The Period Posts: How Your Menstrual Cycle Affects Your Running Performance

See you tomorrow, male readers.
See you tomorrow, male readers.

Last week, in our Period Post, we told you all about the hormonal craziness that happens during your menstrual cycle. Today I’m going to tell you how all this hormonal craziness affects your running.

A quick disclaimer before I get out my hormones and test tubes again, though:  I am not a doctor.  I am not a scientist.  I do not have all of the answers, and none of mine should ever replace those of your own physician or OB/GYN.  I double-majored in English and Biology in college, but only completed a degree in English. I’ve learned a ton about the inner workings of the lady-parts through my infertility journey, albeit mostly related to my specific problems.

Nonetheless I am providing you with sound, researched science; some from my past studies, some from textbooks, and some from sources I will cite at the end of today’s post.  And finally, I am keeping some really complicated science as simple as I can in the interest of keeping these pieces approachable and useful.

Now, if you thought last week’s installment in our month-long “Salty Confidential” series was challenging, just wait until you see what we have in store next.  Today, we’re tackling how the menstrual cycle (hormones) impacts your metabolism, and therefore, your running performance.  Here’s a hint:  it does.

An even bigger surprise?  I’m yanking the cloak off the evil period.  The period is the bad guy (girl?) no more – and we’re about to tell you why.

The Follicular Phase:  Revisited

Ever have one of those killer runs two or three days into your period?  One of those runs that’s so awesome you kind of forget you have it?  I’m not talking day one, when you’re still crampy and moody and bloated, but a couple of days in, when the worst of it is over.  You know, that run?

Well, you’re not alone.  And there’s a reason for it.  Science.

Watch out! Clove’s wearing her scientist (trucker) hat.

To recap last week, the follicular phase actually starts with your first day of bleeding, or “Day 1” of your cycle.  You’re probably not going to feel great that day, and why should you?  You’ve got cramps and residual bloating, and let’s face it, the whole thing is really a bit of a pain.  Scientifically, though, you’re on the upswing.  Your levels of both estrogen and progesterone are close to rock bottom, after that whole performance late in the luteal cycle where progesterone suffocated estrogen, bullied the corpus luteum to jump off a cliff, and didn’t realize it had basically designed its own end.  Essentially, the hormonal drama is over for a couple of weeks – and the period itself is your body’s way of cleaning up the mess.

Those crappy runs the first couple days of your period?  Kind of like a hormonal hangover.  The hormones are low, but you’re still feeling like crap from being put through the PMS ringer and your poor little uterus is being wrung out like a washcloth.  Metabolically speaking, though – your body is primed to run.

Being metabolically primed to run is what brings me back to that first run I was talking about – the killer run two or three days in.  Why does this happen?  What kind of cray-cray is your body up to anyway?  Here goes:

During the follicular phase, FSH and estradiol (those estrogen hormones) are working on your ovaries to develop a number of follicles that will (eventually) get whittled down to one.  Throughout that follicular phase, which lasts an average of 10 to 21 days depending on the woman, those estrogens are in control – and rising.  These are the happy days.  You feel good, light and fast.  You run well – whatever well is for you.  In general, the follicular phase, or the first two weeks of your menstrual cycle, are the best training time you’ll get all month.

Why?  Estrogen, baby.

Research has shown time and again that estrogen causes better, faster and more efficient metabolism of carbohydrates, fats and proteins – making more energy available faster.  This is further augmented by the fact that estrogen (the wonder hormone) also increases the availability and synthesis of glycogen in the muscles.  Glycogen!!!  That’s our bread and butter, ladies!

So throughout that follicular phase, that estrogen is going up … uP … UP … and it’s quite possible, if you started tracking your cycle alongside your workouts, that you’d see some terrific performances.  Until …

Dunh dunh dunh.


