As women, we are no strangers to menstrual cycles, reproductive systems and all that goes with it. Yet, so many women who exercise have questions about our chance of conceiving, fertility treatments, and what physical activity — particularly running — is okay before conceiving and during pregnancy. I asked those tough questions and got some truthful, real answers straight from a doctor who specializes in obstetrics and gynecology. Today I’m sharing what I learned about how exercise and running affects (or doesn’t affect) fertility levels in women.
I spoke with Dr. Jeff Williams, an OB-GYN who specializes in infertility with Novant Health. He is originally from Knoxville, TN and completed his residency in Missouri and his fellowship in Nebraska. He just moved to Winston-Salem, North Carolina in September and I sat down with him to ask him how working out and running can affect fertility.
There is a LOT of information in this post and it can be pretty dense to digest it all. So I hope you really take time to read it. Understand it and then speak to your doctor about your specific situation!
Effects of general workout exercise on a woman’s cycle and fertility
Do different types of cardio impact fertility more than others? (e.g. running vs. spin class) And does running impact fertility more than other types of workouts (e.g. yoga, barre, lifting)?
Dr. Williams explained that “The intensity and duration of exercise is probably more important than the specific type of exercise. For example, running, cycling or gymnastics in particular have not been proven to impact fertility. But doing any one of these with high intensity could have an impact on fertility in specific situations. No one exercise is worse than the other in affecting a woman’s ability to conceive. In general, it’s safe to say that moderate exercise before, during and after conception has many health benefits.”
The American College of Obstetricians and Gynecologists states that “Physical activity in pregnancy has minimal risks and has been shown to benefit most women, although some modification to exercise routines may be necessary because of normal anatomic and physiologic changes and fetal requirements.”
Should I avoid long runs or intense workouts during ovulation if I’m trying to conceive? How much exercise is too much when trying to get pregnant?
Dr. Williams: “Regarding exercise before, during and after ovulation, specific exercises likely won’t be more or less detrimental depending on when they’re done or avoided during the cycle in a woman of normal fertility. If you are somebody who has a healthy weight, a Body Mass Index (BMI) of 18.5 to 25, and you are used to running a specific amount, you could continue to run and do what you normally do.”
But, if you don’t exercise intensely or consistently and you want to exercise to stay healthy (and you have a normal BMI), Dr. Williams said that aiming for about 150 minutes per week of moderate intensity would be healthy for most patients. (Moderate intensity is something like brisk walking.)
If, however, you are having difficulty conceiving, you need to speak with your physician who may recommend you reduce your exercise intensity or duration even if you have a normal BMI.
Can body fat measurements affect fertility? What if I lose weight?
It’s accepted throughout the medical field that a healthy weight is a BMI of between 18.5 and 25. BMIs greater than 27 and less than 17 are associated with increased ovulatory problems and can affect a women’s fertility. (Source)
One study showed that women with low or underweight BMI of less than 18.5 have a 25% increase in the time needed to achieve conception. “If women lose too much weight as a result of their workouts, it can be detrimental to fertility,” Dr. Williams shared. He also mentioned that some studies show that “high-intensity workouts may be associated with a reduction in fertility in women who already have a normal BMI of less than 25.”
Studies suggest that this happens because of the intensity levels of the workout rather than any specific exercise itself. In contrast, women who practice high impact, high-intensity workouts and have BMIs higher than 25 are less likely to have infertility as a result of their exercise alone.
So, it’s not necessarily running that will cause infertility but that high intensity running in the context of a BMI of less than 25 that may impact it.
Another study compared women with a mean BMI of 19.2. They found that if those women gained around eight pounds, this weight gain would contribute to fertility. Remember that BMI doesn’t take into account your body fat. So it’s important to have healthy body fat levels and stay at a healthy weight for your height. Those will both have a beneficial effect on fertility.
Bottom line on body fat and BMI:
Having open conversations with your doctor about your weight (including weight loss or weight gain), body fat, BMI, activity level and family goals is critical since there are so many factors that a simple calculator from the internet won’t give a full picture of your specific situation.
Effects of Running On Fertility
How will I know if distance running is impacting my fertility?
