Centre for Neuroscience and Cell Biology (CNC) and the European Project FOIE GRAS, coordinated by CNC, have been working closely with the organizing team of the European University Games 2018 in order to promote exercise practice and healthy living.
As part of this EUG2018-CNC partnership, the CNC researchers and the FOIE GRAS ESRs have written a series of chronicles that build upon the benefits of exercise practice on health.
These chronicles result from the collaboration between the Center for Neuroscience and Cell Biology (CNC) of the University of Coimbra, the European Advanced Training Network FOIE GRAS (http://www.projectfoiegras.eu), the Erasmus+ Program and the Academic Sports Federation University (FADU) in the scope of the European University Games Coimbra 2018.
These illustrated chronicles will be published in Portuguese at the local newspaper Diário de Coimbra and you can read here the English version on our website.
Exercise Practice and (In)fertility
When considering the good functioning of our organism, the almost universal advice contains two words: Equilibrium and Moderation. All the systems that compose who we are, from the brain to the reproductive system, need attention, and we can preserve our health throughout our lifetime by performing activities that promote well-being, for instance practicing exercise on a regular basis.
Human reproduction requires, besides the intention of the involved parties (and some physical activity…), a correct production of functional sperm and ovules, and a uterus in good conditions to implant and nurture an embryo. In turn, all these depend on the correct production of hormones, and on a healthy state of the organism (metabolic, nutritional, immunologic, etc.). In human (in)fertility, albeit in some cases the cause remains unknown (the so-called idiopathic infertility), there are obviously concrete causes (anatomical, physiological, hormonal, genetic) that explain difficulties in conceiving. But, what is the role of physical exercise in reproduction? As one can easily imagine, performing controlled essays with humans is not necessarily easy, if not for practical issues, for ethical ones. We don’t live in laboratories, we are all different and we have different daily physical activities, we can be advised but not forced to do certain activities; and above all, we reproduce by choice, not upon the researcher’s request. On the other hand, it is not only that the animals used in biomedical studies (namely rodents) might not be adequate models for the study of aspects of human physiology, but also that research regarding reproduction has not been a priority, unlike in the cases of, for instance, oncology, diabetes mellitus or neurodegenerative and cardiovascular diseases.
Leaving aside known infertility causes, human reproduction has been associated, in a very general way, to the global well-being of the organism (physical and psychological), which indirectly involves regular physical activity that need not to be necessarily intense. The (few) studies done at this level involve the use of questionnaires about exercise habits on different groups, as well as the study of the physiology of athletes, whose exercise loads can be easily monitored. Of interest, despite the use of questionnaires can bring reliability problems, in most cases, the unreliability of these studies is due to the lack of a “control group”, that is, a group of people with different types of lifestyle habits against which the athletes can be compared. On the other hand, in most studies the reproductive capacity tends to be analyzed indirectly and not as the main research objective.
Whatever the case, in the available studies the message is clear, moderate exercise increases the chances of conception (sometimes simply because it is related to sex frequency and a higher libido), and the reproductive quality (namely, sperm function), by reducing oxidative stress and increasing antioxidant defenses in the semen, especially in sedentary individuals. Alternatively, a chronic intense exercise regime, regardless of whether it is associated to high-performance competitions, can have detrimental effects on the reproductive potential, for instance altering the hormonal patterns or diminishing the libido in men, as well as reducing the concentration, morphology and motility of spermatozoids. On the female side, the available results are limited. Even though some of the studies suggest a beneficial (or at least a neutral) effect of exercise practice in women’s fertility, there is no strong direct association but only some indirect evidences such as those related to obesity; and even in those cases there is controversy. This remains an area that needs further attention, and a recent interest in this topic can be noticed by the high number of ongoing studies and the a large number of patients enrolled in them.
Another relevant subject in this context are the long-term effects of the use of substances to improve athletic performance in different modalities (the so-called “doping”). It is obvious that, given the illegal nature of these practices, there are not many controlled and systematic studies that allow to draw reliable conclusions, even if, at the end of their professional career, a countless number of athletes have revealed serious health problems that could be related with this phenomenon. These problems can affect the entire body, not only the reproductive system, and maybe the most popular example is the institutional “doping” promoted for decades by the old German Democratic Republic (GDR, or East Germany), and discovered at the end of the Cold War, after the fall of the Berlin Wall and with the reunification of Germany. That policy earned the GDR excellent sport results, particularly on the female side. Amongst the treatments used (in most cases without the knowledge of the athletes themselves), was the administration of the so-called anabolic steroids, including the “male” hormone, testosterone, to increase muscular mass. In addition to the problems related to mood and psychological disorders, some athletes reported later problems in conceiving, including an abnormal number of spontaneous abortions and alterations on the functioning of the reproductive system. These highlight once more the need for equilibrium and moderation, and the other important message in this context is that, certain activities (conscious or not) can have negative effects in the long run.
Author: João Ramalho-Santos is a Principal Investigator at the Center for Neuroscience and Cell Biology (CNC), University of Coimbra (UC), in Portugal and Professor at Department of Life Sciences of the University of Coimbra.
The project: This chronicle results from the collaboration between the Center for Neuroscience and Cell Biology (CNC) of the University of Coimbra, the European Advanced Training Network FOIE GRAS (http://www.projectfoiegras.eu), the Erasmus+ Program and the Academic Sports Federation University (FADU) in the scope of the European University Games Coimbra 2018.
Coordination: Anabela Marisa Azul, João Ramalho-Santos, Mireia Alemany i Pagès, Paulo Oliveira and Sara Varela Amaral
Illustration: Rui Tavares