Marathon (April 19, 2010).

PARTICIPANTS

Forty-one adults were divided into travel (T: 23 participants, living >4-hour plane flight from Boston) and nontravel (C: 18 participants, living <2-hour car trip from Boston) groups.

INDEPENDENT VARIABLES

Age, anthropometrics, vital signs, training mileage, and finishing time were collected.

MAIN OUTCOME MEASURES

Subjects provided venous blood samples the day before (PRE), immediately after (FINISH), and the day following the marathon after returning home (POST). Blood was analyzed for thrombin-antithrombin complex (TAT), tissue plasminogen activator (t-PA), hematocrit (Hct), and the presence of Factor V Leiden R506Q mutation.

RESULTS

Thrombin-antithrombin complex increased more in T subjects in PRE to FINISH samples (5.0 ± 4.0 to 12.9 ± 15.6 μg/L) than in C subjects (4.0 ± 1.2 to 6.1 ± 1.2 μg/L; P = 0.02 for comparison). The t-PA increased in both the T (5.4 ± 2.3 to 25.1 ± 12.2 ng/mL) and C (5.6 ± 2.0 to 27.7 ± 11.3 ng/mL) groups in PRE to FINISH samples, and this response did not differ between groups (P = 0.23 for comparison). Both groups exhibited similar t-PA and TAT values at POST that were not different than PRE (all P > 0.35). Age was related to the FINISH TAT values in T (r = 0.19; P = 0.04) but not in C (r = 0.03; P = 0.53) subjects.

CONCLUSIONS

Results suggest that the combination of air travel and marathon running induces an acute hypercoaguable state; this hemostatic imbalance is exaggerated with increasing age.

The effect of the acute submaximal exercise on thrombin activatable fibrinolysis inhibitor levels in young sedentary males

Depending on type, duration, and intensity of the exercise, changes occur in hemostasis. In this study, we evaluated the changes in the parameters of coagulation and fibrinolytic systems that happened after the submaximal aerobic exercises by bicycle ergomater. Twelve healthy male participants whose ages were between 21 and 28 have been included. The venous samples have been drawn before the exercise as well as at the 0 th, 15th, and 60th minutes after the submaximal exercise. The values of prothrombin time (PT), active partial thromboplastin time (aPTT), D-dimer, fibrinogen, plasminogen activator inhibitor 1 (PAI-1) and thrombin-activatable fibrinolysis inhibitor (TAFI) have been measured. Plasminogen activator inhibitor 1 values have shown an insignificant increase after exercise (P = .328), whereas, it has decreased significantly during the resting period (P = .033) Postexercise 15th and 60th minutes TAFI values have decreased significantly comparing to basal and postexercise (0 th minute) values (P = .001). Fibrinolytic system activation is observed after acute submaximal aerobic exercise of sedentary healthy participants.

Whole blood coagulation and platelet activation in the athlete: a comparison of marathon, triathlon and long distance cycling

Introduction

Serious thrombembolic events occur in otherwise healthy marathon athletes during competition. We tested the hypothesis that during heavy endurance sports coagulation and platelets are activated depending on the type of endurance sport with respect to its running fraction.

Materials and Methods

68 healthy athletes participating in marathon (MAR, running 42 km, n = 24), triathlon (TRI, swimming 2.5 km + cycling 90 km + running 21 km, n = 22), and long distance cycling (CYC, 151 km, n = 22) were included in the study. Blood samples were taken before and immediately after completion of competition to perform rotational thrombelastometry. We assessed coagulation time (CT), maximum clot firmness (MCF) after intrinsically activation and fibrin polymerization (FIBTEM). Furthermore, platelet aggregation was tested after activation with ADP and thrombin activating peptide 6 (TRAP) by using multiple platelet function analyzer.