Don’t worry, ladies, it’s not game over yet.  But it does start to get dicier now.  You’ll recall that ovulation is preceded by a surge of LH hormone – which is the result of an estrogen threshold mechanism.  Ever heard the phrase “too much of a good thing?”  As a fertility patient, I’m here to back it up:  too much estrogen is not a good thing at all.  It makes you tired.  It robs energy and motivation.  It makes you … HUNGRY.  And it peaks at ovulation.

Keep that training log – see if you don’t have a couple tougher runs right around ovulation.  Not only is that estrogen peaking to the threshold point (think Bruce Banner/the Incredible Hulk), but your body’s doing something kind of big, here.

Think ovulation isn’t all that interesting?  Well, it is only a 36 to 48 hour process.  But if the follicular phase represents all your badass running dreams come to light, hold on tight.  The luteal phase is here, to once again, RUIN EVERYTHING.

Luteal Phase

If you have ever even jokingly thought that women have the periods and babies because men can’t, I present to you the metabolic disaster area that is the luteal phase.  It would bring any man but Sheldon Cooper to his knees.  And maybe even him.

Public enemy number one. This, along with panty hose, was surely invented by a man.
Public enemy number one, progesterone. This, along with pantyhose, was surely invented by a man.

AWESOME ESTROGEN NO MORE:  All that awesome estrogen?  Not only is evil (evil!) progesterone hormonally suffocating it, but it also acts as an antagonist to it metabolically.  All that yummy glycogen coursing though your veins?  Going … going … gone.  By the time progesterone peaks between 7 and 10 days after ovulation, your body has transitioned to burning fat as its primary fuel source in order to preserve glycogen.  Even better?  Low glycogen can equal low blood sugar.  You know what low blood sugar can equal?  A lowered lactate threshold, especially in your faster workouts.  What?  You did those Yasso’s two seconds faster last week after staying late at work and eating garbage all day?  Yep.  You probably did.  Thanks, progesterone.

ROCK STAR RUNS FOR THE TRAINING LOG?  Not so much.  Wonder why you had a great run a few days ago, took a day off to recover, and now feel like trash?  I’ve paraphased Jason Karp, PhD, an exercise physiologist, 2011 IDEA Personal Trainer of the Year and co-author of Human Kinetics “Running for Women” to explain:

Progesterone (evil!) stimulates a higher heart rate, resting pulse and breathing rate independent of the intensity of your run, which can increase your perception of how hard that run is.  Breathing levels are greater during the luteal phase, when progesterone concentration is highest, which can lead to women feeling more winded than they did in the same workouts just weeks before.  And if you’re using more oxygen just to breathe – there’s less going where you really need it [your legs].

Thanks, progesterone.

I hear progesterone is also responsible for every starting area porta-potty being out of toilet paper. Figures.
I hear progesterone is also responsible for every starting area porta-potty being out of toilet paper. Figures.

IT’S GETTING HOT IN HERE:  Women who have tracked their cycles for any number of reasons know that along with ovulation comes a temperature change.  We’re not talking fevers here; in fact, we’re talking such small variations that you need a special thermometer, a basal thermometer, to even pick up on them.  But as soon as you pop that egg and get progesterone in the house, you see a little rise in your basal body temperature.   And then your basal temperature stays up – or may even go a smidge higher – until the day you get your period, when it drops back down.  The long-term problem?  I quote Dr. Karp once more:

“A higher body temperature during the luteal phase makes it harder to run in the heat, because you don’t begin sweating to dissipate heat until you have reached a higher body temperature.  Women also have a decreased ability to dilate the small blood vessels under the skin, which compromises their ability to release heat to the environment.”

Just another reason to take the Salty Challenge and get that shirt off.  Oh, and thanks, progesterone.

TIPPING THE SCALES?  You’re not alone – and it’s not just bloating.  Follow me here.  Progesterone (saboteur!) is antagonizing our estrogen.  Estrogen is what helps us burn through all those carbs and sugars lickety-split like the badass runners we are; progesterone is causing us to conserve the carbs/sugar/glycogen and burn fat instead.

