The menstrual cycle: a marker of health and performance
10 Nov 2021

The profile of women’s football is currently rising rapidly, which is helping to boost women’s sport in general. According to Dr Ian Rollo (Gatorade Sports Science Institute), this phenomenon is a resurgence, as in the first decade of the 20th century, women’s football matches attracting more than 55,000 spectators were played in England. The success of women’s football was interrupted abruptly when the English FA banned it in 1921 as it was deemed inappropriate as, among other reasons, they alleged it could affect women’s reproductive capacity. This made other countries like Brazil follow their lead and an era when women’s football was forgotten began. In the 21st century, this reality took a 180º turn, and women’s football once again filled stadiums at international events, such as the last Champions League final in which FC Barcelona won the title.

The physiology of women and its implications in sports

Dr Anthony C. Hackney, professor of physiology and nutrition at the University of North Carolina, has talked about the physiological perspective of women. One of the main differences between sexes lies in sex hormones and their impact on bone, muscle and immune health. Steroidal sex hormones affect, for example, the perception of pain, mood or quality of sleep. This contrasts with the reality that for decades has prevailed in the world of research and performance, where women have been treated like “small men”. There is hardly any scientific evidence focused on physiological aspects of women.

Do oral contraceptives affect performance?

This issue is relevant because a large part of women who practise sports use contraceptives (about 50%), with the oral pill being the most used hormonal contraceptive. Does its use influence performance? Several recent meta-analyses presented by Dr Hackney show an apparently trivial reduction in performance women who take the pill. “Although a trivial decrease, these minor effects can be very important when considering that the difference between first and second place can be a mere 0.02 seconds.” Another important aspect is the opinion of athletes. Studies report that most believe both the menstrual cycle and oral contraceptives have an influence on their performance, which shows the need to continue researching and communicating continuously to advance the knowledge of female sports.

Health is the key to performance

Dr Nicky Keay (University College London, Durham University) has indicated that the menstrual cycle is an important marker of performance and health. If the cycle is regular, it indicates that the athlete has a good physiological condition. Cardiovascular, immune, hormonal and muscle systems are in optimal condition. Therefore, monitoring the different phases of the cycle, its duration, symptoms or bleeding should be an important part of preparation for female athletes. Having good communication and showing athletes their hormonal dynamics can help them improve training processes and their own health. As Dr Georgia Brunvels (University St Mary’s, London) says: “We have to empower and educate female players. They have to know how to take care of their own bodies by understanding their hormonal variations and how they influence their physical and mental states.”

Health is the key to improving performance

Good health is the basis on which to work with athletes, Dr Keay states. They have to be healthy to be able to perform. Female athletes should know that their performance is affected if they do not have optimal energy availability. Due to the high importance of this metabolic state, it must be a priority to identify it as soon as possible. Therefore, a nutritional approach and training load must be individualised and adapted to the hormonal profile of each athlete. This is relevant in all stages of life, since, in puberty, in adulthood and in the postmenopausal stage, hormone production is completely different, something that coaches and nutritionists should take into account.

Monitoring of physiological parameters in women’s football

Dr Beatriz Candás Estébanez of the Hospital de Barcelona has explained how FC Barcelona uses biomarker analysis to learn more about the metabolic and inflammatory status of the players. Some of the most widely used are testosterone, cortisol, testosterone/cortisol ratio, CK, glutamine/glutamate index or glycoproteins. In order to advance prediction processes, the club is conducting metabolomic studies to learn more about the players’ energy requirements.

If there is one field of knowledge that is revolutionising health and performance, it is the microbiota, the population of microorganisms that inhabit our body. Dr Ken McGrath (Microba), who has shown how athletes present greater bacterial diversity, has talked about this highly relevant issue and that its potential is still unknown, something that is related to performance. Thus, the use of antibiotics has shown in mice that it can affect bacterial health or how a genus of bacteria (Veillonella atypica) is related to an improvement in the ability to convert lactate into energy. Due to the importance of microbiota, Marta Llopis has presented myBIOME, a project that FC Barcelona has developed together with SYNLAB in which the metagenomic sequencing of the DNA of first team players’ faeces is analysed. The results have shown how, for example, 90% have optimal bacterial diversity, while 10% have reduced diversity.

