Most running blogs, forums and books out there are written by boys for boys. But wait! What about girls? To balance things out this post is dedicated to all girls who enjoy running, and want to be in great shape throughout their training! 

So let’s begin with an interesting question: what do girls and training plans have in common? They both follow a cycle! 

Most training plans, like the ones posted in this website, are based on a cycle of four weeks. During the first three weeks, the intensity of the workouts increases week to week. In the fourth week (which I usually call the recovery week), the frequency and intensity of the workouts decreases, to allow the body recover and absorb the training stimulus. 

Women also follow a cycle, the menstrual cycle, that usually lasts between 24 and 38 days (Fraser et al. 2011). The menstrual cycle starts with the first day of the period and ends when the next period begins. Assuming an average 28-day cycle, the following figure not only shows the hormone variation during the cycle, but it also shows how the menstrual cycle can be coupled to the training cycle for optimal performance.

Each menstrual cycle starts with menstruation (the period, that on average lasts about 5 or 6 days), and follows two hormonal phases, follicular and luteal. While in men testosterone concentration exhibits minor variations in a daily basis (being on average ~6-10 ng/ml), in women estrogen and progesterone exhibit cyclical peaks. Estrogen peaks at approximately 0.2-0.3 ng/ml at day 12 of the menstrual cycle (during the follicular phase) then drops to approximately 0.1-0.15 ng/ml during the early luteal/ late follicular transition. A progesterone peak of 8-10 ng/ml occurs at approximately day 20 of the cycle and is coupled with a concurrent rise in estrogen to approximately 0.15-0.2 ng/ml (during the luteal phase) (Bowen et al. 2011, here ng/ml refers to nanograms per millilitre).

Menstrual cycle is then characterised by the different concentration of estrogen and progesterone hormones, but so what? why is that important? Because hormone variations trigger physiological changes that can affect exercise performance (e.g. Priyadharshini et al. 2017; Cristina-Souza et al. 2019), to the extent that some studies recommend female athletes to base the periodization of their strength training on their individual menstrual cycle (Sung et al. 2014).

In my personal experience, my menstrual cycle affects my performance, recovery and even mood! So understanding where I am in the cycle helps me plan my training accordingly. My rule of thumb is to place the recovery weeks of my training (named week 4 in the figure) to begin a few days before my period, when I tend to have very annoying menstrual pain. Note, however, that this is very personal. We, ladies, are not all the same, and many studies have also shown that the best time for optimal performance comes around the first day of our period, when hormones are low. Although it does not work for me, it works for other girls. Let me tell you an excellent example, Paula Radcliffe set her first marathon world record at 2002 Chicago Marathon, on the day her period started. 🙂

In the figure above, week 4 is placed a few days before the start of the menstrual cycle, and therefore week 1 lies during the mid-follicular phase. Between week 1 and 2 the level of estrogen peaks. As estrogen rises, our body will tend to conserve glycogen store and utilise fas as fuel, making it beneficial for extended endurance activities (Fischetto & Sax 2013, Barker & Sargent 2018). But also, our body will be more insulin sensitive, gaining more pain tolerance (Price et al. 1998). As a result, these weeks are excellent for us to focus on high-intensity anaerobic conditioning and prolonged endurance exercises. 

During Week 3, in the luteal phase, both estrogen and progesterone levels peak, causing blood to become thickened, which itself results in slower blood flow between muscles. As a consequence, we will need longer recovery times between high-intensity workouts due to restricted oxygen delivery (Barker & Sargent 2018). During this time is then better to reduce anaerobic training, and focus on aerobic efforts, like steady-state runs.

I hope this post helps us understand our complicated body a bit better! I learnt a lot while researching on this topic, and my conclusion at the end of the day is the following. How we feel throughout our cycle is extremely subjective. For that reason we not only need to be patient and learn what our bodies are telling us (hence this post), but more importantly, we need to learn to listen to our body!

Happy running!

Camila

References

Barker, K. & Sargent, D. (2018) Strength and Conditioning for Female Athletes. The Crowood Press. ISBN 9781785004100.

Bowen, R.S.; Turner, M.J. and Lightfoot, T.J. (2011) Sex Hormone Effects on Physical Activity Levels: Why Doesn’t Jane Run as Much as Dick? Sports Med. DOI: 10.2165/11536860-000000000-00000

Cristina-Souza, G.; Santos-Mariano, A.C.; Souza-Rodrigues, C.C.; Osiecki, R.; Silva, S.F.; Lima-Silva, A.E. & De Oliveira, F.R. (2019) Menstrual cycle alters training strain, monotony, and technical training length in young, Journal of Sports Sciences, DOI: https://doi.org/10.1080/02640414.2019.1597826

Fischetto, G & Sax, A. (2013) The menstrual cycle and Sport Performance. New Studies in Athletics, 28:3/4, 57-69.

Fraser, I.S.; Critchley. H.O.; Broder, M.; Munro, M.G. (2011) The FIGO recommendations on terminologies and definitions for normal and abnormal uterine bleeding. Semin Reprod Med. 29(5):383-90.

Priyadharshini, U.K.; Kavitha, U.; Nirmala, N.; Latha, R. (2017) Assessment of Skeletal Muscle Strength, Fatigue and Respiratory Efficiency in Young Healthy Females during Different Phases of Menstrual Cycle, ECPB, DOI: https://doi.org/10.25040/ecpb2017.04.005

Sung, E.; Han, A.; Hinrichs, T.; Vorgerd, M.; Manchado, C. & Platen, P. (2014) Effects of follicular versus luteal phase-based strength training in young women, SpringerPlus, DOI: https://doi.org/10.1186/2193-1801-3-668