Running performance and the menstrual cycle

One of the aspects of running that I love the most is understanding how our bodies work.  I have a biomedical engineering background in sports medicine, but I didn’t really start to run until several years after I finished my masters degree.  (Ironically, I simulated the Boston Marathon for my thesis waaaaay before I had ever run a marathon.)

One of the most complex and fascinating areas of science are the hormones that make us tick.  I never gave hormones their due respect until I got pregnant and realized within days that my body had completely changed as a result of a few hormones starting the cascade of signals to grow a baby.

I have been breastfeeding for 20 months now (check out a recent post on extended breastfeeding here), so my hormones are still a bit on the postpartum spectrum, but my period returned at 16 months postpartum and so far I’ve been regular every month.  With this, I’ve taken a new interest in understanding how different levels of hormones during the menstrual cycle affect running performance.

I was on birth control for as long as I can remember before my husband and I decided to have a family. With that, I do not feel like I experienced the same shift in hormones that I feel now that I am BC free.  Before you give a point to BC for eliminating noticeable shifts in how I felt, also note that I think that BC may have negatively affected my performance.  I have come back postpartum way faster than I was pre-pregnancy, and I don’t have as much body fat. (Little sidenote: Steph Rothstein Bruce did not use BC because of her suspicions that it could affect performance, and that is how she unexpectedly got pregnant with blessing #2.)

So back to the hormones:  There are two main phases: the follicular phase (days 1-14), in which you have your period and ovulate, and the luteal phase (days 15-28) when the body is preparing for a possible pregnancy.

Follicular Phase: First menstruation occurs at day 1, and then around day 5 or 6, estrogen starts to increase along with a hormone called the follicle-stimulating hormone (FSH).  Around day 12 the estrogen levels surge with the luteinizing hormone (LH), which causes ovulation and an egg is released.

Luteal Phase: After ovulation, estrogen dips for a brief time, only to rise again with progesterone, as the body prepares the lining of the uterus for possible implantation.  Estrogen and progesterone peak around 5 days before menstruation. If the egg isn’t fertilized and implanted, progesterone levels fall and the body returns to day one with menstrual bleeding.


This Wikipedia and Wikimedia Commons image is from the user Chris 73 and is freely available at // under the creative commons cc-by-sa 3.0 license.

How our hormones affect us: Our carbohydrate metabolism and recovery are more similar to men in the low hormone phase than the high hormone phase. During the high hormone phase, in which we have higher amounts of both estrogen and progesterone.  High estrogen makes us spare glycogen and utilize fat stores instead. This is not a great scenario for high intensity exercise when we need a fast source of fuel.  High progesterone delays the sweat response, turns up core temperature, increases sodium loss, and increases muscle breakdown.  The result in this shift to the high hormone phase can cause fluids to move into the cells, resulting in bloating, as well as a predisposition to central nervous system fatigue. (Yay! Tell me more!) Ok, so here’s more.  During the high hormone phase, your body is more likely to break down muscle but not re-grow more (low anabolism, high catabolism).

There is not a ton of research on the effects of the monthly cycle and performance, but it is recognized that generally, low hormone times are the best for performance, with actual menstruation being noted as one of the best times to compete.  This is of course, highly subjective, as everyone has a different experience with their cycles.  If you are planning to compete during a high hormone phase, be aware that cooling will be more difficult and that proper protein ingestion will help with muscle catabolism.

What Next: If you want to learn more, I highly recommend the book Roar by Stacy Sims. She goes into much greater detail how the system works and ways to mitigate some of the negative effects of our hormone shifts.  While some of the side effects of the hormonal shifts women experience can be frustrating, we need to celebrate the amazing mechanism taking place so that we can stay healthy and grow our families.  As with just about everything in life, the more we understand, the easier it is to navigate the things of life.

Do you notice a change in your running performance at a specific time of the month?

Do you plan your races around your menstrual cycle?


Book Report: First Ladies of Running

I just finished reading Amby Burfoot’s book First Ladies of Running: 22 Inspiring Profiles of the Rebels, Rule Breakers, and Visionaries who changed the Sport Forever.  I didn’t expect for a book to change the way that I view my position as a female runner, but this book made me both proud and honored to be part of the lineage of such remarkable women.

First Ladies of Running chronicles 22 women and the stories that brought them to running in a time when running was a man’s activity.  Some of these ladies joined men’s running clubs (because that was the only option), and trained really hard to be excellent (I was really impressed to read how most of the men welcomed them).  Others seemed to just go out and run sub 3 hour marathons months after just picking up the sport.  Either way, all of these women did more than just run; they helped advance women’s opportunities and promote equality.