Okay, Clove, you’re saying.  Don’t we want to burn fat?

Well, not this way.  Because what does your body store all those excess carbs and sugars that aren’t getting burned off as?

You got it.  Fat.

And when is your weight the highest?

You got it.  End of the luteal phase.  Not uncommon at all for a healthy woman to drop one to three pounds in the first three days of a new menstrual cycle.  You know, as soon as that progesterone’s gone.

So no, Salties, you are not just cranky, crampy and bloated.  And you are most definitely not imagining things.  You are, quite literally, a hot mess.  A bloated, metabolically altered, mildly hypoglycemic, out-of-breath hot mess.

Say it with me.

Thanks, progesterone.

Some scientists believe progesterone works a little differently than what this dude says.
In the interest of equality, I should mention one alternative theory about how progesterone works to negatively impact your performance.


Which brings us, finally, back to Day 1 and the period.  Is it any wonder I don’t see the period as the bad guy in this process?

In the final one to two days of the luteal phase, your progesterone (finally) takes a nosedive, dropping from that peak level of between 8 and 15 ng/ml  down to <2 ng/ml.  Once it hits your body’s personal threshold below that <2 ng/ml mark, it’s a whole new day.  If you’re not trying to get pregnant, your period is not only a sign that your body is functioning properly – but that all that progesterone garbage is OUT of your body.  Those light and airy carefree runs are on their way back, and as soon as you get rid of those cramps, you’ve got a two-week reprieve from that little saboteur named “progesterone.”

It almost makes me understand that grating slogan for Always maxi ‘;[pads.  So yeah – get out there, girl.  And have a happy period.

So what do I do with all this?

You know, ladies, in a way that’s up to you, but I would suggest three things:

  1. Track your cycle alongside your workouts for three months, and see what personal correlations you find.  We are all still an experiment of one, and your findings may be different from mine.
  2. Be aware of the fluctuations in your cycle, plan for them, and assess your fitness and your “bad runs” with a close eye to the special challenges you face as a woman.
  3. Read the articles referenced here: and, and talk with your own OB/GYN to discuss the best ways for YOU to maximize your training throughout your menstrual cycle.

What about the cray-cray?

  1. Well yes, it’s true.  The optimal time for you to race is actually towards the end of your period.  Crazy, right?
  2. Yeah, seriously.  Women can have different lactate thresholds at different times of the month.  Weird science, I tell you.  Weird.
  3. Can’t figure out how “that girl” ran circles around you at that 10K?  No worries.  She’s just hopped up on estrogen.  You know there’s a reason that male bodybuilders take this stuff, right?

And last but not least, I leave you with two teasers for our upcoming posts.  Next week, Salty Confidential will bring you our most candid roundtable ever – period – when the Salties open up about their own cycles and challenges to help demystify the day-to-day (or month-to-month) issues around running with your period.  And for our final installment, we’ll find out the facts about hormonal birth control and running.  Does it make you slow?  Does it make you fat?  Is it bad for your running?

I’m going to go out on a limb here and guess that the progesterone-based and progesterone only pills aren’t such a good idea.  Hint, hint.

How do you feel like your cycle affects your performance, if at all. Do some of those bummer workouts and races make more sense after reading this post?


Related Posts

Salty Confidential: The Period Post

Trail and adventure enthusiast. Girl who swears like a sailor but not when she's teaching Sunday School. Survived infertility without a successful pregnancy. Self-employed, primarily working for Clif Bar and Company. Thirteen 100-mile race finishes with seven top 3 placements. An original Saltine.

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  1. This is intriguing to me. Thank you for doing this research and sharing this with us. It definitely makes sense and it makes me want to pay more attention to my own cycles and training.