Results

Complete data sets were obtained in 58 athletes (MAR: n = 20, TRI: n = 19, CYC: n = 19). CT significantly decreased in all groups (MAR -9.9%, TRI -8.3%, CYC -7.4%) without differences between groups. In parallel, MCF (MAR +7.4%, TRI +6.1%, CYC +8.3%) and fibrin polymerization (MAR +14.7%, TRI +6.1%, CYC +8.3%) were significantly increased in all groups. However, platelets were only activated during MAR and TRI as indicated by increased AUC during TRAP-activation (MAR +15.8%) and increased AUC during ADP-activation in MAR (+50.3%) and TRI (+57.5%).

Discussion

While coagulation is activated during physical activity irrespective of type we observed significant platelet activation only during marathon and to a lesser extent during triathlon. We speculate that prolonged running may increase platelet activity, possibly, due to mechanical alteration. Thus, particularly prolonged running may increase the risk of thrombembolic incidents in running athletes.

Exercise causing thrombosis

Thrombophilia refers to the increased tendency to form blood clots (thrombosis), which is a major cause of morbidity and mortality. Thrombosis is associated with various chronic conditions such as cancer, diabetes, renal disorders, and cardiovascular disease. The incidence and associated complications of thrombosis are likely to increase significantly in the next few decades because of aging populations. Regular exercise has been proposed to decrease the risk of developing thrombosis, although there are inconsistent data from studies investigating its effects, with reports of both increased and decreased thrombotic risk across a variety of subject cohorts. Confounders such as age, gender, hormonal variations, physical activity, underlying disease and treatment, and body composition also contribute to the difficulty in assessing and defining the precise effects of exercise in preventing thrombotic events. However, there is evidence suggesting that physical activity is beneficial for reducing thrombotic risk in younger individuals and those with chronic conditions. This article aims to summarize the known risk factors for thrombosis and briefly review the benefits of exercise in the general population. Furthermore, this article highlights the additional factors in a cohort of individuals that would (at first) appear unlikely to be at risk of thrombosis--elite athletes.

Blood coagulation activation and fibrinolysis during a downhill marathon run

Prolonged physical exercise is associated with multiple changes in blood hemostasis. Eccentric muscle activation induces microtrauma of skeletal muscles, inducing an inflammatory response. Since there is a link between inflammation and coagulation we speculated that downhill running strongly activates the coagulation system. Thirteen volunteers participated in the Tyrolean Speed Marathon (42,195 m downhill race, 795 m vertical distance). Venous blood was collected 3 days (T1) and 3 h (T2) before the run, within 30 min after finishing (T3) and 1 day thereafter (T4). We measured the following key parameters: creatine kinase, myoglobin, thrombin-antithrombin complex, prothrombin fragment F1 + 2, D-dimer, plasmin-alpha(2)-antiplasmin complexes, tissue-type plasminogen activator antigen, plasminogen-activator-inhibitor-1 antigen and thrombelastography with ROTEM [intrinsic pathway (InTEM) clotting time, clot formation time, maximum clot firmness, alpha angle]. Thrombin generation was evaluated by the Thrombin Dynamic Test and the Technothrombin TGA test. Creatine kinase and myoglobin were elevated at T3 and further increased at T4. Thrombin-antithrombin complex, prothrombin fragment F1 + 2, D-dimer, plasmin-alpha(2)-antiplasmin complexes, tissue-type plasminogen activator antigen and plasminogen-activator-inhibitor-1 antigen were significantly increased at T3. ROTEM analysis exhibited a shortening of InTEM clotting time and clot formation time after the marathon, and an increase in InTEM maximum clot firmness and alpha angle. Changes in TGA were indicative for thrombin generation after the marathon. We demonstrated that a downhill marathon induces an activation of coagulation, as measured by specific parameters for coagulation, ROTEM and thrombin generation assays. These changes were paralleled by an activation of fibrinolysis indicating a preserved hemostatic balance.

