The effect of oral contraceptives and exercise on hemostatic and fibrinolytic mechanisms in trained women

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.

Effects of combination oral contraceptives on strength development in women athletes

This study was designed to investigate the effects of combination oral contraceptive agents (OCAs) on strength and torque production in collegiate women softball and water polo athletes who participated in a 12-week strength development program. A double-blind research design was used to mask subjects to the main outcome of interest. Thirty-one women collegiate softball and water polo players were divided into experimental (OCA users, n = 13), and control (non-OCA users, n = 18) groups. All subjects participated in the same supervised 12-week preseason strength development program. One-repetition maximum bench press (1RMBP), 10-repetition maximum leg extension (10RMLE), isokinetic peak torque bench press (IKBP), and isokinetic peak torque leg extension (IKLE) data were collected at weeks 0 (pre-test), 4, 8, and 12 (post-test). Significant increases in strength and torque production over time were identified regardless of group for 1RMBP, 10RMLE, and IKLE. No significant differences in IKBP torque production occurred during the 12-week strength training program. No significant differences in 1RMBP, 10RMLE, IKBP, or IKLE occurred between the OCA users and the non-OCA users groups. It was concluded that, within the limitations of the study, the use of combination OCAs did not provide sufficient androgenic effect to increase strength gains beyond the stimulus of the training protocol.

The influence of oral contraceptives on athletic performance in female athletes

It is now estimated that the prevalence of oral contraceptive use in athletic women matches that of women in the general population. The oral contraceptive pill (OCP) reduces cycle-length variability and provides a consistent 28-day cycle by controlling concentrations of endogenous sex hormones. The OCP is administered in three different forms that differ widely in chemical constitution and concomitant effects on the human body. As fluctuation in sex steroids are believed to be a possible causal factor in performance and exercise capacity, it is imperative to understand the effect of administering the various types of OCP on women. However, the research into oral contraceptives and exercise performance is not consistent. The type of OCP administered (monophasic, biphasic or triphasic), as well as the type and dose of estrogen and progestogen within, will have varying effects on exercise. To date, research in the area of oral contraceptives and exercise capacity is sparse and much has been plagued by poor research design, methodology and small sample size. It is clear from the research to date that more randomised clinical trials are urgently required to assess the array of OCP formulations currently available to women and their concomitant effect on health and exercise capacity. Therefore, the purpose of this article is to critically appraise the literature to date and to provide a current review of the physiological scientific knowledge base in relation to the OCP and exercise performance. In addition, methodological control, design and conduct will be considered with future areas of research highlighted.

Decreased maximal aerobic capacity with use of a triphasic oral contraceptive in highly active women: a randomised controlled trial

BACKGROUND

Oral contraceptives are commonly used by women athletes. However, their effect on athletic performance is unclear.

OBJECTIVES

To examine the effects of a moderate dose, triphasic oral contraceptive on measures of athletic performance in highly trained women athletes.

METHODS

This is a double blind, placebo controlled trial in 14 women with ovulatory menstrual cycles and maximal aerobic capacity (VO(2)MAX) >/==" BORDER="0">50 ml/kg/min. Four measures of athletic performance were tested: VO(2)MAX, anaerobic capacity (anaerobic speed test), aerobic endurance (time to fatigue at 90% of VO(2)MAX), and isokinetic strength (Cybex II dynamometer). Height, weight, and six skinfold measurements were also recorded. All these observational tests were completed during both the follicular and mid-luteal phases of an ovulatory menstrual cycle. Cycle phases were confirmed by assaying plasma oestradiol and progesterone. Participants were subsequently randomly assigned to either a tricyclic oral contraceptive or placebo and retested in identical fashion (oral contraceptive phase).

RESULTS

Absolute and relative changes in VO(2)MAX from follicular to oral contraceptive phase decreased in the oral contraceptive group by 4.7%, whereas the placebo group showed a slight increase (+1.5%) over the same time period. Two of the women taking oral contraceptive had decreases of 4 and 9 ml/kg/min. In contrast, most women in the placebo group improved or maintained VO(2)MAX. There was also a significant increase in the sum of skinfolds in women taking oral contraceptive compared with those taking placebo (p<0.01). There were no significant changes in other physiological variables (maximum ventilation, heart rate, respiratory exchange ratio, packed cell volume) or measures of performance (anaerobic speed test, aerobic endurance, isokinetic strength) as a function of oral contraceptive treatment.