  2. Ok. So I was intrigued and went back to my training log. Here is for 5 days before my period in July 2011:

    “This one got me so frustrated I cried. I was just so dead tonight and got smoked. I had to WORK to meet the times for the first set. Even the 200’s which I usually love were labored. By the second 600 I felt awful. I made it 200 and was already way behind everyone. I felt weak, no power, nauseous, hot, miserable, I did the walk of shame through soccer practice and freakin’ cried. I wanted to get in 10 tonight, but bagged it early given how yucky I felt. I thought I had a better mental grip on everything, but my emotions got the best of me tonight. But, I am moving on. Tomorrow is a new day”

    Damn progesterone 🙂

  3. I’ve looked too. My worst feeling 100-miler ever? The one three days before I got my period. Not my worst TIME, but the only one that I had no snap, no energy, no motivation.

    My best? I mean seriously, the one where I felt superhuman all day and ran my still standing PR?

    The one I finished two hours before starting my period. That’s right, I basically got back to my hotel, went to the bathroom, and there it was. I had been terrified it would start during the race – especially since I was technically finishing the day it was due. But the cramps hadn’t started yet, the progesterone was gone, and I was in some freakish zone that I dream of returning to. I’m telling you, CRAZY.

    1. I’ve run 3 marathons during my luteal phase – ew. They were all plagued by stomach issues and in a couple of them I was stitchy and all of them I felt heavy and like I was forcing it. My first was the one that went the best and it was about 8-10 days after my period. The last one was the third day of my period and I bonked. I’ve wondered if there was some weird metabolism stuff going on because I was still nursing? Or perhaps I just bonked. Dudes bonk and they don’t have this stuff going on. Who knows!

  4. Awesome Awesome post!!!!! Knowing that hormonal fluctuations could be the explanation for why some of those runs just feel like crapola helps SO much!!! I can quit beating myself up and blame the Evil P!! 🙂

  5. Awesome post! Anecdotally, I figured out that period = happy running by tracking things through several years of our own fertility frustrations. My friends thought I was NUTS when I figured out that I was going to have my period for a huge goal race AND WAS PUMPED ABOUT IT. Always good to know there’s data backing you up!

    There’s something to be said, though, for those end-of-the-month, progesterone-laden efforts, both in training and in racing. Guaranteed (forced) monthly mental toughness training! Since the secret’s out, it might be tempting to fudge the schedule or forgive some slacking. Who wants to head out for a long run knowing that her running shoes are going to feel like lead boots every step for the next 3 hours? Or go into a track workout knowing that the intervals that just about did her in last week are actually going to be finishing the job this week…and be slower?

    The scientist in me wonders if the changes in metabolism lead to different gains for different efforts at different times of the month (and then relishes the fact that my expertise lies in a field far more concrete and controllable than this mucky biology stuff!!!).

    But the runner in me knows that there are gains made by mentally pushing through tough runs and races. Period or not, race day doesn’t always looked like I dreamed it would. Weather forecasts, mysterious aches and pains, travel and lodging woes (ever share a Murphy bed with someone who has pre-race nightmares?), nursing a newborn, sick kids, sick me, family emergencies, last minute changes to my favorite course, a group that votes for pre-race sushi (personal, I know, but ewww!): all things I’ve known about heading to one starting line or another, and all things that have made me work to keep my head in the game. I’m glad I had a few hormonally trying training runs in my bag to call on when I needed them.

    Race day on a progesterone high? Please, please, PLEASE not when I’m going for my lifelong goal; otherwise, bring it on! (Especially if the alternative is muttering the words, “I can’t. PMS.”)

    1. I am with you on making sure we don’t cut ourselves too much slack when we know it is the wrong time in training. I actually looked at my next race and it should fall at the worst possible time. But I am NOT going to worry about it and decide it will be a bad race before I even get to the starting line! I am actually going to try not to think about it at all until the race is over! 🙂

  6. I’ve had a long work day, but finally made my way back over here. I’m so HAPPY to see the last two comments, because it’s something I left out of the original post due to space constraints and something I forgot to comment on twice.