I highly recommend this book to any female (or male) runner who appreciates good history.  Below are some of my favorite quotes from the book, although all of the stories deserve special accolades.


Grace Butcher: “I believe we’re all here to discover our life’s purpose, and then once you’ve discovered it, for Heaven’s sake, get on with it. The saddest words I know are, “If only…'”

Julia Chase: “Running puts you in touch with your primal self and your deepest resolve.  You learn how to deal with pain and other obstacles.  You realize that it’s not important to do conventional things.  You can do whatever feels worthwhile to you.”

Doris Brown: “When you don’t get what you want, you can let it drive you up or down. The more heart and soul you put into it, the better your chances.  Besides, the best things always take a while.”

Katherine Switzer: “It worked just the way my dad said it would. I didn’t have many skills, but no one could match me running up and down the field.  So I learned an important lesson: Running isn’t just about running.  It’s about the sense of empowerment you get from going the distance.  That empowerment can help you succeed in so many other activities.”

Katherine Switzer: “That race fulfilled all my dreams.  In fact, I think the Olympic Marathon was in many ways as important as giving women the vote.  Everyone had come to accept what women could do in the social and intellectual realms, but it took the Olympic Marathon to show the entire world how physical and powerful women could be.”

Sara Mae Berman: “I liked the way that running is different for girls than ice skating, where you have to be pretty, or swimming, where no one sees you sweating under the water, or equestrian events that are so very genteel.  Running takes a lot of hard effort and sweat, and you’re wearing clothes that aren’t much more than underwear. I didn’t run to promote myself, but to promote women’s running.”

Joan Ullyot: “Running gave me great health.  I feel so much better when I’m running.  How could anyone not exercise? It gets me outside every day to appreciate Mother Earth and Father Sky. I had grown up thinking I was terrible at sports, but running taught me that I could be an athlete.  I could be successful with my body as well as my mind.  And it made me so happy.”

Jackie Hensen: “The key is consistency and hard work.  You can’t pass the test unless you’ve done all your homework.  Things can go wrong, and things will go wrong.  You can’t control all the variables in your life. That’s why you have to prepare 100%. You’ve got to give it your absolute best.”

Miki Gorman: “Running gave me so much more self-confidence that my daily life became totally different.  I wasn’t timid anymore. I said what I believed in and what I wanted. I was still shy perhaps.  That is my nature. But I didn’t have fears any longer that kept me from speaking up for myself.”

Miki Gorman: “I learned that the looks and size of one’s body are not important, and that anyone can be competitive.  I gained so much confidence from my running.  I finally realized that being small didn’t have to hold me back.”

Marilyn Bevans: “All my life, I believed if you trained hard, you could get better.  You might never be the best, but at least, you could be learning. At Springfield, we trained hard, and I picked up lots of new training methods. When you have a solid work and learning ethic, it always pays off one way or another.”

Marilyn Bevans: “In my life, it also gave me peace, quiet, and thinking time. When there was a lot going on, it got me out into nature and away from the chaos. It makes you tough, too, from battling with the cold, the wind, the rain, the blizzards, the hills, the heat, and all.  You learn that you can get through stuff. It helps you see what else you can achieve in your life.”

Patti Catalano: “I’d like to think that I helped lay the bricks for other women to follow and to run on. I feel like I was a bridge from some of the earlier women to Joan Benoit. The progress we made is so amazing. When I began running, I didn’t know anything about women’s running. I didn’t even know that we weren’t supposed to be able to run distances. I just wanted to burn calories and get skinny legs.”

Grete Waitz: “The last part of the race in Central Park was very difficult. My legs were cramping, and I wanted to stop. But I didn’t know how to get to the finish except by running there, so I just kept going. It was hard, but at least I didn’t get lost.”

Grete Waitz: “I am in good form and I hope to run well on Sunday.” And after: “I knew I was in good condition, and I felt okay today, so I was able to win.”

Joan Benoit: “Faith is the key to everything. You can never let anyone or anything deter you from your best efforts. There are no shortcuts in life, or in the marathon. The marathon is a metaphor for life. You have to run your own race at your own pace.”

Oprah Winfrey: “Life is a lot like a marathon. If you can finish a marathon, you can do anything you want.”

Chris McKenzie: “If I can carry a baby for 9 months, I can run a 10-k.”

 I admit that I did not know who most of these women were before reading this book, but wow! What an inspiration!

Is there anyone who has been pivotal in helping you love the sport of running? After reading this book, there are a lot of names that I might need to add to my list!