Training and racing with the menstrual cycle
I have learned A LOT the last two years about training and racing with my natural menstrual cycle. I wasn’t going to write about this because I am not a medical professional, but several of my friends have asked my to write on this exact topic, so here we go.
The following information is about my experience the past three years with a natural menstrual cycle (prior to that I took the combined pill for 10 years). There is significant variation in how females experience their menstrual cycle. Levels of estrogen and progesterone vary greatly among healthy females, which effects how each phase of the menstrual cycle is experienced. Perimenopausal (usually women aged 40-44 but can begin in 30s) and post-menopausal (menopause is the date at which there has been 12 months since the last period, again this happens at very different times for all women, but generally between the ages of 45 to 60) females have different hormonal patterns and will also have different experiences with how hormones effect their athletic performance. If you are in the peri or post menopause age groups I highly recommend you read Stacy Sims book ‘Next level’. This will be much more relevant to you than what I write here.
Most hormone based contraceptives also effect the menstrual cycle so this information may not be relevant to woman who use contraceptives (with the exception being the IUD which releases hormones locally and may not affect the natural menstrual cycle, but can so very case by case dependent). The duration of menstrual cycles vary significantly among individuals with 21 to 35 days considered within the normal range. For simplicity I have I have broken the menstrual cycle up into four parts and used a textbook 28 day cycle.
Early follicular Phase (menstruation) – days 1-7
What hormones are doing
The follicular phase start on day one of the period. The period occurs because the egg released during ovulation has not been fertilised, and the thickened uterus lining is shed so that the body can then recover and build up for the next round of preparing for potential pregnancy. The body’s goal in the follicular phase is to be healthy enough to mature an egg to release during ovulation. During days 1-7 estrogen and progesterone are at the lowest levels and women are the most like men than at any other time in the menstrual cycle.
One thing to note for females tracking their cycle length is that it is usually the follicular phase that lengthens or shortens to create an overall longer or shorter menstrual cycle. This is because the body will delay release of estrogen and LH if it is not healthy enough to mature an egg. The follicular phase may lengthen if you are in heavy training, in energy deficit or have been sick ect, as the body tries to recover enough to support a potential pregnancy. For me, if I am healthy and have a low training load I usually sit at a 28 day cycle. When I am doing higher volume or a lot of high intensity training my cycle will lengthen to 32 days or more. Importantly, I still have my menstrual cycle including experiencing normal hormonal fluctuations for me, and I make sure I am fuelling myself adequately, but just to note that it is not unusual for female athletes to have cycles of varying length throughout the training year. These variations in length are telling your important things that you should be paying attention to.
Impact on athletic performance
Low estrogen and progesterone levels create a perfect hormonal environment for strong athletic performance. However, women who experience significant period symptoms will likely not feel great during this time until these symptoms pass. During this low hormone phase, the female body is primed for performance. It is easier to lift heavy things and work at higher intensities. Core temperature is lower and there is more water in the blood leading to greater blood plasma volume for circulation and sweating. Access to stored glycogen is better and females do not rely as much on amino acids for fuel (versus luteal phase where amino acids are relied on more heavily and utilising stored glycogen is more difficult). Recovery from training is also much faster, meaning you can push a bit more in sessions because you can be confident you will recover that little bit easier than in luteal phase. This is a great time to do time trials or tests because your heart rate, respiratory rate and ability to use and access stored carbohydrate is ‘normal’ and you are primed for performance. Stacy Sims suggests that even for women experiencing significant period symptoms in the first few days of their cycle, doing very small doses of high intensity exercise (such as 6x20s efforts) will not only assist with period symptoms but also prime the body over time to have a less inflammatory response to menstruation for future periods.
On a personal level, I find it hard to perform well on day 1 of my period because the localised inflammation makes me need to stop constantly for the bathroom and it is a bit uncomfortable. I can make these symptoms disappear by using NSAIDS but I usually try and avoid taking these tablets unless I really need to perform perfectly. Usually by day 2 I feel amazing and from then on will try and optimise training by pushing that bit harder in high intensity training sessions if I feel like it, knowing that I am going to recover very quickly. I also add extra strength training. I find it is fairly easy to use stored carbohydrate (you can actually feel this by how quickly you fatigue or need to refuel versus the luteal phase) and recovery is great, so I don’t do anything special here for nutrition. I do resume iron supplements which I stop taking in the late luteal phase as I find the inflammation effect does not match well with iron absorption.