Hemostatic response to acute physical exercise in healthy adolescents

The chronic and immediate post-exercise responses in the hemostatic and fibrinolytic systems have been shown to be variable and reflect differing adaptations with ageing and responses to exercise protocols. This study investigated the effects of acute and exhaustive exercise on the amplitude and duration of hemostatic and fibrinolytic responses in young adolescent males. The sample comprised 10 sedentary boys (13.2+/-0.5 years, 55.8+/-11.3kg, 165.7+/-7.4cm), who had not exercised or received any medication for at least 2 weeks before the experiments. The subjects performed exhaustive stepping exercise, consisting of 1s up and down cycles to fatigue. When the subjects were unable to maintain the required stepping rhythm, they were given a 30s recovery period. Following each 30s recovery participants recommenced the stepping cadence until fatigue prevented them continuing. Venous blood samples were drawn before and immediately, 1 and 24h after exercise to assess the following coagulation and fibrinolytic parameters: Platelet counts, activated partial thromboplastin time (aPTT), prothrombin time (PT), coagulation factor VIII (FVIII:C), von Willebrand factor (vWF), fibrinogen concentration, thrombin-antithrombin complex (TAT), D-dimer, plasminogen activator inhibitor (PAI-1), and tissue-type plasminogen activator (t-PA). Immediately following exercise, platelet counts, aPTT, FVIII, vWF and t-PA were significantly elevated in contrast to PAI-1, which decreased significantly until 1h after exercise. FVIII and platelet counts were elevated at 1 and 24h after exercise, respectively. Only the parameters FVIII and PAI-1 did not return to baseline values during the first hour after physical exercise. When compared to adults the results revealed different rates and ranges of coagulation and fibrinolysis parameters being activated by exhaustive exercise in this group of adolescents.

Effects of Mild Leg Exercise in a Seated Position on Haemostatic Parameters Under Normobaric Hypoxic Conditions

This study tested the hypothesis that in humans mild leg exercise affects haemostasis in normobaric hypoxia and thus avoids the development of a deep venous thrombosis (DVT). Eight young men breathed in a 15.4% oxygen in nitrogen gas mixture for 2 hrs while seated at rest (R) or seated and performing a 3-min mild leg exercise program (Ex) at 15-min intervals to assess the impact of mild leg exercise on haemostatic parameters related to the risk of developing DVT, as has been discussed for hypobaric hypoxic conditions during commercial airline travel. Capillary blood gases were analysed every 30 min. Heart rate was monitored continuously. Haemostatic parameters were analysed from venous blood at the beginning, after 1 and 2 hrs, and after a 30-min resting period in normoxic conditions. Plasminogen-activator-inhibitor-1 diminished in both tests in hypoxia, but not after the resting period. Antithrombin-III decreased in R in the hypoxic period. Platelet count, international normalized ratio, partial thromboplastin time remained unchanged, as did highly sensitive parameters like tissue-plasminogen-activator, α2-antiplasmin, d-dimers, thrombin-antithrombin-III-complexes, and prothrombin-fragments 1 and 2. The haematocrit decreased significantly in R. The mild leg execise prevented the decrease of antithrombin-III and caused an increase in haematocrit after an initial drop in the first hour. The present study revealed that normobaric hypoxia did not have clinically relevant effects on haemostasis in humans. Mild leg exercise carried out under those conditions did not lead, via alterations in haemostasis, to a reduced risk of DVT. Key words: local aerobic exercise, haemostasis, hypoxia, thrombosis

Hematologic Disorders in the Athlete

Optimal athletic performance depends on proper function of many organs, including the blood. This is underscored by the focus of endurance athletes on increased hemoglobin through training at altitude or exogenous erythropoietin. Several other aspects of the hematologic system can also affect or be influenced by physical activity. In this article, the authors briefly discuss inherited abnormalities of the blood that can manifest themselves in athletes. We then discuss the effects of exercise on the blood, and acquired abnormalities of blood cells or coagulation parameters that occur in athletes, and that can influence performance or cause other symptoms.

Effects of prolonged strenuous exercise (marathon running) on biochemical and haematological markers used in the investigation of patients in the emergency department

OBJECTIVES

To investigate the effects of strenuous exercise on commonly used biochemical and haematological variables in subjects running the 2002 London marathon.

