The Implications of Female Sex Hormones – A Review of Current Research

Many female climbers who contact us here at Lattice Training have concerns and queries about training around the menstrual cycle. This blog is here to address some of the most common concerns and provide guidance. As with all aspects of training, there are always individual differences. This blog aims to summarise the most current research and the experiences of our coaches and the climbers who train with Lattice Training.

It’s important to remember that no two days are the same and you should always expect some fluctuation in performance and motivation. Understanding the role of female sex hormones can shed light on these variations and help you better navigate them. This information may also be relevant to athletes of all genders, depending on their individual physiology.

Our goal with this blog is to help you make sense of these patterns and use them to your advantage, so you can optimise your training, enhance your performance, and achieve your climbing goals.

Hormonal Fluctuations

Before exploring the impact of hormones and strategies that may be useful to implement during the different phases, here is a summary of hormonal fluctuations during one full menstrual cycle.

• Day 1 of cycle = day 1 of period

• Cycle length = 21 – 45 days

• Phases of the cycle are controlled by fluctuating hormones

Although there are many hormones, some of the primary hormones that impact the menstrual cycle are progesterone, oestrogen, luteinizing hormone, and follicle-stimulating hormone. There are three phases where the levels of these hormones fluctuate. The first phase of the cycle is the Follicular Phase, which starts from day one of menstruation. This is where the lining of the uterus is shed. During this phase, hormone levels are at their lowest. The second phase is the Ovulation Phase, during which the egg is matured and then released. During this phase, there is an increase in levels of oestrogen and the luteinizing hormone. Finally is the Luteal Phase where the uterus lining is thickened in preparation for housing the egg if it were to be fertilised. During this phase, progesterone and oestrogen levels are often high. 

Sex hormone fluctuations, although directly affecting the uterus, have an impact across the body and the implications of these fluctuations don’t only arise during menstruation. This is because the hormones fluctuate greatly throughout the entire menstrual cycle. The menstrual cycle also responds to the individual’s environment, so factors such as nutritional stress can directly impact the menstrual cycle. Although the graph above provides a general summary of hormonal fluctuations, it’s also useful to remember that hormone cycles and hormone ratios for each individual will differ and can have a unique impact on an individual’s symptoms and experiences during the cycle.

Challenging Perceptions and Cultural Norms

Interestingly, expectation and perception play a big role in the experience of symptoms associated with the menstrual cycle. Menstruation has been historically shrouded in vulnerability, shame, and secrecy, especially in the context of the marketing and advertisement of hygiene products. There was even a complete ban on TV advertising for these essential products (set by the National Association of Broadcasters) until 1972. Armed with the knowledge that the expectation and perception of menstruation can significantly impact an individual’s symptoms, it’s more important than ever to shift this attitude to one that empowers women and normalises something that on average happens 515 times in a woman’s life!

But What’s the Impact On Sporting Performance?

For us as climbers, this is the big question and in truth (SPOILER ALERT!) there isn’t a definitive answer. However, in a study that investigated an athletic population, 93% of participants reported that they experienced some menstrual cycle-related symptoms and around 65% of athletes felt that these symptoms impacted their performance, especially on ‘game day’. This indicates that the menstrual cycle isn’t something that should be ignored. As climbers, we’re often faced with difficult decisions when it comes to deciding whether to rest, train, or get on a project/dream line, and having a better understanding of your cycle might just provide that missing jigsaw piece. Unfortunately, research surrounding sporting performance and the menstrual cycle, historically, has poor methodology with inconclusive results. In the past, studies often had small samples and were based on one-off performances, rather than looking at performance over time. When these studies were reviewed in a systematic review, it was suggested that the quality of evidence was poor. As technology continues to advance, better, more rigorous research methods are emerging and there are some notable recommendations based on this research.

What Can We Take from the Research?

There have been several narrative reviews that included athletic populations only (with no comparison to a non-exercising population). A narrative review is a study that uses people’s individual life stories. These experiences are investigated and analysed to create a more broad, overall picture. Amongst narrative reviews, there has been a lot more agreement between studies and between individual experiences. The number of athletes reporting that performance outcomes were reduced was highest during the late Luteal Phase. However, athletes ‘felt’ like their performance was most impacted during menstruation (the early Follicular Phase) and the late Luteal Phase. In some ways, the latter suggestion may be more significant, because the way that performance is perceived can directly influence self-belief and result in actual change. Think placebo (or nocebo) effect. The symptoms most commonly reported were: cramps, fatigue, headaches, poor sleep, bloating, and mood changes (to name a few…).

