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Cycle tracking is having a ‘moment’ among female athletes, probably due in part to the recent success of the U.S. women’s soccer team and their public acknowledgement of the role that this tactic played for them. The general idea is that there are predictable fluctuations in mood and behavior across the menstrual cycle, which may impact individual physical performance and/or team communication. People like Gabrielle Lichterman (the brains behind Hormonology), Stacy Sims (author of Roar), and Georgie Bruinvels (developer of the FitrWoman app), are leading the charge, encouraging women to become more familiar with their cycles as well as with a few basic ‘hacks’ for optimizing performance (in athletics and in life) across the various phases.
I’ve been tracking this myself for quite a while now — I lost my cycle for a few months following an aggressive weight cut in early 2018, which is what initially piqued my interest — so I appreciate this developing cultural conversation. As a woman and an athlete, I had a set of personal observations; as a medical provider, I had a set of halfway-scientific expectations; however, those two things often didn’t line up neatly. The learning process of the past couple years has been really interesting, and I do think there’s some degree of utility here, so figured I’d throw my two cents in.
It’s been known for some time that there are chemical changes in exercise metabolism across the phases of the menstrual cycle. The extremely simplified version is that we’re better at using carbohydrates for fuel during weeks 1 and 2, then comparatively better at burning fat in weeks 3 and 4. (The more scientific explanation is that estrogen promotes glucose availability, while progesterone is both glucose-suppressing AND more catabolic to muscle tissue.) While this isn’t necessarily something we ‘appreciate’ as 21st-century athletes, it does make complete sense from an evolutionary perspective: the ability to shift to a different effort mechanism in response to hormone levels would serve to chemically protect a (theoretical) pregnancy. Really, from a bird’s-eye view, it’s one of the coolest abilities of women’s bodies!
There’s some debate as to whether female athletic training schedules should be actively adjusted to account for these metabolic shifts, versus whether it’s simply one more factor to be aware of when analyzing performance. Personally, while I’m not an exercise physiologist, my firsthand $0.02 is that the effect is probably more likely to be secondary than primary. It isn’t that we suddenly ‘aren’t strong enough’ to lift a given weight or sprint a given pace in the second half of our cycle; our raw physical abilities don’t change that quickly (very recent science confirms this). Rather, it’s that our capacity to execute a given task is chemically influenced — both due to the aforementioned metabolic changes and their ripple effects (for example, a lot of us suffer from disrupted sleep in cycle weeks three and four, which impacts our recoverability). Another crucial piece of this is that our mental game is also significantly impacted by hormones (scientifically: lower estrogen leads to lower serotonin) — and we ALL know how very much THAT matters.
I’d also argue, though, that on some level, this variability makes us lucky. After all, part of what we train for as athletes is the ability to perform under a wide range of conditions. We don’t get to adjust the circumstances to our personal preference. My usual (only half-joking!) explanation for the “man flu” phenomenon is that male hormones stay comparatively ‘flat’ — it’s not that they don’t ‘have’ a cycle, just that there aren’t huge day-to-day shifts the way there are for women — so when men are sick or injured, the comparative difference is often more obvious to them in terms of how their body feels. By contrast, women are accustomed to a much wider range of ‘normal’ — some days we feel amazing, other days we don’t — which can lend itself to an increased ability to ‘power through’ when needed.
As with most things, “your mileage may vary.” Some women will notice huge hormonal influences on how they behave and perform at different points in their cycle; others (my mother, for one) will swear they’ve never noticed any major impact. I am obviously an ‘n’ of one, and can only speak for myself; however, there are certain phenomena that are going to be common among many women, if not MOST. I’m a huge fan of Gabrielle Lichterman’s detailed explanation, as well as Stacy Sims’ book Roar, and my aim here isn’t to duplicate their efforts, but just to (VERY briefly) summarize what’s actually going on hormonally from week to week as a context for sharing my own observations.
Week One: the period. Estrogen and progesterone are at their lowest, which means they’re causing a minimum of interference, and our (comparatively small) amount of testosterone can dominate a little more. This also means that, contrary to popular belief, this week has the potential to be a great time of month for athletic performance. The perception that we can’t perform well while on our period is largely driven by potential secondary factors (namely cramps, anemia, and prostaglandin-induced digestive issues), rather than by the hormones themselves.