METHODS

34 healthy volunteers (7 female, 27 male) were recruited for the study. Blood was taken before the start (at registration) and immediately after completion of the marathon. Samples were analysed for urea and electrolytes, liver function tests, creatine kinase (CK), CK-MB isoenzyme, myoglobin, troponin I, full blood count, a clotting screen, and D-dimers. The results before and after exercise were compared. Pearson's correlation coefficients were calculated for all variables.

RESULTS

Significant increases were found in CK, CK-MB, aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and myoglobin following the marathon. However, there was no significant change in the level of troponin I. There was also evidence of activation of the coagulation and fibrinolytic cascades following the marathon, with a reduction in activated partial thromboplastin time, a reduction in fibrinogen, and an increase in D-dimers.

CONCLUSIONS

The results confirm previous individual studies on marathon running and the biochemical and haematological tests routinely carried out in hospital. These are affected by prolonged exercise, and "abnormal" results in these tests may be normal after prolonged exercise and therefore not diagnostic of a disease process. The results of investigations in patients who have been exercising should be interpreted with caution.

Obesity and impaired fibrinolysis: role of adipose production of plasminogen activator inhibitor-1

Obesity is the central promoter of the metabolic syndrome which also includes disturbed fibrinolysis in addition to hypertension, dyslipidaemia and impaired glucose tolerance/type 2 diabetes mellitus. Plasminogen activator inhibitor-1 (PAI-1) is the most important endogenous inhibitor of tissue plasminogen activator and uro-plasminogen activator, and is a main determinant of fibrinolytic activity. There is now compelling evidence that obesity and, in particular, an abdominal type of body fat distribution are associated with elevated PAI-1 antigen and activity levels. Recent studies established that PAI-1 is expressed in adipose tissue. The greater the fat cell size and the adipose tissue mass, the greater is the contribution of adipose production to circulating PAI-1. Experimental data show that visceral adipose tissue has a higher capacity to produce PAI-1 than subcutaneous adipose tissue. Studies in human adipocytes indicate that PAI-1 synthesis is upregulated by insulin, glucocorticoids, angiotensin II, some fatty acids and, most potently, by cytokines such as tumour necrosis factor-alpha and transforming growth factor-beta, whereas catecholamines reduce PAI-1 production. Interestingly, pharmacological agents such as thiazolidinediones, metformin and AT(1)-receptor antagonists were found to reduce adipose expression of PAI-1. In addition, weight loss by dietary restriction or comprehensive lifestyle modification is effective in lowering PAI-1 plasma levels. In conclusion, impaired fibrinolysis in obesity is probably also due to an increased expression of PAI-1 in adipose tissue. An altered function of the endocrine system and an impaired auto-/paracrine function at the fat cell levels may mediate this disturbance of the fibrinolytic system and thereby increase the risk for cardiovascular disease..

Comparison of t-PA and u-PA levels in maximal treadmill and deep-water running

BACKGROUND

The differences of urokinase-type plasminogen activator (u-PA) and tissue-type plasminogen activator (t-PA) between maximal treadmill and deep-water running have not been reported. The purpose of this investigation was to compare u-PA and t-PA levels during maximal treadmill and deep-water running.

METHODS

Six male subjects carried out two maximal exercises, one on a treadmill and the other running in deep water using a vest. The u-PA, t-PA, total plasminogen activator inhibitor (PAI-1), epinephrine, and norepinephrine in plasma and lactate and ammonia in blood concentrations were measured after maximal exercise.

RESULTS

The blood lactate and ammonia concentrations were significantly higher in treadmill running than in deep-water running during recovery following exercise (P < 0.05). At 1 min after exercise, the plasma epinephrine, norepinephrine levels, and the u-PA and t-PA levels were higher in treadmill running compared with that in deep-water running (P < 0.05). No significant difference between the two runs was found in PAI-1 level.

CONCLUSION

The maximal treadmill running induced a greater increase in u-PA and t-PA levels than maximal deep-water running.

Effects of strenuous exercise on haemostasis

OBJECTIVES

To review the effects of exercise on haemostasis and examine the possible clinical sequelae of these changes.