Dr. Williams: “In many cases, there are not always obvious signs or symptoms that indicate running impacts fertility. Sometimes the first sign is an abnormality in a woman’s cycle. This includes longer cycles or the disappearance of a cycle entirely. It’s important to have an annual exam with your OBGYN. Bring up this question so he or she can address your specific situation since there are so many variables.”
Dr. Williams shared that if you are a woman with a BMI within the normal range of 18.5-25 and you are already a consistent runner, you likely could continue to run as normal and it won’t impact your fertility. But, if you are having difficulty conceiving and you are already of a normal BMI, your doctor may ask you to reduce the intensity of your exercises; furthermore, starting a high-intensity exercise program may not be a good exercise plan for you to move forward with.
If you are not used to vigorous running or high-intensity exercise, opt for 150 minutes per week of moderate-intensity workouts after speaking with your doctor. This would be equivalent to brisk walking or yoga; both are shown to be healthy for patients.
Does the pill or other types of birth control impact training/running?
Dr. Williams: “Some patients choose to use birth control because they have fewer bleeding days. This in turn, makes exercise or running more convenient for some women. The benefits of exercise, in general, has been shown to help reduce painful menstrual cramps in some women. It won’t necessarily make you faster or slower.”
I don’t have a regular period with my IUD. How will I know if I’m missing my period from running too much?
Unfortunately, contraceptives containing hormones (including pills, implants, IUDs) can affect a woman’s menstrual cycle leading to the inability to use cycles as an effective energy marker. This is why annual screenings are so important, especially for active women or those who consistently do intense workouts.
Dr. Williams suggested talking to your OB-GYN about your specific type of birth control and activity level since you may not have an easy-to-track cycle. And keeping track of your cycle’s regularity is one of the keys to knowing if there are any issues.
Measuring your hormonal levels
Are there tests you can do at home to test hormone levels?
While there are several hormonal imbalance tests you can buy online, Dr. Williams recommends against using them. Why? “Female hormonal fluctuations are normal throughout a woman’s menstrual cycle and specific hormones are targeted at different times throughout your cycle. If you are not collecting these hormone tests at the right time in your cycle, it is very difficult and often impossible to interpret what your results mean. That is why hormonal evaluations should be ordered — and interpreted — by a licensed physician.”
The Female Athlete Triad
Highly active women are at risk of having what’s called the “Female Athlete Triad”. Or at the very least, symptoms of it. Every OBGYN should be looking for this with active patients. Dr. Williams reminded me that “As a patient, it’s imperative that you share specific details with your doctor about your activity levels, energy levels and caloric intake.”
The Female Athlete Triad is made up of three components:
- Menstrual dysfunction
- Low energy availability (with or without disordered eating)
- Low bone density.
Dr Williams stated that, “Typically, for most cases, the menstrual cycle is the first to go, or disappear. When this happens, patients should seek out expert advice through their OB-GYN. Now, missing a period in and of itself is not really the problem. OB-GYNs are concerned with why you are losing your period. This can vary from patient to patient.”
“Having and keeping track of your normal menstrual cycle can be used as a marker of appropriate energy levels within your body. Once a woman’s energy balance is restored and energy is no longer being pulled from the reproductive system, it is likely that a regular period cycle will commence – but this will vary from woman to woman.”
If you are an intense exerciser and you skip your period when you typically have a regular cycle (and you’re not pregnant!), “After first speaking with your doctor, sometimes a good first step is to back off your training and/or increase your nutrition to see if it comes back. But again, in general, it’s always good to make an appointment with your OBGYN if you miss your period.”
However, if an OBGYN suspects a patient has the triad, they should ask appropriate questions to confirm their suspicions. If confirmed, you essentially don’t have a healthy energy balance, either through insufficient caloric intake or through excessive, intense exercise.
Your body has responded to the excessive exercise by sacrificing the reproductive system by trying to hold onto energy for other more vital parts of the body.
Dr. Williams explained, “Insufficient calories or excessive exercise causes a woman’s body to have low energy levels. In response to low energy levels, the body starts to pull nutrients from the bone which leads to low bone density. Low bone density is known to cause fractures in the short term, and can even affect bone health into the future. Your doctor may want to do a bone density scan, depending on what symptoms you’re presenting and how severe they are.”
