title: The effect of submaximal exercise on platelet aggregation during late follicular and midluteal phases in women.
abstract: BACKGROUND
  The key role of platelets in the pathogenesis of atherosclerosis prompted considerable interest on the effect of physical exercise on platelets. Due to probable menstrual cycle variations, only a limited number of investigations have studied the effect of exercise on platelets in women. The study was undertaken to determine the effect of acute submaximal exercise on platelet aggregation and thromboxane A(2) (TxA(2)) formation in females during their late follicular and midluteal phases.
  
  
  METHODS
  Twelve healthy, sedentary, female volunteers performed 15 min of cycling exercise at a workload that increased their heart rate to 75% of maximal in two phases of the menstrual cycle. The maximal rate of ADP and collagen-induced platelet aggregation was evaluated on citrated whole blood using the impedance technique. Thrombin-induced thromboxane A(2) formation was evaluated by the measurement of thromboxane B(2) (TxB(2)) level by enzyme-linked immunoassay.
  
  
  CONCLUSIONS
  No significant difference was found between maximal rates of platelet aggregation measured in the different phases of menstrual cycle. Collagen-induced platelet aggregation and platelet count increased significantly after the exercise in both late follicular and midluteal phases (p<0.05). ADP-induced platelet aggregation did not change due to the exercise during the two phases of menstrual cycle. The thromboxane B(2) level measured in the midluteal phase was significantly higher than that measured in late follicular phase at rest. It was significantly increased after the exercise in late follicular phase while no significant difference was found between pre-exercise and postexercise levels in the midluteal phase. The differences in thromboxane A(2) formation were pointed out in the changes in platelet reactivity status. The inhibitory systems for platelets need further investigations. Our findings support the idea that menstrual variations do not have pronounced and acute effects on both platelet aggregation and response of platelets to acute exercise.
authors.affiliation: Department of Physiology, Ankara University Faculty of Medicine, Sihhiye Ankara 06100, Turkey. gersoz@medicine.ankara.edu.tr
authors.forename: G
authors.initials: G
authors.lastname: Ersöz
authors.forename: A M
authors.initials: AM
authors.lastname: Zergeroğlu
authors.forename: A
authors.initials: A
authors.lastname: Yakaryilmaz
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000328:Adult; D001161:Arteriosclerosis / Q000097:blood / Q000209:etiology; D003094:Collagen / Q000494:pharmacology; D004958:Estradiol / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005260:Female; D005498:Follicular Phase / Q000097:blood*; D006801:Humans; D066298:In Vitro Techniques; D008183:Luteal Phase / Q000097:blood*; D010974:Platelet Aggregation / Q000187:drug effects / Q000502:physiology*; D011374:Progesterone / Q000502:physiology; D013928:Thromboxane A2 / Q000096:biosynthesis; D013929:Thromboxane B2 / Q000097:blood
chemical_list: D011374:Progesterone; D004958:Estradiol; D013929:Thromboxane B2; D013928:Thromboxane A2; D000244:Adenosine Diphosphate; D003094:Collagen