In recent decades, there has been a significant increase in interest in physical exercise among men and women. This interest can be seen both in occasional recreational practice and in the practice of competitive sports. For example, marathon running was always considered the panacea of endurance sports, as only a few athletes among the world’s elite were able to finish one. Today, however, thousands of marathons are held every year around the world, with hundreds of thousands of participants completing them one way or another—40% of these being women. This represents an increase of around 35% in female participation in recent years. Social changes, legislation, medical controls, and popular culture have helped to provide new and better opportunities for women to participate in many different sports disciplines. There is no doubt that physical exercise provides important health benefits; however, there is some concern that excessive activity may have negative effects on fertility.
Therefore, with a more active practice of recreational sports, and the increase in participation in both training and regulated competitions, it is necessary to evaluate the impact that this may have on reproduction.
Exercise is a highly beneficial activity for most women, which certainly improves their quality of life.
However, with intense physical activity, adverse effects may occur in relation to their reproductive capacity.
The physiological mechanism responsible for this seems to be the generation of a deficit of metabolic resources, which forces the body to have a catabolic reaction that optimizes the bodily systems necessary for maintaining health to the detriment of the reproductive system, thus resulting in a sterility that is easily reversible through the adequate replenishment of energy resources in a timely manner.
The main clinical manifestations include menstrual disorders, as well as ovulatory dysfunction and possible negative effects on oocyte quality. These negative effects are highly variable depending on the intensity, volume, and type of physical activity carried out. And so, in sports where one must carry their own weight, where thinness is given great importance, this is where there is a higher prevalence of fertility-related disorders. In some disciplines, such as cycling or swimming, it occurs less frequently, although twice as often as in the general population that does not practice intense physical exercise.
In this regard, there are numerous studies that show a higher prevalence of reproductive alterations among female athletes when compared to those who are not (or do not play sports). However, other studies show the importance of physical exercise aimed at lowering the body mass index in patients with obesity and Polycystic Ovary Syndrome PCOS), with higher success rates following assisted reproduction treatments, with a higher rate of embryo implantation, increased likelihood of pregnancy, and lower risk of miscarriage, among these patients. Also, in women with PCOS, reproductive function can be improved to the point of spontaneous ovulation, thus increasing the possibility of pregnancy without having to resort to reproductive techniques.
Another very important aspect to keep in mind is that the practice of high intensity sports among adolescents and young women may lead to different metabolic and psychological alterations of important clinical relevance. The most common manifestations are primary amenorrhea (no onset of menstruation during puberty) and secondary amenorrhea (they cease to menstruate), lower bone density, and eating disorders, such as anorexia, bulimia, or inappropriate dieting. The appearance of these three manifestations concomitantly is what has been called the “Athlete Triad”.
A lack of periods in adolescent athletes is a manifestation of the combination between intense physical exercise, a high degree of emotional stress, and/or decreased food intake. The short-term consequences may include infertility and, in the long term, osteoporosis.
The primary treatment goal for these athletes should be the prevention of any of the three components of the triad, by educating athletes, coaches, parents, and health professionals on the importance of proper nutrition and a safe training program. With the application of the appropriate preventive measures, the long-term prognosis is good; however, the occurrence of long-term alterations may present health consequences for these young people in the future.