By Awesome Supplements, Read time: 8 minutes
One of the most common questions we get asked relates to how the menstrual cycle influences our nutritional needs. The intricacies of how the hormonal fluctuations associated with the menstrual cycle influence nutrition are fascinating, and anyone looking to work with a client who has one (or who has one themselves!) would benefit from checking this out.
Now, with that said the menstrual cycle doesn’t only influence nutritional needs, but exercise performance and training outcomes, too. While it may be the case that training is training and progress can be made without paying attention to this at all, there are benefits to paying attention to the biological details that can inform the way that you or your clients approach strength and endurance endeavours. This blog is here not to go into extreme detail on every facet of this topic, but instead to give you a brief overview followed by the important and actionable stuff that you can start doing NOW to get a better return on your time and energy investment.
Before we go into the actionable stuff let’s briefly outline what we’re talking about.
The menstrual cycle is a roughly 21-38 day process during which the level of various hormones within the body will increase and decrease in a predictable manner. The average is often considered to be 28 days or four weeks and so we will use this figure here but know that the range stated above is considered normal, and the number of days can fluctuate even within the same individual. For the purposes of today we will focus on the two big hitters – oestrogen and progesterone.
The entire cycle is based around reproduction, with ovulation occurring roughly in the middle and each cycle being punctuated by menstrual bleeding – the shedding of the engorged uterine wall – unless of course a pregnancy occurs. That is not to say, however, that fertility is the only thing that is altered from day to day or week to week across the cycle.
Instead these hormonal fluctuations can alter many other physiological states at different times of the month, based upon the level of each hormone, with some of these changes having important ramifications for exercise performance.
As mentioned, in an effort to keep this from being a 5000 word ebook, I’ll keep the mechanistic stuff short and on topic. So far as exercise is concerned), oestrogen seems to:
- Aid muscle growth and repair (1)
- Increase glucose availability and uptake into type 1 (fast twitch) muscle fibres (2)
- Increase glucose storage capacity in muscles (2)
- Suppress muscle catabolism (2)
Progesterone, on the other hand:
- Undoes much of what oestrogen does for muscle mass growth and repair (2)
- Reduces strength (3)
- Reduces the muscle developing effects of testosterone (4)
- Marginally increases metabolic rate and core temperature (5)
*Note that these data are from research in cisgender women. In cisgender men things are a little different due to the action of comparatively high levels of testosterone. Little data exists in this realm related to those using hormone therapy to transition
Read these points and then look at the diagram above – during the first half of the cycle (starting on day 1 of menstruation) both oestrogen and progesterone are low. As we progress towards ovulation, oestrogen rises incrementally, creating a situation where oestrogen is high, but progesterone is flatlined.
After ovulation, oestrogen dips then starts to rise again, while progesterone rises continually until the mid luteal phase, followed by a drop towards menstruation. As such there are four key times that are worthy of consideration:
- At day 1-7 everything is flatlined
- After the mid follicular phase, oestrogen rises until it peaks just before ovulation at day 14
- Between day 14, early luteal, and day 21, mid luteal, oestrogen is decreasing then rising while progesterone is rising
- And then between days 21-28 both are dropping back to baseline
*As noted, the specific durations of each stage may vary as not all cycles are 28 days
Because of all of these fluctuations in hormones that have important physiological functions, it’s no surprise that questions have arisen regarding how to plan training around the menstrual cycle; referred to as phase based training or periodisation.
The truth is not as clear-cut as one would expect, however, as results from studies are conflicting - some report worsened performance at certain times of the cycle, others do not (2). Some research has found significant performance differences at different times in the menstrual cycle, though, and there is a good mechanistic argument to say that results will be different, too. These findings have given birth to the idea of planning exercise programming around the menstrual cycle, with the key points being as per the following sections.
During menses and the first few days afterwards, both oestrogen and progesterone are low, and it’s here that most tend to find themselves feeling less motivated to train and, according to research by Gordon et al (6), less able to produce the same strength of muscle contraction (at least in the lower limbs). During this time the simple advice is to adjust to what you or your client are willing and able to do. Mood is often low, cramps are more likely, and strength may be reduced so looking to perform to a high level is likely to be wasted endeavour. Anecdotally, however, some feel stronger in this phase and so individual variation as always will trump generalisations, but for the majority it’s worth tracking the cycle and planning to take it easy during this time of the month. As a final note, it’s well documented that in female athletes, non contact related anterior cruciate ligament injuries are astronomically higher than in male athletes, and while the precise reason has yet to be pinned down - it’s almost certainly a combination of things, including specific anatomical differences between males and females, such as a greater Q angle, which is the angle between the patella tendon and quadriceps muscle along with hormonal shifts - almost all of the difference appears during the few days before, during and after menses (7). This means that those engaging in sports requiring rapid shifts in direction – think team sports like football, rugby, hockey and roller derby – may need to take additional care of their knees at this time. Strengthening the glutes, hamstrings, quads and core may reduce risk of these kinds of injury significantly.