There is a small number of studies that investigate the impact of training interventions over a full cycle (rather than just one or two days of the cycle). These studies took a polarised approach in their methodology, with groups of athletes that a) Completed strength training consistently across a 4-week cycle, b) Completed more strength training at the beginning of the cycle, during the Follicular Phase, and less in the Luteal Phase OR c) Completed less strength training at the beginning of the cycle, during the Follicular Phase, and more in the Luteal Phase. Although there were only a small number of studies, they all agreed that when strength training was focused around the Follicular Phase, this resulted in greater muscle mass and strength development. This led to the suggestion of a ‘gain then maintain’ approach to scheduling training. Another area in which the studies tended to agree was the impact that the menstrual cycle can have on injury risk.

Injury Risk

Many of the studies investigating injury risk during the menstrual cycle are within mainstream sports (such as rugby) with high-impact, change-of-direction movements. As a result, these studies look at the risk of lower limb injury. Well-supported within the literature is that an increase in oestrogen in the body leads to increased joint laxity (range of motion in the joint) and there is also a consensus within the literature that there is an increased risk of an ACL injury during ovulation (late Follicular Phase). Unfortunately, it’s hard to say whether the menstrual cycle would affect other areas of the body (such as the fingers or shoulders) in the same way.

Perhaps most importantly, athletes were at significantly higher risk of injury when menstrual cycle length changed over time, especially when cycle length gradually increased until cycles were fully missed. At the point when 3 menstrual cycles were missed was when injury risk was greatest. This is called anemrrohea and this is often attributed to Relative Energy Deficiency or RED-S. Because climbing is a weight-based sport, this can increase the risk of athletes developing RED-S. Further information on nutrition for female climbers can be found here. A simple way to monitor cycle length is to track your cycles.

Track Your Cycle

When tracking your cycle, it can be useful to make a note of how you feel during each phase. For many, it’s possible to see a pattern emerge and there may even be things that turn up frequently at certain points in the cycle. You may only need to track 2-3 full cycles to see that there are stages where performance could be optimised, although it’s advised to track your cycle for 3-6 months to better gain a bigger, more broad picture of your cycles over time. One of the main advantages of tracking your cycle is that it can help you to feel prepared, from knowing which sanitary products you might need to pack in your climbing bag to planning trips where access to facilities (shops, showers, toilets, etc.) may be limited.

It’s helpful to note down any significant dates, symptoms (cramps, bloatedness, etc.), and events (felt strong and sent the project, felt overcome with fear on a route, etc.). Subjective note-taking on the following can be informative: performance (actual and perceived), well-being, recovery, motivation, sleep, and energy. Again, the research is mixed regarding the impact of the menstrual cycle on cognitive function (the ability to regulate emotion, tolerate stres, and maintain attention/focus). However, this is something that our female athletes report their cycle impacting. Reflecting on your cognitive function during different phases of the cycle can also help you to plan ahead and think about which weeks you might want to use to optimise training and which weeks could be good to focus on projects or trips.

Some tracking apps come with push notifications and it’s worth mentioning that some of these notifications can feel unhelpful and may even exacerbate symptoms or trigger a placebo effect. That being said, some notifications can be informative. For example, notifying you that your cycle length was longer or shorter than usual. Only you will be able to decide whether having these notifications turned on is useful or detrimental when it comes to developing your own strategies for training.

Develop Strategies

When it comes to strategy, this is very individualised and will depend on the symptoms and experiences of an individual. For example, during higher hormone phases where the perception of performance may be low, it could be advantageous to replace a more complex, high-end projecting session with a simpler session that focuses on maintaining your aerobic base. Someone else may prefer to use this time to complete a basic weight-lifting session at a lower volume. These strategies need to be developed over time and with some trial and error.

Some suggestions include:

• Use RPE to gauge the intensity and set the intention of training during any given phase of the cycle.
• Schedule deload/reduced training weeks during certain phases of the cycle.
• Accept the challenge and detach from negative perceptions of symptoms. 
• Explore what feels accessible during the different phases.
• Let go of expectation or adjust the goal of a session so that it is process-focused (movement/technique development for example) rather than performance-focused (sending the project).
• Supplementation (seek guidance from your GP first).

Realistically, when planning a schedule, most climbers have to work around their career, their families, the weather/conditions, and their climbing partners. For some, the extra dynamic of planning around the menstrual cycle and hormonal fluctuations is one complication too many. For others, hormonal fluctuations may be the driving force behind all planning. Finding the path that works for you is ultimately the goal.

There is no ‘right’ answer, only the answer that feels right for you at the time. The growing body of research does provide some guidance, but every experience of menstruation is different. Whether the first day of the period is the green light to put in some big efforts or whether it signifies the need for some lower intensity work (or even rest), there are certainly ways for you to optimise your training during menstruation over the 35 years (on average) of experiencing it. 

Stay strong! 💪

Top Image © Pete Robbins

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