METHODS

The search strategy included articles from 1966 to August 2002 using Medline and SportDiscus databases, and cross referencing the bibliographies of relevant papers.

RESULTS

Exercise results in activation of both the coagulation and fibrinolytic cascades, as shown by a reduction in whole blood clotting time and activated partial thromboplastin time, an increase in the activity of several components of the cascades, and an increase in fibrin degradation products. In vitro tests suggest that coagulation remains activated after fibrinolysis has returned to baseline levels.

CONCLUSIONS

Both the coagulation and fibrinolytic cascades are stimulated by strenuous exercise, but the temporal relation between the two and its clinical significance remains to be clarified. Doctors and athletes should be aware of the haemostatic changes induced by exercise, and further work is needed to clarify the possible role of these changes in sudden cardiac death.

Exercise-induced changes in coagulation and fibrinolysis in healthy populations and patients with cardiovascular disease

This review highlights the clinical significance of coagulation and fibrinolytic responses, and adaptations in healthy individuals and patients with cardiovascular disease (CVD). Much of the review focuses on indicators of the potential for coagulation and fibrinolysis. The terms 'coagulation potential' and 'fibrinolytic potential' are used frequently, as much of the literature in the area of exercise haemostasis evaluates factors that reflect an increased potential for coagulation, while coagulation per se, may or may not be occurring. Similarly, fibrinolysis is definitively the lysis of inappropriate or excessive blood clot, which may or may not be occurring when the enzymes that stimulate fibrinolysis are activated. Nevertheless, markers of coagulation and fibrinolytic potential are associated with CVD, ischaemic events, and cardiovascular mortality. Additionally, fibrinolytic potential is associated with other established CVD risk factors. Ischaemic events triggered by physical exertion are more likely to occur due to an occlusive thrombus, suggesting the exercise-induced responses related to haemostasis are of clinical significance. The magnitude of increase in coagulation potential, platelet aggregation and fibrinolysis appears to be primarily determined by exercise intensity. Patients with CVD may also have a larger increase in coagulation potential during acute exercise than healthy individuals. Additionally, the magnitude of the fibrinolytic response is largely related to the resting fibrinolytic profile of the individual. In particular, high resting plasminogen activator inhibitor-1 may diminish the magnitude of tissue plasminogen activator response during acute exercise. Therefore, acute responses to exercise may increase the risk of ischaemic event. However, chronic aerobic exercise training may decrease coagulation potential and increase fibrinolytic potential in both healthy individuals and CVD patients. Due to the aforementioned importance of resting fibrinolysis on the fibrinolytic response to exercise, chronic aerobic exercise training may cause favourable adaptations that could contribute to decreased risk for ischaemic event, both at rest and during physical exertion.

Exercise and Training Effects on Blood Haemostasis in Health and Disease

In recent years, the dysfunction of the haemostatic system in relation to the clinical complications from arterioscleroses and cardiovascular diseases has become more recognised. Blood coagulation and fibrinolysis comprise two important physiological systems, which are regulated by a balance between activators and inhibitors. Activation of blood coagulation is associated with accelerated clot formation, whereas activation of blood fibrinolysis enhances the breakdown of the blood clot. Available evidence suggests that strenuous exercise induces activation of blood coagulation with simultaneous enhancement of blood fibrinolysis. Although the responses of blood coagulation and fibrinolysis appear to be related to the exercise intensity and its duration, recent reports suggest that moderate exercise intensity is followed by activation of blood fibrinolysis without concomitant hyper-coagulability, while very intense exercise is associated with concurrent activation of blood coagulation and fibrinolysis. Similar to blood coagulation and fibrinolysis, systemic platelet-related thrombogenic factors have been shown to be involved in the initiation and progression of atherogenesis and plaque growth. Although exercise effects on platelet aggregation and function in healthy individuals have been examined, the results reported have been conflicting. However, for patients with coronary heart disease, the balance of evidence available would strongly suggest that platelet aggregation and functions are increased with exercise. Few studies are available concerning the influence of training on blood coagulation and fibrinolysis and the exact effects of exercise training on the equilibrium between blood coagulation and fibrinolysis is not as yet known. Although the effects of physical training on platelets have been briefly investigated, available meagre evidence suggests that exercise training is associated with favourable effects on platelet aggregation and activation in both men and women.