Late follicular Phase – days 8-14
Theme song: Unstoppable by Sia
What hormones are doing
Around day 7 of the follicular phase, follicle stimulating hormone is released. Estrogen levels start to rise and a luteinising hormone (LH) is released. I like to call this the superhuman phase because this is when I find I am absolutely ready to crush any kind of athletic competition (discussed in more detail below). This is one of the absolute best parts of being female and far outweighs the not so good parts of the late luteal phase. The release of LH eventually leads to ovulation which is when a mature egg is released into the uterus.
Estrogen is absolutely essential for female health. In particular, the estrogen surge in the late follicular phase is crucial for gut health, brain health, building lean muscle mass and being able to easily store and use carbohydrates. The presence of estrogen in the follicular phase (in combination with other hormones) is one of the reasons why building muscle and peak performance come much easier during this phase. Women who for any reason are not experiencing this estrogen surge (i.e. because they have lost their menstrual cycle) may find they experience a rapid decline in health, inability to build muscle, inability to recover and potentially also GI issues.
Impact on athletic performance
If you enjoy training in days 1 to 7 just wait until the estrogen increases in days 8 to 14. I find this phase is even more optimal for peak performance than the early follicular phase. Estrogen increases in the second half of the follicular phase so the body can store more carbohydrate to use for developing the potential foetus. However, it also has an awesome effect for sports performance in that you can better digest, store and access the carbohydrate needed during this time leading to better endurance performance at all intensities. The estrogen surge also has the effect of making skin look smooth and the neurotransmitters involved provide a boost in confidence. There is also a minor spike in testosterone right after ovulation. For me, I really notice that suddenly I feel assertive and it is easy for me to perform aggressively in racing and training in the four to five days prior to ovulation. The estrogen also helps create a cognitive boost, and I often find I am thinking very clearly and smashing it at work during this time. Some females report feeling average on the actual day of ovulation, but still experience the confidence and performance benefits caused by the estrogen boost prior.
Early luteal phase – days 15-21
Theme song: Work by Rihanna
What hormones are doing
After ovulation estrogen initially drops while progesterone starts to rise. Progesterone breaks things down to provide ‘building blocks’ for the uterus to support the potential pregnancy. This is a catabolic process where lean muscle mass is broken down to use as fatty acids for various purposes. Glycogen is also pulled from the muscles to use in the uterus lining. The body is working hard to provide conditions to support a potentially fertilised egg.
Impact on athletic performance
I find the first five to seven days of the luteal phase are good, only noticing the decline due to the contrast of feeling super amazing during the late follicular phase. Training during this time is generally good though recovery is a little slower. For me, it is usually a solid but not overly amazing seven days of training. Just getting that work in over and over, often not being particularly excited about it. Not particularly awesome but rocking up every day regardless. I know some women who feel particularly terrible just after ovulation due to the sudden drop in hormones. I don’t experience this at all.
Late luteal phase (pre-menstruation) – days 22-28
Theme song: Your choice of Adele
What hormones are doing
In the second half of the luteal phase, progesterone continues to increase. Estrogen also increases but progesterone dominates. Progesterone levels peak about five to six days prior to menstruation. If no egg is implanted, progesterone and estrogen levels drop fairly suddenly causing a huge inflammatory response. This can make it very difficult to recover from training, and is often experienced alongside water retention which can make women feel or appear puffy. It is normal for weight fluctuations occur throughout the menstrual cycle, and the late luteal phase is usually the time when weight can increase 1-2kg due to the inflammatory response and water retention. If monitoring weight (which I don’t recommend at all) it is important to understand that weight will likely increase in the late luteal phase and then decrease to normal in the early follicular phase. This is normal and a healthy response to the change in hormones.
Every system in the body is affected during the late luteal phase. The body cannot use carbohydrate very well and to hit higher intensities women need a higher percentage of carbohydrate in their diets. This is also to account for the increase in metabolism. Women burn 150-200 additional calories a day in the late luteal phase. As the body cannot use carbohydrates as effectively it relies more heavily on amino acids. Women have a 12% increase in protein needs during this time, meaning that women need to eat protein at regular intervals throughout the day to keep amino acids circulating. Women may also experience sleep disturbances caused by a higher core body temperature. Sleep disturbances can also be caused by low blood sugar levels.
