Exercise stimulates the release of hematopoietic and endothelial progenitor cells (EPC) from the bone marrow. However, no data are available concerning the time frame of EPC release during strenuous exercise. The aim of the present study was to investigate the time-dependent release of progenitor cells during strenuous exercise. Eighteen healthy young men cycled for 4 h continuously at 70% of their individual anaerobic threshold. Peripheral blood was drawn at 16 predefined time points during and after finishing cycling. A significant rise in heart rate and leukocytes was obvious, whereas lactate levels and hematocrit did not change. The amount of circulating progenitor cells, EPCs, mature endothelial cells (mECs), and microparticles, quantified by flow cytometry, showed a significant time-dependent increase at 210/240 min. In addition a very early rise in VEGF and later increase in IL-6, both measured by ELISA, were evident. All observed changes were normalized 24 h after finishing the test. In conclusion, strenuous activity in healthy individuals leads to a time-dependent increase in mECs, PCs, and EPCs that may be related to VEGF and IL-6.

The influence of different exercise intensities on haemostasis in healthy, untrained subjects has not been intensively studied. We investigated untrained subjects for alterations in coagulation and fibrinolysis induced by two exercise intensities, precisely controlled by individual anaerobic threshold (IAT). Twenty-five healthy, untrained non-smokers (age 25 ± 3 years; relative VO(2) peak 43.1 ± 5.2 ml/kg/min) underwent exercise tests at 80% (moderate) and 100% (strenuous) of IAT for 60 min. Blood samples were taken after 30 min rest and immediately after exercise. The present results reveal that an exercise intensity at 100% IAT induces a more pronounced coagulation activity than exercises at 80% IAT. 100% IAT led to a significant higher increase in FVIII (80% IAT 85 ± 33 to 114 ± 30% vs. 100% IAT 81 ± 20 to 132 ± 29%) and TAT (80% IAT 2.5 ± 1.4 to 2.9 ± 1.0 μg/l vs. 100% IAT 2.6 ± 1.0 to 5.4 ± 4.2 μg/l). Furthermore, both exercises affected fibrinolysis, but it was significantly higher at 100% IAT (tPA activity; 80% IAT 0.44 ± 0.17 to 4.65 ± 2.67 U/ml vs. 100% IAT 0.43 ± 0.19 to 6.47 ± 3.97 U/ml). The data show that fibrinolytic activity is significantly elevated already after moderate exercise (80% IAT). After strenuous exercise (100% IAT), coagulation is more sharply enhanced together with a higher increase of fibrinolysis in comparison with 80% IAT. However, haemostasis seems to be in balance after moderate as well as after strenuous exercise intensity in healthy, untrained participants. Based on these data, exercise-induced changes of both haemostatic systems should also be tested in patients with cardiovascular diseases in order to be in a position to give recommendations for endurance training modalities in rehabilitation training.

Randomized controlled trials (RCTs) on the topic of physical training and blood coagulation are rare and the effects are unclear. The aim of this study was to investigate whether endurance training adjusts blood coagulation and fibrinolysis at rest and after exercise. The study included 50 healthy untrained non-smokers randomized into training (TR 49 ± 6 years) or control group (CO 48 ± 6 years). Each subject performed an exercise test adjusted at 80 % individual anaerobic threshold (IAT) for 60 min before and after 12 weeks (80 % IAT: before TR 123 ± 20, CO 125 ± 26 W; after TR 148 ± 23 W, CO 127 ± 25 W; mean ± SD). Blood was taken at rest and after exercise to determine coagulation (e.g., aPTT, thrombin potential, TAT, F1+2, several coagulation factors) and fibrinolytic (e.g., tPA, PAI) parameters. The training intervention induced an elevation of physical capacity in TR by 17 % (rel. VO2max) that led to a statistical relevant prolongation of aPTT at rest. Although absolute power output during the second exercise test was 20 % higher in TR, we detected an attenuated exercise-induced decrease of aPTT and attenuated increase of F1+2 after training. Resting levels of tPA- and PAI-Ag decreased slightly but not significantly after training. Exercise-induced changes were comparable after training in spite of higher power output in TR. Although the effects are small in healthy men, training modifies exercise-induced blood coagulation positively. The fact that exercise-induced changes in blood coagulation and fibrinolysis are rather attenuated or unchanged in the training group, in spite of a 20 % higher absolute power output during exercise, substantiates the adjusting effect of endurance training and the importance of physical fitness in primary prevention.

No abstract

Increased age is associated with a higher risk of thrombotic events. The aim of this study was to investigate the age-related changes in hemostasis before and after moderate exercise controlled by individual anaerobic threshold as recommended for rehabilitation training. In this study, 24 young (25 + 1 years) and 24 middle-aged healthy nonsmokers (48 + 1 years) underwent an individualized exercise test with 80% of individual anaerobic threshold (young individuals: 127 + 6 W; middle-aged individuals: 128 + 5 W; values are expressed as mean + standard error of mean) for 60 minutes. The blood samples were collected before and after the exercise. The age-related higher (P .05) levels could be detected in factors II, VII, VIII, IX, XI, XII, prothrombin fragment 1þ2, in tissue plasminogen activator antigen and activity, as well as in plasminogen. The relative exercise-induced increases in these parameters were similar in both groups, although beginning at a higher level for those in the middle-aged group. A statistically enhanced increase after exercise in the middle-aged group could be shown in prothrombin fragment 1þ2 (young individuals: 98 + 6 to 102 + 6 pmol/L; middle-aged individuals: 138 + 7 to 156 + 8 pmol/L) and in thrombin-antithrombin complex (young individuals: 2.2 + 0.1 to 3.1 + 0.2 mg/L; middle-aged individuals: 2.4 + 0.3 to 3.9 + 0.6 mg/L); the latter only showing a tendency. The data show the age-related changes with a rise in blood coagulation and fibrinolysis in a healthy middle-aged group compared with younger participants. Moderate exercise leads to comparably relative increases in hemostatic parameters but starting at higher levels. However, the exercise-induced thrombin generation (prothrombin fragment 1þ2) is enhanced in the middle-aged participants in comparison with younger participants, but may be compensated by a sufficient fibrinolysis, and therefore the hemostatic system remains in balance.