Once menses has stopped, oestrogen starts rising in the absence of progesterone and with it, both mood and physical performance. This, according to a 2017 study, translates to increased progression due to an ability to create increased frequency and training volume (7). In that study, premenopausal women completed high volume and frequency training for either the first or last two weeks of their cycle, then only trained their legs once for the other weeks. After 4 months strength, power, and muscle size was increased either far more or only in the group that trained more during the follicular phase. This indicates that as soon as a client/you feel up to it after menstruation is done, it’s time for hard, heavy, and frequent training for the next roughly two weeks.
The end of the follicular phase signals ovulation (the time during which pregnancy is possible) and the peak of oestrogen. Theoretically, this would be the time to really push training and look to hit PB’s, but once ovulation has happened, oestrogen divebombs and starts rising again alongside progesterone. This, at least from a mechanistic standpoint, means that much of the beneficial effects of oestrogen are counteracted, and while most studies don’t find much of a difference, the one study that did (8), did indeed find that strength and muscle stability under load were compromised during the luteal phase. In addition to that, and in addition to the leg training study mentioned in the previous section, two earlier studies have found a benefit of increased training in the follicular phase (9,10), and the other remaining study on the topic found no difference (11), meaning that it seems at least some will be less capable of training maximally and with high volume during the luteal phase, though if indeed a difference does exist it absolutely doesn't seem to be ubiquitous.
As such, reducing training frequency and volume may be necessary for some in the post-ovulatory days. This will more than likely gel with subjective performance ability, too, with those who are more in tune with their bodies (again, tracking your cycle or your client’s cycle along with mood/recovery/performance is paramount) tending to find that how they feel in the second half of their cycle is different to how they feel in the first. The associated reductions in load or volume could and should therefore be led primarily by the client’s views or your own. More on this in the summary at the end of this blog.
One point of interest is that all of the studies that report a difference in strength or stamina between the luteal and follicular phases all used the lower body, whereas the difference does not appear when the upper body is trained. Again more on this in the final summary.
During the premenstrual days, oestrogen has decreased but progesterone is still elevated meaning that much of the physiological factors associated with the luteal phase are still in play albeit to a lesser degree. During this time the 4-8% increase in basal metabolic rate associated with the luteal phase progesterone levels will still be in play, but as oestrogen is dropping rapidly (often along with mood), cravings can start to mount up. Much like the first few days of the cycle, this is a time for your client (or you) to start paying attention to subjective wellbeing and take it easy if needs be.
Training progress is a long-term project, and taking it easy in the week around menstruation, thus allowing for proper recovery and self-care in preparation to really hammer it when the time is right, is likely to lead to better results over time than worrying about going hard every day.
In sum, as mentioned at the start, resistance training is resistance training. Ignoring all of this information and going to the gym 3-4 times each week with a plan for progressive overload, eating enough calories and protein, and getting a lot of sleep will get you results, but at the same time it’s important to listen to your body and respond accordingly to make sure you’re not wasting effort.
One of the best tools for those that find this relevant is a cycle tracker. This can be an app or pen and paper, but the idea is to track the day of the cycle then compare this with metrics like mood, cravings, sleep, gym performance, hunger, and so on. Track this and you may find no difference in gym performance which is great, but it’s likely that you'll find at least something, and as such it’s a good idea to plan to train in a manner similar to the below:
The week spanning 3 days pre menses, the day you ‘come on’, and the three days following: train as hard as you feel like it but be prepared for your volume and/or intensity to need to dip. Consider it a deload.
The following two weeks spanning from the early-mid follicular phase to ovulation: train HARD. Hit the weights, smash some PB’s and keep frequency high. Train lower body 2-4 times per week, and upper the same (consider 3-4 full body days, or an upper/lower split).
The final week after ovulation and prior to the premenstrual period: Continue as you were but be ready to back off on lower body training a little, hitting it 1-2 times per week. Upper body training can likely stay the same. Introduce some additional cardiovascular training if you feel like you need to drop lower body training but want to keep your activity levels the same.
And one more time, make sure you get enough protein! (1.6-2.2g/kg) (12).