Dr. Williams emphasized that if you are concerned that you suffer from an eating disorder, know that you excessively restrict your food intake. Or have suffered from a stress fracture, talk to your doctor sooner rather than later. “These behaviors might be strong indications that you have an energy imbalance in your body which can affect your ability to conceive. Other problems that can occur in the female athlete triad include painful intercourse, elevated cholesterol, and cardiac health issues.”
Long distance running and fertility: How much running is too much exercise?
What does “excessive exercise” or “vigorous exercise” mean? What about ultramarathoners who are able to maintain a period because they fuel their bodies appropriately? People love pinning things on “excessive exercise” but do you agree that the nutrition portion of it is equally important? If women appropriately fuel, can they safely train for very long distances?
Dr. Williams said that, “It’s often not a problem until it becomes a problem”. He agreed that there are many women who run 100+ miles a week and don’t have issues. For many women, they can just continue what they’re doing and conceive easily. “But, if you’ve been trying to conceive for 12 months and everything else in your evaluations is normal (thyroid, prolactin, hormones, tubes are good, male’s sperm is fine, etc.), then we may need to consider that it’s something else. You may need to increase your caloric intake to give the body more energy to support the reproductive system. Take some stress off the body.”
Fertility Tips for Runners
Finding a doctor who helps you feel supported in your exercise goals is key. Find one who is supportive of your running and will help you explore other explanations for fertility issues rather than immediately shutting down your workouts.
And remember, it’s important to share just how much you’re exercising. For example, I’ve always told my OBGYN that I run 5-6 days a week but I didn’t share that I run 40-60 miles a week. (I will going forward!) That level of mileage is very high compared to the general population. So, it’s important to call out circumstances that make your health situation unique.
Diet and Supplements
Do certain supplements or diets help fertility?
A diet that is high in antioxidants could be beneficial to help preserve fertility or help when you’re trying to conceive. But, Dr. Williams shared that there isn’t any known data that supports a specific diet. But a balanced diet that’s high in antioxidants may be beneficial for fertility.
As far as specific supplements for women who are trying to conceive, you should speak to your physician.
“One in particular that I use often for women with polycystic ovarian syndrome is something called Myoinositol. Myoinositol is a supplement that’s been shown to potentially improve ovulatory events and improve egg quality. Interestingly, an embryologist can actually look at an egg in a women that has had supplementation with Myoinositol and they will see beneficial anatomical improvements in the egg. So we think it improves egg quality and benefits the ovulation event,” Dr. Williams said.
But, don’t just go buy that on the internet without speaking to your doctor. “It’s always best to speak with your physician before making any major changes and taking supplements.”
Be your own advocate
The biggest thing I took away my conversation with Dr. Williams was each and every person and fertility situation is different with so many variables and I really need to speak up with my specific questions. Don’t only rely on your doctor to bring up a specific issue since they see so many patients with so many issues. And again, if you don’t give your doctor all the information in specific detail (e.g. activity level, nutrition concerns, etc.), they may not know to explore something further.
It’s so incredibly important to talk to your doctor and discuss your health to find the root issue if you are struggling with fertility. And even if you aren’t struggling with fertility but want to make sure you’re taking care of your health to prevent issues down the road, Dr. Williams suggested going into every doctor appointment (including your OBGYN). Include goals or a list of questions that you’d like to discuss.
It’s your appointment so be an advocate for your own health!
Dr. Williams shared, “It’s helpful if a patient comes in saying, ‘This is my chief complaint or this is what I want to talk about today.’ Go into your appointment with your specific concerns and that will help your doctor get to any root issues.”
I hope this post helps you with your running goals and health, both short-term and long-term. I know I found the conversation incredibly valuable. A big thank you to Dr. Williams and the Novant Health team who spent so much time to help address this important topic on the effects of running on fertility.
Happy, healthy running!
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This post was sponsored by Novant Health. A big thank you to them for not only supporting my blog, but also supporting me and my readers in reaching our running goals and living long, healthy lives
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