New Research: Menstrual Cycle: The Importance of Both Phases and the Transitions Between Phases on Training and Perfomance
Sports Medicine. Current Opinion. April 2022
Bruinvels G, Hackney AC, Pedlar CR. Menstrual Cycle: The Importance of Both the Phases and the Transitions Between Phases on Training and Performance. Sports Med. 2022 Apr 29. doi: 10.1007/s40279-022-01691-2. Epub ahead of print. PMID: 35486372.
In this Current Opinion piece, the authors “share their applied experiences of working with female athletes in combination with the existing evidence-based literature.”
The purpose of the commentary was to demonstrate the impact of the day-to-day- fluctuations in menstrual cycle hormones on wellness symptoms and performance in female athletes. In addition, to raise awareness of the changes in hormone fluctuations between current menstrual cycle phases, and the importance of menstrual cycle tracking.
In this post, I will briefly summarize this article
Menstrual Cycle Phases and Changes in Hormones
Typically the menstrual cycle is split into two phases; follicular (day 1 of bleeding to day 14, ~ ovulation) and luteal (day 15 - day 28, the day before the next bleed)*. These two phases are split due to the differences in hormone levels where the follicular phase has lower estrogen and progesterone levels compared to the luteal phase which has higher estrogen and progesterone levels.
Simplistic illustration of two key hormones involved in the menstrual cycle; estrogen and progesterone and the hormone changes in the follicular phase, ovulation and luteal phase.
*This is a ‘text-book’ timeline and we know there is variation in the length of menstrual cycles among women.
What we do know is that the transition from follicular to luteal is not a steady increase in estrogen and progesterone. From the figure above, there are more transitional phases than just the two main phases mentioned (DYK it can be split into seven detailed phases!). But to keep things simpler, most commonly, the menstrual cycle is split into three: 1) menstruation (bleeding) where there are low sex hormones in the early follicular; 2) pre-ovulation where there is high estrogen in the late follicular and; 3) luteal where there is high estrogen and high progesterone. However, the fluctuations between these three phases are not linear and there are large changes with each hormone.
Two particular areas of interest for myself, and athletes alike, are the points in time before ovulation when there is a large increase in estrogen (and also a spike in luteinizing hormone, not pictured). And the other area is before the menstrual bleed, the pre-menstrual phase which sits in the late luteal phase. This latter area, along with menstrual bleeding, is a time where many individuals experience unfavourable symptoms such as cramping, pain, bloating, fatigue, back pain, changes in bleeding flow, etc.
Why Would Females Experience Pre-menstrual Symptoms?
It is all to do with the drop in hormones leading up to bleeding. There is a drop in progesterone that is paired with increased inflammation. The authors have noted that pre-menstrual symptoms have negatively impacted over 90% of individuals to some degree. Furthermore, “80% reporting symptoms or interrelated performance decrements every cycle… [and] 50-67% of elite athletes perceive their exercise performance to be disrupted by their menstrual cycle” (p. 2). However, the performance impacts on menstruating females are inconclusive due to the nature of data collection taken at set-time points in the menstrual cycle (e.g., early follicular). Personally, the anecdotal evidence I have gathered working with athletes is that the menstrual cycle does not impair sports performance, rather, it is the symptoms that make them feel a little off yet they can still have personal bests regardless of where they are in their cycle.
Call to Action
In the final section of this paper, the authors share the actions that can help the future of female athletes. To start, awareness and education for athletes and those surrounding them (parents, coaches, support staff, practitioners) about the menstrual cycle and the impacts that the cycle has on symptoms (and potentially performance) - enhancing or detrimental - needs to continue. A simple way to raise awareness and education is to have athletes track their cycles and log symptoms. There are some great apps that can help athletes understand their cycle, Wild.AI is one I personally use. This way, patterns of symptoms can be determined and interventions can be put in place where needed and based on the individual. Also, the way in which the menstrual cycle and symptoms are discussed should be in a positive light rather than detrimental: “empower, not limit” (p. 3). The more we can normalize these conversations the less ‘taboo’ they will become.
The authors admit that more research is needed “to provide data-driven insights into symptoms (frequency and severity), cycle length changes and symptom clusters as well as testing non-pharmacological, menstrual cycle phase-appropriate, symptom mitigation strategies throughout the entirety of the menstrual cycle.” (p.3). I fully agree with this statement. Hands up for new insights into the transitional phases of the menstrual cycle and understanding more of the impact on menstrual-related symptoms throughout the entire cycle. How you can help? Start talking and start tracking!