Hemostatic Alterations in Patients With Obstructive Sleep Apnea and the Implications for Cardiovascular Disease *

STUDY OBJECTIVES

Patients with obstructive sleep apnea (OSA) are at increased risk for coronary artery and cerebrovascular diseases. Numerous studies suggest that a hypercoagulable state is prospectively related to atherothrombotic events. This review explores whether changes in hemostasis may constitute one biological link between OSA and vascular disease.

DESIGN

Ten studies on hemostatic variables in OSA were located by electronic library search and descriptively reviewed. Work on hemostatic function with physiologic conditions similar to those found in OSA (hypoxemia and hyperactivity of the sympathetic nervous system) was considered to discuss potential molecular mechanisms of procoagulant disturbances in OSA.

MEASUREMENTS AND RESULTS

The reviewed data suggest that, as compared to non-OSA control subjects, patients with OSA have elevated plasma fibrinogen levels, exaggerated platelet activity, and reduced fibrinolytic capacity. Although not consistently shown, severity of OSA (ie, apnea-hypopnea index) and plasma epinephrine were independent predictors of platelet activity, and average minimal oxygen saturation was an independent predictor of fibrinogen. In some studies, treatment with continuous positive airway pressure decreased platelet activity, plasma fibrinogen levels, and activity of clotting factor VII.

CONCLUSIONS

There is some evidence for a hypercoagulable state in OSA, which might help explain the increased prevalence of vascular diseases in this population. To further confirm such a notion, future studies need to be performed on sufficiently large samples to be able to control for confounders of hemostatic activity. Prospective studies are needed to examine the association between hemostasis molecules and strong vascular end points.

Effects of acute exercise on hemorheological, endothelial, and platelet markers in patients with chronic heart failure in sinus rhythm

BACKGROUND

Chronic heart failure (CHF) is associated with an increased risk of thrombosis and thromboembolic events, including stroke and venous thromboembolism. which may be related to a prothrombotic or hypercoagulable state. Acute vigorous exercise has been associated with activation of hemostasis, and this risk may well be particularly increased in patients with CHF.

HYPOTHESIS

The study was undertaken to determine whether acute exercise would adversely affect abnormalities of hemorheological (fibrinogen, plasma viscosity, hematocrit), endothelial (von Willebrand factor), and platelet markers (soluble P selectin) in patients with CHF.

METHODS

We studied 22 ambulant outpatients (17 men; mean age 65+/-9 years) with stable CHF (New York Heart Association class II-III and a left ventricular ejection fraction of < or =40%) who were exercised to exhaustion on a treadmill. Results were compared with 20 hospital controls (patients with vascular disease, but free of CHF) and 20 healthy controls.

RESULTS

Baseline von Willebrand factor (p = 0.01) and soluble P-selectin (p = 0.006) levels were significantly elevated in patients with CHF when compared with controls. In the patients with CHF who were exercised, plasma viscosity, fibrinogen, and hematocrit levels increased significantly, both immediately post exercise and at 20 min into the recovery period (repeated measures analysis of variance, all p<0.05). There was a positive correlation between exercise workload and the maximal changes in plasma viscosity in the patients with CHF (Spearman r = 0.5, p = 0.02). Plasma viscosity levels increased with exercise in the hospital control group, although no other exercise-induced changes were noted in this group.

CONCLUSION

The present study indicates that the hemorheological indices. fibrinogen, and hematocrit specifically increase during acute exercise in patients with CHF. Although moderate exercise should be encouraged in patients with CHF, vigorous exercise should probably be avoided in view of its potential prothrombotic effects in this high-risk group of patients.

