What about running a personal best on our periods?

By Carole Fuchs


Understanding how our menstrual cycle will transform our training experience and boost our performance is powerful. If knowledge is power, we will all be able to use our natural cycle to our best advantage!


I recently read that 54% of women said they stopped exercising as a result of their menstrual cycle. Today, I want to tackle a topic women usually do not talk about either because they feel embarrassed and uncomfortable about it or simply because of cultural taboo. Menstrual cycle and sport performance have been left behind in the studies of sports for a long time despite being such a fascinating topic.


In some parts of the world it is still a taboo to talk about a woman on her periods. However, I am now seeing more and more female athletes engaging into this discussion. The more we talk about it the better. Opening the dialogue will help us to turn it to our advantage and get beyond that feeling of just having to “deal with it”. Running allows us to learn more about the human body and using that knowledge to improve our daily life is empowering.


Too often many female runners just don’t prepare for their menstrual cycles or only anticipate the worse. We all tend to prepare for everything else but our period. In this article, I want to show that going through our menstrual cycle is not a sign of weakness, bad luck or loss of opportunity. Let's talk about our periods and try to understand the process so that we have a chance to increase our health and performance and perhaps more importantly boost our confidence.


Having an open conversation regarding this topic with our life and training partners and coaches is very important. Coaches need to be able to talk about it openly with their athletes. As a female coach, I personally consider menstrual cycle as part of my athlete’s training strategy. There are so many physiological and psychological factors triggered by our cycle and changes in our hormonal levels including: temperature regulation, blood composition, ventilation system, food absorption. If we ignore those, our training plan may well become less efficient and we may lose motivation. I will talk about this in the second part of this article.


Using my own experience and based on the research I made about this topic, I can say that there is a timing for female athletes to push themselves and a timing for easier workouts and rest. Playing with our menstrual cycle while adding a few small changes in our nutrition can definitely result in better health, happier training and enhanced performances. We may well gain those 2% increase in performance during our race day here rather than extra-training.



The hormonal rollercoaster: what is at play


Let me first summarise what is happening and give you a brief outlook about what is at play during our cycle.


Two main hormones are driving our full cycle: oestrogen and progesterone. We will analyse together what those two hormones cause along the way. This may give you a hint about how some us (I am talking to myself here) may be craving for chocolate at some point during their cycle.


To begin with, the average typical cycle duration is about 28 days. This is a text book situation, there are so many variations of menstrual cycles according to age, contraception method used and so forth but we can say that a cycle can range between 21 to 35 days.


One cycle can be divided into 2 cycles of 14 days:


  1. the first stage, called the early follicular phase when oestrogen and progesterone levels are low and

  2. the final stage called the mid-luteal phase when oestrogen and progesterone levels are high.


The 1st day of our period (menstrual bleeding) starts a cycle. Bleeding happens when those hormones’ level drastically drops (the signal for uterus lining). Ovulation happens in the middle of the cycle, it is called the ovulatory phase, when oestrogen levels are high and progesterone levels are low.



The trigger of those phases is the increase and decrease of our hormone levels. Those short-term, rapid changes in our hormones levels affect our training and performance (not to mention our daily life experience).


Just before ovulation, our hormones are at their highest gears and they reach peak level 5 to 7 days before your period starts. Most of our menstrual issues are happening here. Those 5 days are bringing all side effects known as pre-menstrual syndromes (PMS). After this peak level phase, our hormones are dropping again until day 1, menstrual bleeding, which is supposed to release us from our hormonal stress and breaking news make us almost like a man (hormone wise)! The world feels wonderful again.


Let’s keep in mind that when our hormones level is rising around ovulation phase and mid-luteal phase (just before our period starts), it may affect our wellness and performance both physically and mentally to various extends. This is NORMAL. If we understand this process better we can go through it with more confidence, change a few things and get that extra kick to improve training experience and the quality of our daily life. Here, being self-conscious about the way we feel is very important. Testing different methods and keeping a record will help to monitor it.


Now, let me ask you a few questions: have you noticed a drop in motivation, do you struggle with performance or experience tough workouts around the ovulatory phase (about 14 days after menstrual bleeding)?


My own experience shows a pattern:


  1. during ovulatory phase, I am really fatigued, it feels harder to run and I am often suffering from an overall pain in my breast hurting bad the first 4 km of any run. This is due to rising hormones, especially oestrogen. Funny story: this pain was even worse when I was over-eating soybean based food (huge tofu blocks, fermented tofu beans and soy milk all combined), stopping this drastically helped me to feel better.

  2. during the PMS period, I usually have 1 difficult training session and it get worse 2 days before my periods: the world is upside-down, constant fatigue, hard to wake up in the morning, my heart rate is not responding, I feel totally uncoordinated on the trails and technical ground, downhills feel miserable, I feel out of breath and I am slowing down. Who is recognising herself here?


Let me advise you one thing (be ready to a list of “do not”) before the start of my PMS, I am always telling myself “do not evaluate yourself right now, do not evaluate your body image or try to assess how you are doing, do not compare yourself and do not open Strava”.

Anything related to ourselves should be put aside until the end of our monthly “crisis of confidence”.


Now, how does all of this impact our performance as runners during training and racing (or simply moving and exercise)? Are we totally doomed when our periods are due for our big race day? Should we simply give up and wait?