Key takeaway: iron. As a medical provider, I’m slightly embarrassed to admit that I did not understand the pathophysiology behind athletic anemia until recently. We know that strenuous training leads to higher cortisol levels (side note: this is why it’s so important to optimize recovery in other areas of life — because your body doesn’t know the difference between cortisol from short sleep, cortisol from a calorie deficit, or cortisol from a horrible workday). Turns out, higher cortisol then leads to higher levels of hepcidin, which is a liver-derived hormone that inhibits iron absorption. (The specific details aren’t necessarily crucial, but it’s useful to understand that there’s some additional pathology at play for athletes beyond the ‘usual’ factors of good nutrition and menstrual blood loss.)
Personally, I eat plenty of meat, nuts, and spinach, and am fortunate to have always had pretty easy periods, so I never considered that I could be iron deficient — but starting back on a women’s multivitamin (with 18mg of iron) absolutely made a difference. I used to feel weirdly ‘floppy’ in the gym during the first couple days of my period — not overt ‘fatigue’ so much as just an extra degree of struggle to stay tight while moving heavy weight — and that doesn’t happen anymore. I haven’t had my iron levels checked recently, which is why I didn’t go straight to a full-dose (65mg) supplement, but I’ll definitely consider upgrading once I get a set of labs.
Week Two: a.k.a. “Superwoman Week.” Estrogen — the more ‘energizing’ of the two hormones — is rising, but we haven’t ovulated yet, so there’s no progesterone to counter it. For most of us, this is our favorite week, whether we consciously realize it or not: it’s a time when we tend to feel sassy, social, optimistic, and physically strong. It’s usually our leanest week in terms of body composition, and from an athletic perspective, we’re often better-coordinated during this week, feel more quickly recovered after hard efforts, and usually feel highly motivated to train. Ironically, it’s also a time when we can be prone to insufficient nutrition, because estrogen has a slight appetite-suppressing effect; food doesn’t feel as ‘important’ as all the other exciting things we’re doing, so it becomes easier to ‘ignore’ the fact that we’re hungry, and we tend to gravitate toward less calorie-dense options when we do eat.
Key takeaway: this is often a good week to go for a PR. Regardless of what exactly drives the phenomenon (whether the factors at play are primarily physical vs mental), the reality is that we tend to be able to execute better during this week, especially with regard to maximum lifts and power-based efforts.
My experience is that I often feel like a greyhound during this week — happy, but also unusually restless, wanting to ‘keep moving’. I drive faster; I take extra walks; I choose more aggressive music. (I’m also more talkative — I had a phone interview with Gabrielle Lichterman on day 10 of a recent cycle, and she wasn’t even trying to hide her laughter at the fact that she was able to immediately peg my hormone phase!)
Week Three: …is a roller coaster. Progesterone, which hasn’t played much of a role until now, starts to rise; it’s a ‘slowing’ hormone that makes us feel more quiet and tired. Worse, though, is the fact that estrogen also suddenly plunges (following ovulation). Low estrogen is closely linked to depression and negativity (because of its effects on serotonin), and, timeline-wise, this drop is also the most abrupt change of the whole cycle — which feels all the more catastrophic because of how UNSTOPPABLE we felt just a couple of days prior!
The best explanation I’ve heard for this phase is that it’s the week when “your body assumes that you could be pregnant” — because you ovulated, and so, from an evolutionary standpoint, the smart thing for it to do is to briefly “assume” that there COULD be a fetus to protect. All the things that happen during this week — increased appetite, slower digestive system, increased fatigue, water retention, metabolic shift toward increased fat-burning — are intended to nourish an early pregnancy. (Our bodies don’t get the memo until the start of week 4.)
Key takeaways: SLEEP and FOOD. Meaning: we need lots of both. We’ve established that, scientifically, the physical impact on athletic capacity is minimal enough that it’s probably not worth proactively adjusting training around cycle — however, on a secondary level, plunging estrogen means we often don’t sleep well during week 3 — and poor sleep impacts literally EVERYTHING (recovery, mood, appetite). This is amplified by the fact that progesterone makes us more sensitive to drops in blood sugar (read: ‘hangry’!) and that our basal metabolic rate increases slightly during this cycle phase (most estimates say we probably need 100-200 more calories per day than we did in weeks 1-2). In other words, much of the impact on athletic performance during the luteal phase may be driven less by a true physical limitation and more by the unfortunate combination of poor sleep + increased hunger + plunging estrogen making our brains work more negatively.