Impact on athletic performance
The late luteal phase is not great for athletic performance. High progesterone levels cause:
• higher respiratory rate
• higher resting heart rate
• decrease in heart rate variability
• increase in core body temperature.
These factors make it difficult to sleep and train. Achieving any high intensity output is also more difficult due to these factors plus the difficulty utilising carbohydrates. When training during this time it is important to eat small amounts of complex carbohydrates throughout the day along with protein sources that are high in leucine. As the body is more heavily reliant on amino acids, the increased protein intake is essential to remain fuelled and help prevent muscle breakdown. The small amounts of complex carbohydrates will ensure a steady release of glycogen into the blood stream at a time when it is difficult for the body to access stored glycogen. During longer endurance efforts, women may also need to take in more carbohydrates due to the difficulty in accessing stored glycogen. It is a fine balance though, as progesterone levels can also effect digestion, so gastrointestinal distress is also more common in this phase. Women may want to look into using gels with amino acids in them if doing long runs or racing in this phase.
Entering the last few days of the luteal phase, the rapid drop in progesterone and estrogen causes a significant inflammation response in the body. I really experience this inflammatory response and day 24 or 25 is usually the worst for performance for me as my heart rate is the highest, I have trouble sleeping and I cant seem to recover no matter how much I dial in the nutrition. When describing the feeling to males I equate it to the feeling of living at sea level then being taken directly to 3,000m and having to do a training session. You will feel at least 10% less fit as your heart rate and respiratory rate increase and you have disrupted sleep. In addition imagine you are puffy from inflammation and cant recover from anything.
There are supplements you can take to help the body function in late luteal phase (B complex, zinc, fish oil), but in my experience while they help a little, your body is working against you in these few days. In my view it is more important to direct your attention to consuming complex carbohydrates and protein rich in leucine throughout the day. During this time I might do a four day deload or if continuing normal training acknowledge that it is going to be hard, I will need more recovery and that a subpar performance does not mean I have lost a truckload of fitness overnight. I usually back of strength training too and focus on rehab exercises and recovery. It is only four days and when follicular phase starts I am doing extra strength training to make the most of optimal conditions for strength and muscle building.
Competing at Triple Top 2022 in late luteal phase AND with a nasty virus (not Covid). Really difficult to perform well.
True Grit NSW 2022 which I raced on day 26 of my cycle.
What about racing?
Stacy Sims is adamant that there is never a negative day in the cycle for performance because the psychological can supersede the physiological. While I agree that a strong psychological game is key, in the last few days of the luteal phase, biology is working against women effecting their ability to perform well let alone reach peak performance. If a big race falls during this time, it really sucks because hormones do have a big impact regardless of how hard you try to mitigate the effects.
I definitely find it a lot more difficult to perform well in the luteal phase and particularly days 24-28 when I cannot hit usual performance metrics. It can be really frustrating when you have been training for a race and then performance is hit by a 5-10% (I have picked these percentages based on my own metrics and experience, it is not science) decrease due to timing with the menstrual cycle. It requires a lot of confidence to be comfortable to compete at this time. Your female competition might be at an optimal time for performance when you are in late luteal phase. They might not even have a healthy menstrual cycle. They might be on contraception that dampens the effects of late luteal phase. So it’s not even a case that while you might be effected this race, your competition will have their turn at some other point in time. You just have to be comfortable with what it means and do the best you can on the day. For me, the benefits of having a healthy menstrual cycle with normal hormone fluctuations greatly outweigh the negatives. It is still super hard when racing in late luteal phase.
Looking at it mathematically, there are five days in each menstrual cycle (for me) that are not great for racing. Just say my cycle is 32 days, there is a 15% chance that a race will fall on a day where optimal performance is very difficult (if not impossible). This doesn’t sound like a very high percentage and if the world worked in a fair way, there would be an 85% chance a race would not be in these five worst days for performance in the late luteal phase. However, in real life these percentages don’t always work out. In 2022 over half of my races fell in late luteal phase, including:
1. True Grit NSW – 25 June 2022
This 10km OCR race was tough because I had a small knee injury, it was one of my first races back from my broken foot, and I also competed on day 26 of my cycle. The knee injury was really a niggle but it wasn’t able to heal at a normal rate in the preceding couple of days because of the whole body inflammation experienced in late luteal phase. I also came into the race very tired and stressed and did not consume adequate extra carbohydrates in the lead up or before the race. When competing in late luteal phase you really need to come into the race very well rested.
