IJCS | Volume 32, Nº4, July/August 2019

416 Colombo et al. Sudden cardiac death in female athletes Int J Cardiovasc Sci. 2019;32(4):414-417 Review Article hypertrophy and their activity seems to be higher in females than males. 24 Cardiovascular responses to exercise include increase in heart rate, blood pressure and stroke volume. In the presence of abnormal substrates, which occurs in individuals carrying silent cardiac diseases, the adrenergic surges during intense exercise may lead to life-threatening arrhythmias, and hence competitive sports can be a trigger to SCD. Data suggest a higher sympathetic and/or a lower vagal activity in men compared with women. Markers of sympathetic activation after an orthostatic challenge were reported to be higher in male athletes than in females. 25 Thus, it is plausible to assume that sympathetic predominance contributes to a higher risk for SCD in men. Recent studies 26-28 have demonstrated that veteran male athletes with lifelong high-intensity exercise may exhibit cardiac abnormalities such as coronary artery calcification (CAC), atrial fibrillation (AF) and myocardial fibrosis. These abnormalities have been described as possible deleterious effects of exercise and were rarely present in female athletes. Although a higher prevalence of CAC was observed in veteran male athletes when compared with sedentary males, such difference was not seen between female athletes and female controls. 26 Additionally, female marathoners showed a lower prevalence of coronary plaques and less CAC than sedentary women. 27 Regarding AF, studies including female athletes are few, but the 5 fold-risk of developing AF suggested in veteran male athletes has not been observed in female athletes yet. 28 Similarly, myocardial fibrosis has been described in veteran male athletes, but not in female athletes. A recent study on triathletes reported that 17% of the men but none of the women had late gadolinium enhancement in cardiac magnetic resonance. 29 Therefore, despite the small number of women studied, it can be inferred that females are protected from these complications as well. Conclusion The lower prevalence of SCD in women is a fact, but not well understood. The recent increase in women’s participation in high-level sports competitions raises the debate on whether this occurrence is a question related only to the number of women in sports. Female athletes exhibit different cardiac adaptation to exercise and different prevalence of cardiac abnormalities during lifelong exercise practice, including less CAC and myocardial fibrosis, both potentially substrates for life-threatening arrhythmias and SCD. There is a lack of data in humans, particularly in female athletes, but estrogens may play a role in these responses. Cardiac remodelling mechanisms depend on molecular and genetic characteristics influenced by hormones and seem to harbour the mystery of women not being the “fair sex”, especially for dying suddenly in sports competition. It is essential to expand the studies including female athletes to acquire better knowledge in this area. This understanding may improve the preventive actions for SCD in sports. Author contributions Conception and design of the research: Colombo C, Ghorayeb N. Acquisition of data: Colombo C, Garcia TG, Francisco RC. Analysis and interpretation of the data: Colombo C, Ghorayeb N. Writing of the manuscript: Colombo C, Ghorayeb N. Critical revision of the manuscript for intellectual content: Colombo C, Ghorayeb N. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This study is not associated with any thesis or dissertation work. Ethics approval and consent to participate This article does not contain any studies with human participants or animals performed by any of the authors.