Exercise and thrombosis

Long-term moderate or strenuous physical activity is associated with a considerable reduction in cardiovascular morbidity and mortality in primary and secondary prevention. Various mechanisms, including changes in lipids, lifestyle habits, and other positive physiologic effects, have been suggested to mediate these beneficial effects. In addition, the hemostatic and fibrinolytic systems appear to play an important role. Fibrinogen has been convincingly shown to be an independent cardiovascular risk factor. Other hemostatic and fibrinolytic parameters that are predictive of coronary events include factor VII, platelet hyperreactivity, plasminogen-activator inhibitor 1 (PAI-1), and tissue-plasminogen activator. The effects of exercise on fibrinogen have been intensively studied. Several randomized controlled trials, various other intervention studies and a large number of population-based cross-sectional studies all found an inverse relationship between measures of sport activity or leisure activity and plasma fibrinogen. The magnitude of the effect reported might be associated with a sizeable reduction in major coronary events. Relatively few data are available on the effects of endurance exercise on markers of the fibrinolytic system, with inconsistent results. Acute exercise leads to a transient activation of the coagulation system, which is accompanied by an increase in the fibrinolytic capacity in healthy subjects. Patients with ischemic heart disease, who cannot increase their fibrinolytic potential, however, may be at considerable risk for acute ischemic events if they are exposed to unaccustomed strenuous physical exertion.

Post-exercise alcohol ingestion perturbs blood haemostasis during recovery

It is known that exercise induces modification in blood haemostasis. It is, however, not known whether alcohol consumption post-exercise influences these modifications during recovery. Eleven moderately active young men were studied immediately after a standardised cycle ergometer test and during the 24-hour period of recovery. Alcohol (0. 7 g/kg body mass) was given 1 hour after exercise on one test occasion, while an equal volume of alcohol-free solution was administered on the other. Exercise induced a significant increase in factor VIII activity with a significant shortening of activated partial thromboplastin time. Parallel increases in tissue plasminogen activity and antigen with a concomitant decrease in tissue plasminogen activator inhibitor-1 activity were also observed after exercise. During recovery, while the increase in factor VIII activity post-exercise persisted in both trials, fibrinolytic activity demonstrated a sharp fall. The elevated factor VIII activity was significantly higher at 5 and 22 hours during the alcohol trial compared with the control. Although no demonstrable effect of alcohol on tissue plasminogen activator activity was present from 1 hour after ingestion onward, tissue plasminogen activator antigen and tissue plasminogen activator inhibitor-1 antigen increased significantly 22 hours following alcohol ingestion. Further comparison between trials revealed a higher plasminogen activator inhibitor-1 activity 5 hours after alcohol ingestion. In conclusion, exercise-induced changes to blood haemostasis are balanced during exercise but not during recovery. Alcohol consumption after physical exercise further perturbs blood haemostasis and could constitute a thrombotic risk.

Exercise induces a change in plasma fibrinogen concentration: fact or fiction?

This study examined the effect of exercise on plasma fibrinogen concentrations with simultaneous measurements of plasma volume changes. Eight moderately active males aged 26.6+/-3.6 years (mean +/- SD) completed maximal (VO2max) and submaximal (75% VO2max for 30 minutes) exercise trials separated by 7 days. Venous blood samples were obtained at rest, immediately postexercise, and following 30 minutes of recovery. Whole blood was analysed for haematocrit and haemoglobin, while citrated plasma was assayed for fibrinogen levels. Values of haematocrit and haemoglobin before and after exercise were utilised for the estimation of plasma volume changes. Plasma volume decreased (p<0.05) immediately following both maximal (-17.7+/-5.1%) and submaximal (-14.3+/-4.1%) exercise. Exercise resulted in decreased plasma fibrinogen levels (maximal exercise: from 266.3+/-14.5 to 222.2+/-23.9 mg x dL(-1); submaximal exercise: from 239.5+/-45.4 to 209.7+/-42.4 mg x dL(-1)) only when postexercise raw data were corrected for the contraction of plasma volume. It is concluded therefore that changes in plasma volume in response to exercise should be taken into account when interpreting exercise effects on plasma fibrinogen concentration.