    For me, the value in knowing how my cycle impacts my own running is being able to write off the very worst runs – the ones that simply make no sense whatsoever. The ones that blindside me. The ones where my breathing is completely whacked out or my energy is just “wrong.” But there’s no way in hell I’m letting myself coast for 8 – 10 days every month – oh, there’s nothing I can do, it’s my hormones. As a matter of fact, while my 800’s may be a little bit harder or a second or two slower than a prior week, I still go to the track intending to hit the sub-3:10 mark on each of them – and I do.

    This is definitely a double-edged sword. While knowledge IS power, it’s not an excuse. In comparing my natural cycles to my workouts, I have definitely found an “explanation” for some of the bizarre runs – but I have also found that while I may feel “better” the first two weeks, I don’t feel terrible the last two weeks. At all. Again, it’s all about finding out how your body works.

    To Salty’s point, I say exactly. Men crash and burn and have a week of crappy runs too. And it’s not progesterone, it just is. Being aware can help us make small inferences, like “well, I won’t decide I’m overtraining until after my period. If I’m still feeling run down after that, I’ll take a look” or “I’ve been running great workouts but I was just dead at that tune-up race – based on the quality of my recent running, it definitely could have been a hormonal fluctuation.”

    But I agree with Amy and Mint 110% – my goals don’t change, and it’s not an excuse to be soft for a week. I go into every workout expecting to push through – and with the odd exception here or there, that’s exactly what I do.

    Finally, I stopped tracking after I found the correlations. And since then, I really have forgotten about it for the most part. I mean, yeah, I know when my period is coming, but in spite of this series of posts, we women are so much than our periods, you know? So now that I’ve stopped tracking, it’s not until I have a weird run that I think “hmpf. Where am I at in my cycle?” Cause most of us stopped waiting up at night for our periods pretty much as soon as we got the first one 🙂

    1. As I was reading this well-written and researched article, I found myself having many of the same thoughts as Amy. And then to read your response Clove, puts it all in perspective, a nice balance of understanding what is going on in our unique bodies and at the same time trying not to hold the science against the art (the art of pushing through these discomforts).

  7. YES! Such a great conversation. Menstrual cycle sh*t is just another factor that goes into how our runs go on any given day. We could still have awesome runs with Evil P in the house. I have. But I do know that my hormones sometimes hit me hard and if I’m in that hormonal zone I can start my intervals conservatively rather than expect to have an awesome night. As for racing, I will seriously consider moving my period or the race if it’s an A race, especially a marathon, but otherwise, it should be a non-issue. See the fact that it’s just one factor. As Amy says, don’t let it become an excuse to not kick ass!

  8. Both my 70.3 triathlons were a few days BEFORE I started my period… I thought I was lucky! Now I’m less puzzled over my stomach issues and low energy. If the calandar track rights, I should hit my goal 70.3 this year 3 days into the Follicular Phase – which has me oddly excited. 🙂

  9. These posts are fantastic! This one was returned from my desperate, day 1 “I feel really gross, please someone tell me it’s OK to not do my long run” search. I put my big girl pants on, sucked it up, forced myself out the door and, as always, I was so glad I did.

    Why is it always so hard to remember that the feeling of achievement is a million times worth the first few kms of really quite miserable?

    Am now making my own charts to help me be a bit nicer to myself (and avoid dodgy excuses).

    Thanks for the information – have added your blog to my Feedly..

  10. I wish I had thought of reading this before running my first Marathon OR remembering that my period was coming. I just ran the LA Marathon this past Sunday, I thought it was the heat that got to me, but it was a combination of both. What’s the correlation of needed to go to the bathroom more frequently, right before a period? I’m now really grateful that I did finish since this was by far the least ideal day to run and get my best time.

  11. Me too!! I thought that it was completely nuts for me to feel worse just before it rather than during.

    I also find that during the first week following it, I am freakin’ awesome and full of energy. My best races have been during the week immediately following my period.