Menstrual Cycle and Performance


I have been running the 2/3 of my life and I was racing as a professional triathlete and runner for over 10 years now. During my professional time and until quite recently, I have always been obsessed with my periods, feeling anxious about the fact that my periods may start on race day (when I was not a full time runner, I would simply avoid racing on my periods). This issue totally stressed me out, thinking that my performance will drastically drop once my periods starts and imagining that all the hard work invested in training will be reduced to just hoping to finish the race struggling with cramps.




Now, let’s think about Paula Radcliffe breaking the marathon record in Chicago in 2002 while suffering period cramps in the last third of the race! I always saw Paula as a wonder-woman and I was at the time simply tagging her in my super-human category. Paula is not an exception, we are also seeing many olympic level swimmers breaking their personal records on their periods despite abdominal cramps. Therefore, I decided to understand more about the physiology involved in this, sure thing Paula is still human. Is there some pattern to discover that could be serving us all?


Prime Time Performance


Let me start with this breaking news: we are physiologically stronger during our periods. The best performance window should fall on day 1 l of the 1st phase of our cycle (= menstrual bleeding). Guess what, the best time for training hard and racing is arriving with our periods and right after. Despite cramping, this is our best moment.


When our hormones are at their lowest level, it is the best time for personal records and power performance. I would never have thought that my prime time would be on the day my period arrived (plus a few days after). At this time, our body is consuming less energy than in our high-hormonal phase, our body temperature, ventilation system and carbohydrates absorption capacity are all back to standard rates. In theory, this gives us the opportunity to produce and gain more strength and recover faster so, on the paper, it should feel easier to train and race! Counter-intuitive, right? Of course, it is very variable among women and we all have our own stories to tell here but the good news is that we are not cursed having our periods on race day and it's perfectly healthy to exercise and perform with it!


As previously said, a lot of female athletes clocked their fastest time on their period. We can push ourselves better despite menstrual cramps but let’s keep in mind that this will be very hard or impossible to overcome for some of us. We can attenuate the side effects if we add nutriments to our food. It is important to work on those nutrition strategies in order to maximise our opportunity to enjoy our “prime time” cycle window. Some women are severely affected and will not be able to go through obviously and it would be recommended to rest. For those who can go through it, we often notice that cramps are bad at the beginning and if we just get out and move it finally gets much better. Being active is really helping to go through cramps and pain, again for women not severely affected. However, we should all watch out heavy bleeding leading to a considerable iron loss, and compensate as necessary.

As a note, I just wanted to stress that our performance indicators VO2max and lactate threshold remain the same during our complete cycle but performance is so much more than those indicators.


The Heroine Turned Upside Down


As already said above, the worse effects we can experience during a cycle are usually happening during our hormone’s peak levels:

(1) just before ovulation and

(2) 5 days before menstrual bleeding (1st day of our periods).


The sudden change and increase in hormonal levels have tremendous subtle effects rarely developed in the studies of sports but of prime importance, especially for sports women. Besides our monthly “chocolate crisis”, change in our mood, drop in confidence, abdominal cramps, bloating and all the well known downside linked to PMS, you may have noticed a reduced aerobic capacity, which means that exercise feels harder.


Let me know if this is talking to you and if you can identify the following changes:


Craving for certain food? Have you been hoarding all the sweet snacks? Then, you are like me. This is due to a change in our metabolism and fuel system. During higher hormonal levels and PMS phase we experience a 10% increase in our metabolism, this makes us hungrier (for a good reason)! Our body will need to absorb more carbs as our hormones will make it harder for our body to assimilate them. Now, if you are craving for food, it is normal and this is our body reminding us to keep feeding the system.


Trouble to handle the heat? If you live in Asia, especially southeast Asia, you may have noticed that it is harder to handle the heat. This is again linked to a high level of hormones, especially progesterone causing an increase of our core temperature (by more than 1 degree) and as our blood volume is also affected, it can be causing heat strokes way quicker. You have to think about getting extra hydration and mineral intake during this time, especially if you live in very hot and humid countries.


Headaches? If you suffer from headaches, this is probably due to the shifting level of hormones and change of blood pressure before our period starts: watch your hydration. We usually lose about 8% of water in our blood and as a consequence our blood is a bit thicker. Same as the high-altitude climber, we will need to drink more fluid to facilitate our blood flow. Here, we are talking more about fluid containing electrolytes, especially sodium as we tend to lose more of this essential electrolyte during those phases. You can also add more salt directly in your food.


Feeling Uncoordinated? I always have trouble to get things right on the trails at this time and would avoid technical trails. During hormonal changes, we may suffer from a reduced coordination. Perhaps not the right time for mountain ridge running.


Hard to get out of bed? Feeling scattered? Again, high hormonal phase may bring fatigue and lack of attention: our hormones also affect those direct parts of the brain dealing with fatigue regulator but we can go through it with small changes, taking a few supplements like amino acids.


We can off set a lot of those side effects planning training according to our natural cycle, using nutrition and natural supplements and also hydrate correctly. Now, we have talked about the mechanism at play, I will talk more about action plans to make all of this smoother and more enjoyable in my next article.


I would advise women to keep a diary and study their training pattern. Adjusting our training to our natural cycle is essential to perform and enjoy the journey. Monitoring training this way can saves you precious time! It took me years before stating to train according to my menstrual cycle. Knowing this at an earlier stage could have saved me time, opportunities and avoid unnecessary time in the pain cave.