2. Spartan Gold Coast Trifecta weekend – 15-16 October 2022
Having learned from races earlier in the year where I was competing in late luteal phase, I knew to come into the race well rested. I managed this a bit better and was able to compete relatively strongly, but did not consume enough carbohydrate during the race. In a Spartan Beast you are relying heavily on stored glycogen, which the body cannot access as readily in late luteal phase, so I should have been making sure I was consuming enough fuel to keep blood sugar levels up. Although I did try with my mental game, I psychologically wasn’t able to push as hard as needed (noting also that pushing hard is more difficult in late luteal phase when you have a higher heart rate and respiratory rate and high inflammation levels). There were several times in the race where I would have made a move to overtake to lean into my strengths (such as on the long uphill), but did not, and was also not aggressive on the downhills. Some of this can be attributed to this being my first Beast in Australia in over two years, but mostly it was the effects of being in late luteal phase. In addition, my recovery overnight was super slow due to being in late luteal phase. This meant that a tweak I picked up in my hip flexor did not heal overnight and I could not race the next day due to the limping and pain. When I got my period two days later this tweak fixed itself almost immediately. The timing of hormone changes in a menstrual cycle can be brutally unfair. If my cycle had been a couple of days earlier I would have recovered normally and been ready to race the next morning. Trifecta weekends and back to back racing is particularly difficult in late luteal phase due to the recovery being very slow.
3. Triple Top skyrace – 13 November 2022
For this race, in addition to being on day 27 of my cycle, I also had a virus (not Covid) and it rained torrentially the entire race. It is a bit difficult to allocate what contributed to this race being crazy difficult the most, possibly the virus. I rested extra before the race and consumed enough carbohydrate during the race but still could not beat the effects of late luteal phase combined with racing while sick.
Late luteal phase is also not great for training either, but its important to still do those long runs to experience what it might be like in the (very possible) situation you have to race during late luteal phase. In January 2023 I did the main range loop at Kosciuszko National Park as a long run on day 26. The high heart rate and respiratory rate in late luteal phase is exacerbated at altitude and I am grateful main range loop is so scenic so that it was still enjoyable. The following day on day 27 of my cycle I competed in the Crackenback Challenge, which is a short race the follows underneath the Kosciusko Express from Thredbo Village. It is very hard to work in high intensities during late luteal phase, but I love running uphill and I knew in advance it would be difficult. I still managed to have a solid performance and great time. My experience is it is much easier to make adaptions to continue training through late luteal phase than trying to hit peak performance for racing.
Summary
Being female is awesome, and most of the time the phases of the menstrual cycle support athletic performance. What I hope women take out of this to understand that hormones play an important role in athletic performance. By understanding what phase of the menstrual cycle you are in and the potential implications this might have for performance, you can better understand how to optimise performance and get the most out of yourself. Training might be going very well (late follicular phase) in which you can lean in further, or not well at all (late luteal phase) where you might want to alter training slightly, emphasise recovery and introduce some nutritional interventions. If a race looks like it will fall in late luteal phase, it is important to identify this in advance and come up with an appropriate taper, and nutrition and race strategy to suit.
Further reading
These are some great resources to start with:
• Stacy Sims – ROAR: How to match your food and fitness to your unique female physiology for optimal performance, great health and a strong, lean body for life.
• Stacy Sims – Next level: Your Guide to Kicking Ass, Feeling Great, and Crushing Goals Through Menopause and Beyond.
• Australian Institute of Sport Education Modules – Female Performance and Sport Initiative https://www.ais.gov.au/fphi/education. So many good modules (Normal menstrual cycle, Menstrual abnormalities 1, Menstrual abnormalities 2, Contraceptives for female athletes, Myths – facts or fiction, Nutrition for female athletes, Low energy availability).
• Claire Badenhorst – PhD and researcher focusing on womens health particularly female physiology, the menstrual cycle, iron status, and low energy availability. Find her on Instagram @claire_baddy (also search podcast episodes where she has appeared as a guest)
• Dr Izzy Smith – endocrinologist specialising in female athlete and hormone health. Find her on Instagram @doctorizzyksmith (also search podcast episodes where she has appeared as a guest)