Sports Training & The Menstrual Cycle

Sports Training & The Menstrual Cycle

Sara Szabo holds a Master of Science in Exercise Physiology from the University of Alberta where she focused her studies on exploring the experience of endurance training throughout the menstrual cycle in runners. Her research interests stem from personal experience as marathon/ultra runner and cross-country skier. She is committed to creating positive, meaningful change in sport culture for girls and women. 

Note: the following article uses the term 'female' throughout. The author acknowledges the diversity of gender identities and recognizes there are many individuals who menstruate beyond those identifying as 'female'. For the purpose of this article and within the research referenced herein, the term female is used in reference to the hormonal and reproductive health experiences of those assigned female at birth. 


Research in Female Athletes 

Recently, we have witnessed a growing interest in female athlete health, particularly surrounding the menstrual cycle. This might be most apparent when scrolling social media or perhaps, in hearing personal anecdotes shared by athletes. Female reproductive health has not always been openly discussed in sports, or elsewhere for that matter. The seemingly worldwide momentum to increase and invite further conversation in this area piqued my curiosity and inspired me to contribute – in the best way I knew how – through research.

Training for sport performance is a physically and psychologically demanding experience which inflicts stress upon the body. It is therefore important for sport scientists and coaches to understand if a person is responding positively (adaptive) or negatively (maladaptive) to said stress. In exercise physiology, we refer to this as ‘training response’. This provides acute insight about how an athlete responds to the stress imposed by a given exercise session. 

For my master’s thesis, I wanted to understand how female runners respond to training across the menstrual cycle, as reproductive hormones fluctuate cyclically. I also wanted to do this in a way that might be realistically replicable in practice. 

Similar to a training diary, I developed an electronic questionnaire to collect exercise and menstrual cycle data on a daily basis. Athletes completed this survey daily for three consecutive menstrual cycles, providing enough time to identify any patterns across cycles. During each cycle, I asked them to confirm ovulation using at-home OVRY ovulation test strips. After the surveys, I conducted interviews with all participants to better understand each individual’s experience.

Research Takeaways

Some key takeaways from my work included the perceived value of the menstrual cycle and the process of cycle tracking. As a researcher in this domain and an avid endurance athlete myself, I spend a lot of time thinking and talking about menstrual health in athletes. Unfortunately, many sport cultures have supported a false discourse where losing one’s period is seen as normal, or even beneficial. This is both incorrect and dangerous. Therefore, I was encouraged to learn that “getting a period” was considered important among my study cohort. Participants said it helped confirm they were healthy and responding well to training. As the women reflected on their experiences of tracking exercise and menstrual cycle data, the responses were further encouraging. For most, this process helped improve self-awareness and/or confirmed pre-existing knowledge they may have had about their cycle. Additionally, some noted they engaged in more conversations about reproductive health as a result.

For one participant, the cycle tracking process actually helped to uncover a menstrual cycle irregularity – anovulation. Several unsuccessful attempts to verify ovulation using Ovry’s ovulation test strips, across two consecutive cycles, prompted a visit to her physician where her anovulatory status was confirmed, along with a diagnosis of low iron and low energy availability. 

What is relative energy deficiency in sport (REDS) or low energy availability – and what does it have to do with reproductive health?

Simply put, low energy availability (LEA) is caused by a mismatch between energy in (e.g., nutrition) and energy out (e.g., exercise or daily living). Insufficient energy intake has consequences whereby the athlete will be unable to support their exercise activity nor everyday body functions. If not addressed, LEA it can progress and lead to more severe concerns like relative energy deficiency in sport (REDs). Relative energy deficiency in sport (REDs) is a state of impaired physiological and/or psychological function that can occur among athletes. For further learning, experts in this area have recently published an updated consensus statement. 

Within female bodies, the menstrual cycle is a vital sign that offers insight about an individual’s hormonal health. For a long time, the complete loss of menstruation (bleeding) was regarded as the “canary in the coal mine” for identifying low energy available. However, ovulation is particularly useful for assessing energy availability and thus, experts now recommend ovulation testing as the best practice to monitor for LEA and REDs among female athletes. 

Cycle Tracking and Ovulation Testing for Athletes

Menstrual cycle tracking can be accomplished with relative ease. Although there are plenty of apps to facilitate this, cycle tracking can be done simply (and free of technology) using a calendar or pen/paper. Simply record the overall duration of the cycle, period details (e.g., duration, heaviness), and confirm and record ovulation. Noting menstrual-related symptoms such as physical and/or emotional changes that occur throughout the cycle is valuable. Some may also wish to track information such as basal body temperature or cervical mucus. These details can help to better understand individual reproductive health as well as support athletic experiences.  

First and foremost, cycle tracking can allow an athlete to predict, approximately, where within their cycle a competition will occur. With advance planning, this information can be integrated into training to ensure cycle symptoms, fuel/fluid preferences, expected sleep disturbances and overall psychosocial status are then approached strategically, helping to mitigate the additional and unnecessary stress of the unknown on competition day. My study participants shared that tracking their cycles made menstrual related discomforts predictable and often, more manageable as a result. This might not impact how an athlete chooses to organize their race schedule but it can certainly help them to feel more prepared and ready to perform.

Additionally, ovulation testing can help confirm healthy hormonal function. As previously mentioned, the use of Ovry ovulation test strips in my research study protocol revealed a case of anovulation and prompted a medical check-in. Without ovulation testing, the existing issue of low energy availability may have gone undetected for much longer. In this instance, ovulation testing truly offered an early warning sign. 

Therefore, it may be beneficial for athletes to specifically include ovulation testing as a method to confirm endocrine health. Expert practitioners and researchers at the Canadian Sport Institute Pacific (Victoria, BC) have even developed an ovulation monitoring protocol for their athletes, with a comprehensive explanation provided here. Now, some athletes might not be keen to follow this regimented testing protocol all the time. So, I suggest a few critical times when ovulation testing may be considered. First, during particularly stressful training blocks (e.g., higher volume) when greater energy expenditure risks disrupting the body’s energy balance. Second, consider ovulation testing if an athlete is displaying signs of impaired physiological and/or psychological function such as those associated with REDs. Finally, if an athlete has a prior history of disordered eating, LEA and/or REDs, testing to monitor ovulation may be a helpful and proactive strategy to ensure optimal reproductive health. 

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