Personally, this tends to be the absolute worst week for me. I know exactly when week 3 starts, because in terms of my mental outlook, it’s like a switch has flipped. There’s always one training day in week 3 where I feel ridiculously frustrated for the whole session, as though I’m failing at absolutely everything… and then I look back at my (perfectly fine) performance a few hours later and think to myself, “Okay, so what exactly was so wrong with that again?”
However, it’s worth mentioning that (depending on the sport) this can actually be a really good week for some female athletes; being a little more inclined towards fat-burning means steady-state work can feel significantly easier. For me, while heavy barbells often don’t feel great, some of my best running and rowing efforts tend to happen in week 3. (But for prolonged endurance work, such as that of marathoners or triathletes, we’re significantly more prone to heat injury and electrolyte disturbances during this cycle phase — Roar contains a lot of superb information about the fueling and hydration strategies that will best counter this.)
Week Four: is something of a relief — our bodies finally figure out that we are not in fact pregnant. Contrary to cultural expectation, this week actually has the potential to feel a lot better than week 3 — first because both female hormones are trending down (causing progressively less interference), and also because the changes are more gradual (compared to the peaks and valleys of week 3). It can still feel like purgatory in terms of day-to-day activities, especially for the first half of the week — falling estrogen leads to irritability; falling progesterone messes with sleep — however, as athletes, clearing those hormones out often actually feels good in terms of our physical performance. For me personally, there’s always a day that I’ve nicknamed “GPS” (the “Great Positive Shift”) — about 48-72 hours before I start my period, my mood pops back up to normal and training suddenly feels good again. I look forward to that day every month.
Another of the tips I read in Roar is that, because BCAAs cross the blood-brain barrier, taking them before exercise can theoretically help decrease the impact of cortisol on the central nervous system (which is heightened in cycle weeks 3 and 4). It could be a complete placebo effect, but my preliminary experience is that it did actually seem to help me the couple of times that I tried it.
Key takeaway: SLEEP. (Yeah, same as in week 3.) The fact that BOTH female hormones are now trending down means a double whammy in terms of the potential impact. Personally, I’ve had good luck with ZMAs (or just plain magnesium), and I’ll add 5mg melatonin if I’ve had a couple of rough nights in a row. Another thing I’ve worked out by trial and error (thanks, NYC Marathon…) is that if my cortisol is staying high enough to wake me up at 2:00am, I’m usually HUNGRY, whether I realize it or not; my best luck with getting back to sleep quickly usually involves a glass of milk or a few swallows of a protein shake.
In summary — this post is intended to serve as a source of both information and validation. These chemical shifts are real; just because we can’t ‘see them’ doesn’t mean they don’t exist — and I’ve talked to enough other women about this in recent months to realize that if it’s taken me until my mid-thirties to start to get a handle on it, there are definitely lots of others out there who are still actively working on piecing together their own learning curve. Every woman is different (heck, every MONTH can be different!), but the bottom line here is just that knowledge is power. Tuning into your body’s patterns can’t do any harm. If the only thing we gain from this is that we find it easier to forgive ourselves when we have a bad training day in week 3 — well, that’s a pretty valuable benefit right there, isn’t it?
A menstrual cycle isn’t an ‘excuse’. It’s a stimulus to keep learning about ourselves, as women and as athletes. The state of our hormones on a given day is just one more impetus to learn how to adapt and work within fluctuating circumstances. (‘Functional fitness’, if you will!) We already do this with plenty of other physical realities — ‘uncontrollable’ ones like injury or pregnancy or weather conditions, but also VOLUNTARY ones: the choice to use a heavier kettlebell or a thicker pair of rings or to lift from a deficit instead of from the floor. We’re broadening our self-awareness — and, therefore, our capacity — every time we push the limits of what’s ‘comfortable’. Our hormonal cycle is a challenge of a slightly different nature, true — but that doesn’t mean we aren’t made better — and stronger — for it.