Journal of Applied Physiology, Vol 53, Issue 2 330-334, Copyright © 1982 by American Physiological Society
Oral contraceptives and fibrinolysis among female cyclists before and after exercise
I. A. Huisveld, A. J. Hospers, M. J. Bernink, M. W. Biersteker, W. B. Erich and B. N. Bouma
The effect of oral contraceptives on a number of plasma fibrinolytic
variables and antithrombin III was studied in 20 highly trained women
before and immediately after exhaustive exercise on a bicycle ergometer.
Two groups were studied, 11 women using an oral contraceptive agent (OCA
group) and 9 women not using an oral contraceptive (control group). Factor
XII, prekallikrein, plasminogen, alpha 2-antiplasmin, and antithrombin III
activities were determined in plasma as well as a number of cardiovascular,
respiratory, and metabolic components. Resting values showed a
significantly higher level of prekallikrein and plasminogen in the OCA
group compared with the control group. Exercise plasma values of components
of the fibrinolytic system were significantly higher than resting values in
both groups. However, when corrected for plasma volume changes, the
exercise levels of prekallikrein and antithrombin III were significantly
decreased in the OCA group only, whereas alpha 2-antiplasmin exercise level
was significantly lower in both groups. Our results indicate that use of
OCA even with an estrogen dosage as low as 30 micrograms has an effect on
resting and exercise fibrinolytic variables; an effect, however, which does
not seem to interfere with maximal performance in trained women.