CONCLUSIONS

The decrease in VO(2)MAX that occurs when oral contraceptive is taken may influence elite sporting performance in some women. Further studies are required to determine the mechanisms of this change.

Menstrual cycle, contraception, and performance

Although understanding of the unique physiology of the female athlete has increased, there are still many questions to be answered. Endogenous and exogenous female sex steroids have been shown to influence various cardiovascular, respiratory, and metabolic parameters, but these changes probably have minimal impact on the ability of most recreational athletes to participate in and enjoy their sport. Statistically significant data may or may not have clinical or performance relevance. By the same token, a statistically nonsignificant change may mean the difference between first and second place to an elite athlete. For an athlete concerned about maximizing performance, individual variability in menstrual cycle changes to various performance parameters must be considered. It is difficult to predict how accurately controlled laboratory findings from a study population apply to an individual competitor on the playing field. Athletes taking OCs for contraception or for menstrual cycle control may be able to minimize any potential side effects and performance influences by taking the lower dose triphasic pills and the newer progestins. For women with menstrual dysfunction, OCs may provide a predictable hormonal milieu for training and competition. Further scientific study is needed using large-scale, prospective, randomized clinical trials on trained athletes and accurate hormonal measurements to determine the phase of the menstrual cycle to determine short- and long-term effects of cycle phase and OCs in exercising women. As more questions continue to be answered, physicians and sport scientists will be better able to guide women not only to maximize their performance but to ensure lifelong good health.

Effect of the different phases of the menstrual cycle and oral contraceptives on athletic performance

The female athlete, during her reproductive years, has a complex and ever-changing milieu of female steroid hormones, whether it is the endogenous variations in estradiol and progesterone of a regular menstrual cycle, or the exogenous synthetic hormones of the oral contraceptives. Both estrogens and progestins have individual, interactive and sometimes opposing physiological actions with potential implications for the exercising female. In retrospective surveys on the menstrual cycle and performance, from 37 to 63% of athletes did not report any cycle 'phase' detriment, while 13 to 29% reported an improvement during menstruation. The best performances were generally in the immediate postmenstrual days, with the worse performances during the premenstrual interval and the first few days of menstrual flow. However, this type of study has an inherent built-in bias, and is further limited by the lack of substantiation of cycle phase. Many of the women studied associated premenstrual symptoms, such as fluid retention, weight gain, mood changes, and dysmenorrhoea with performance decrement. Such factors have also been causally linked with an increase in traumatic musculoskeletal injuries during the premenstrual and menstrual period. Neuromuscular coordination, manual dexterity, judgement and reaction time for complex tests have been shown to be adversely affected in women with premenstrual syndrome or symptoms, but confounding variables may include nutrition status and blood sugar levels. In addition, not all women suffer to the same level with premenstrual symptoms. Fluctuations in many physiological functions occur throughout the normal menstrual cycle. Results of early studies are difficult to interpret owing to the small numbers of women studied, wide range of fitness levels, and variability in the definitions of cycle phase. Nevertheless, investigators did not document any significant changes in measures of athletic performance as a function of timing of testing during the menstrual cycle. Swimmers have shown a premenstrual worsening of performance times, with improvement during the menstrual phase and on the eighth day of the cycle. An increase in perceived exertion was noted premenstrually and during the early menstrual stage with very intense exercise. In cross-country skiers, the best times were recorded in the postovulatory and postmenstrual phases, prompting the recommendation that training loads be selected according to cycle phase to achieve maximum benefit. Investigations using estradiol and progesterone levels as a confirmatory index of ovulation have not generally found significant differences across the cycle in either maximal or submaximal exercise responses, although a slight decrease in aerobic capacity during the luteal phase has been reported.(ABSTRACT TRUNCATED AT 400 WORDS)