Female Physiology and a Fresh Approach to Endurance Training

Female Physiology and a Fresh Approach to Endurance Training

By Jasmijn Muller

Jasmijn Muller is a renowned endurance cyclist. In this short article she takes a break from training for the 7,400km NorthCape-Tarifa bike race to reveal how she is using her experience to help female athletes understand their bodies and train smarter. 

If you are a female amateur endurance athlete, I applaud you. Endurance sport is never easy, by definition. But in some ways you have it way harder than the pros. You don’t have the luxury of a fleet of nutritionists, physiologists and other experts supporting you. 

I know that long solo training sessions can feel liberating sometimes and lonely at others. And I know that when you are squeezing training around a career, a family and other commitments, you need your sessions to be as efficient and effective as possible.

But when it comes to finding those marginal gains, have you ever considered how fluctuations in hormones can affect your performance?

It starts with nutrition, with apologies to Warrington

Some lessons you learn the hard way. I first realised that I needed a more holistic approach to training while resurfacing the streets of Warrington with sickness and diarrhoea. (Apologies for that image.) I hadn’t paid enough attention to nutrition during an attempt at breaking the Land’s End to John o’ Groats record. My sports drinks were too hypertonic and not being absorbed. Having been in the saddle solidly since Cornwall, I couldn’t cycle another hour, let alone the remaining 400 miles. 

Women are more likely than men to experience gastrointestinal issues. This is most noticeable during the second half of the menstrual cycle, when rising levels of progesterone and oestradiol can cause more constipation, flatulence and bloating. Women also cannot absorb fructose as well as men. So, this is why you should be careful relying on gels alone for your training sessions. Gels are often high in fructose but can give a nice boost for shorter high-intensity sessions. 

Solid foods are tolerated better at lower training intensity. But even during an intense event like a long-distance time trial, I make sure solid food is part of the nutritional equation – such as a banana or a sandwich on white bread with the crust removed. What’s in your bottle should hydrate you, what’s in your pocket should nourish you. (Speaking of which, I genuinely cannot recommend Rawvelo’s natural energy bars highly enough.)

But nutrition is only part of the picture when it comes to endurance training for women. 


From the saddle to the surgical ward

When you commit a decent portion of your life to the sport you love, you don’t expect it to lead to labial surgery. Saddle sores are a common enemy of female cyclists – albeit an enemy that is under-discussed. For me, relentless hours in the saddle led to a recurrent problem with labial cysts. Golf-ball sized masses were removed surgically in 2013 and 2018. 

Post-surgery I was told that the cyst may have been caused by hidradenitis suppurativa (HS), an acne-like condition for which there is no cure. The symptoms include lumps in sweaty areas where your skin rubs together - such as armpits, groin, bum and breasts – and the advice is to avoid things like cycling. It was at this point, facing a forced exit from the sport I love, that I vowed to use food not just as fuel, but as medicine. 

Endurance training can be massively stressful and inflammatory on your body. The last thing you want to do is inflame it more by eating the wrong foods – chronic inflammation leads to illness and injury. I adopted a strict anti-inflammatory diet, removing sugar, yeast and processed foods. Everything that I consumed was as close to real food as possible. 

The tests on the cyst came back inconclusive. But since adopting a greater awareness about what I eat, I have yet to encounter further problems with cysts and saddle sores. Whether it was my nutritional choices or other factors such as doing exercises for glute imbalances or trying different styles of bike, the fact remains that plant-based diets can be massively beneficial for women with hormonal disruption.

It’s all about you. And your menstrual cycle. 

It’s easy to forget sometimes that each of us are individuals. You are as unique as your fingerprint. The way your body responds to training is personal to you. And the foods that fuel one body may have the opposite effect on yours. If you are serious about training more effectively, you must listen carefully to your body. Experiment with different nutritional approaches and make a note of what works and what doesn’t. 

As women we have a menstrual cycle that affects how our body behaves physiologically. For example, after ovulation, when progesterone levels are rising, core body temperature is elevated. That means you may struggle more with exercise in the heat at this time, because the sweat response is delayed. So, you have to be more on top of your hydration. 

The other challenge during the second half of the menstrual cycle is that oestrogen levels are also high. This result in a switch in your metabolism with women being even better than usual at burning fat, which is great for longer endurance events. High-intensity exercise, on the other hand, may be harder as your body also tends to conserve glycogen when oestrogen is high. So, you may need to increase the amount of carbohydrate you consume during high-intensity exercise a bit compared to when you are in the first half of your menstrual cycle.

All of these things can have a huge impact on your training, affecting everything from performance and energy levels to recovery. I asked myself how I could align training with what’s happening around my menstrual cycle, which led me to the book ROAR by Stacy Sims. It sparked a fascination with understanding female physiology in endurance sport – and taking a holistic approach to endurance training. 


Jasmijn Muller smiling


Helping women to be the best they can be

After everything I have learnt, coaching other women seemed a natural progression. The holistic approach I take with myself is the bedrock of my coaching technique, where my mission is to help women to be the best they can be. The narrative around saddle sores is changing and thanks to social media and online communities, women are being more open about their struggles in the saddle. Likewise there are a wave of apps that are empowering women to understand more about their menstrual cycle and track their symptoms from one cycle to the next to identify trends, even when periods tend to be less regular during peri-menopause.

My approach is to overlay nutrition and training onto the fluctuations in female sex hormones and the related symptoms you may experience. When your daily or weekly training sessions are built holistically, you can improve your performance and reduce recovery issues like DOMs. With some of my clients I also look into tailoring their training to their genetics. Then there’s the psychological side of things: helping people to stay mentally focused when their body wants to give up. It’s about making sure everything is fine-tuned for the individual. Apps and digital technology can support this fine-tuning process. 

Historically the bulk of exercise research is based on men. Slowly we are starting to see more female specific research. This is exciting. 

But despite the rise of more female specific research, the key to training remains to look inwards and make your regime as personal to you as possible. To use the growing amounts of knowledge out there to discover what works best for you. It’s an exciting journey that’s full of possibility. But let’s make one thing luminously clear. If you ever feel like you can’t deepen your relationship with your chosen sport because of fatigue, cramps or any of the myriad physiological issues that we face as women, my message to you is this: you can. 

You can find out more about Jasmijn’s coaching at betheeggcyclecoaching.com