Analysis of the external load in women’s football

If we consider the intensity of women’s football in recent years, the level of intensity has increased considerably. Dawn Scott, FIFA performance consultant, has shown how actions above 19 km/h are considered high intensity and what she calls “critical moments” in the game have increased by up to 30%. For this reason, she has expressed the need to expose the players to the intensity the modern game requires. They must design exercises that allow for the development of actions at this speed. In addition, exposing players to high work loads and maximum speed exercises could reduce the risk of injury. “Sprinting could act as a ‘vaccine’ for injuries.”

A new age in women’s football research

One of the main problems in the field of female sports knowledge is that hardly any research is done on female athletes. To alleviate this problem, Dr Antonia Lizarraga and Mireia Porta have talked about how FC Barcelona is studying more than 500 parameters in the female team (for example, Metagenomics, microbiome, variability of heart rate or sleep quality, etc.). One aspect that has been highlighted by Dr Lizarraga is the importance of sex hormones in performance and body composition, especially testosterone. This hormone is the main determining factor in the differences that exist in the levels of strength and muscle mass between men and women. This same relationship extends to stronger women: testosterone is a differential factor.

In relation to the low energy availability, the club has realised that dietary records are not reliable when detecting this status, since they have found that more than 90% of players report deficit values which do not reflect reality. Analysing the anabolic profile (e.g. dehydroepiandrosterone hormone) or aspects of body composition may help to optimally monitor metabolic status. In the case of the players of the first team, there have been no cases of relative energy deficiency.

A very interesting aspect that Dr Lizarraga highlights is the natural selection that is seen in elite football: a large number of female players have hyperandrogenism, which is related to higher levels of strength and coordination. Another important point is the monitoring of Vitamin D, a fundamental hormone in the immune and muscle systems, since a large part of the population and female athletes present deficient levels. Therefore, in many cases, supplementation is necessary to raise its concentration.

A practical approach to sports nutrition

How do different professionals work in the area of high performance? In the final part of the day, Lindsay Langford, from the US Soccer Federation, presented menus that she usually uses to facilitate the daily lives of the players: prepared salads, non-starchy vegetables, or foods with vasodilating properties such as beetroot. One aspect emphasised is the type of cooking, as she tries to make the dishes easy to prepare and healthy at the same time. In relation to supplementation, one “trick” she employs is to utilise a pillbox and a cupboard, from which she distributes various drinks and supplements, ensuring players don’t forget them in games and training.

Lloyd Parker, head of nutrition at Everton, has presented a case study that is part of the doctorate he is studying: monitoring the recovery of a player who suffered an anterior cruciate ligament rupture and who lost her period for 6 months after surgery. It has detailed the importance of body composition, calorie intake, energy expenditure and stress control to try to reverse amenorrhoea. According to Parker, perhaps the problem was not low energy availability, and instead was psychosocial stress derived from the proximity of the World Cup, something that made him see that the solution is not as simple as eating more and training less. Communication is key in these cases.

To conclude, there has been a round table discussion between the heads of nutrition at FC Barcelona Mireia Porta and Dr Antonia Lizarraga, and first team player Mariona Caldentey. As the player stated, in the past they were unaware of the importance of nutrition, it was common to eat fast food after training or games, and the implementation of an education programme by the club has radically changed their outlook. They know why they eat, what to eat and when to eat. Facilitating and simplifying the process in their day-to-day life has made many of them more interested in nutrition and motivated them to learn about its relevance to health and performance. Using visual strategies such as infographics has made them improve the quality of their nutrition.


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