walking on the treadmill?

“The countdown has begun,” read an email from the Boston Athletic Association. “Forty days until the 129th Boston Marathon.” It was March 12 and I was lying on my apartment’s couch recovering from an egg retrieval, which happened hours earlier. Undergoing a second round of IVF before running a marathon was not or extreme exercising during IVF and there’s really no good data,” Gracia tells.

Last year was a different story. Even though I usually sign up for a fall race, I took a break at the end of 2024 so I could go through IVF treatment without disrupting training. The week before Thanksgiving, I began IVF stimulation, the fertility procedure that stimulates your ovaries through hormone injections to help with egg maturity.

After egg retrieval, I didn’t expect to go through another cycle. But my partner and I decided we needed to increase our odds of successful implantation—when a fertilized egg attaches to the uterine lining, resulting in pregnancy—by having more embryos.

It was January 2024 when I spoke with my doctor, Tara Budinetz, D.O., a fertility specialist at Shady Grove Fertility in Bethlehem, Pennsylvania, about starting the next cycle. By then, I had already marked off my marathon calendar for the year: Boston and London in April, Sydney in August. The sensible choice was to wait until May to undergo another round of IVF. But an urge inside me wanted to speed up the process.

Maybe it was the knowing; I knew what kind of toll an IVF cycle would have on my body. With five weeks until Boston, I was confident I could bounce back into marathon shape to get ready for race day. (I have run from Hopkinton to Boylston Street every year since 2013, after all.)

I was also getting tired of pausing my plans and goals, of being unsure if something might pop up mid-year, causing me to regret postponing IVF. If I couldn’t make time—or predict the future—why not do the second cycle right away?

IVF medication took up lots of real estate in our refrigerator.

As I did another round of IVF, I wanted to learn if there were any potential risks runners could experience if they went through the procedure mid-marathon training. So I spoke with a team of experts, including my doctor, Budinetz, and a few others. Considering a 2023 report released by the World Health Organization found that one in six people experience infertility at some stage in their lives globally, I wanted to share what I found, including questions regarding exercising during IVF.

As with any medical advice, you should consult your own doctor first before signing up for a race that coincides with IVF treatment. But with National Infertility Awareness Week coinciding with the Boston Marathon, there’s no better time to share the science (or lack thereof) and what the experts say about running and fertility treatments.

According to Clarisa Gracia, M.D., chief of the Division of Reproductive Endocrinology and Infertility at the Perelman School of Medicine at the University of Pennsylvania, there aren’t a lot of studies out there on active women experiencing fertility treatment.

“In fact, I actually did a little literature search to see if there is anything new about marathon running or extreme exercising during IVF and there’s really no good data,” Gracia tells Runner’s World. “Most studies look at exercise and fertility overall, not specifically around the IVF process itself.”

“When I think about my patient population that I see, there aren’t that many people who are extreme exercisers,” she adds. “Historically, people trying to get pregnant probably step down the exercise on their own.” Plus, most people only exercise 30 minutes a day or even need convincing to hit that amount, she adds.

Of course, if you’re training for a race, especially a marathon, you’re very likely exercising more than 30 minutes a day.

My own search populated studies showing either no difference between outcomes in women who exercise and those who don’t or a positive association between exercising before starting IVF treatment and better implantation, pregnancy, and live birth outcomes. (Every study also points out the need for more and stronger research on the topic.) This includes a cohort study involving 273 women published in 2016, a meta-analysis of research published in 2018, London Marathon Results 2020, London Marathon Results.

A more recent study, published in October 2024, also concluded that exercise during IVF stimulation—brisk walks on the treadmill or outside–lowered stress and did not result in ovarian torsion (a potential complication of IVF stim, which we’ll talk more about later).

As I went about my IVF journey, I became increasingly worried about the quality of my eggs. Unlike men, whose sperm are produced in the testes, women are born with all of their eggs, which decline in number as you age. Considering this information, I wondered if years of running had negatively affected my chances of becoming pregnant. As I spiraled about my eggs, the irony of causing harm by doing something “healthy” wasn’t lost on me.

“Unfortunately, fertility issues don’t discriminate,” Budinetz says. “I think it’s more frustrating for people when they are trying everything they can: They’re active, they’re healthy, they’re running, they’re trying to take care of their bodies, they’re trying to eat the right foods. And it’s almost as if you’re studying for the test, but you’re still not getting the A, and that’s really hard. It’s not like you can just take a pill or just say, ‘Okay, if I do this, then it’s going to happen.’ There’s so many other factors.”

While the biggest factor in lowered egg quality is age, Budinetz says, one thing that all the doctors I spoke with agreed on was that running won’t affect your egg quality.

“Intense exercise does not hurt your eggs at all. I do think, whether you’re infertile or not, women have a bad habit of blaming themselves when something goes wrong with pregnancy,” Molly Moravek, M.D., M.P.H., division director of reproductive endocrinology and infertility at Henry Ford Health, Michigan State University tells Runner’s World.

While some outside factors, like chemotherapy and radiation, can affect egg quality, these instances are circumstantial and very rare.

“The thing about women is they’re born with all the eggs they’ll ever have in their life,” Gracia says. “So whatever you do during your life, you have those eggs. Interestingly there are things such as chemotherapy and radiation, really severe toxic exposures that do destroy eggs in the ovaries. But there’s no reason for me to think that running does that. At least there’s no evidence.”

Because coping with infertility and going through IVF treatment can be a trying time, Moravek also stresses that if a runner is concerned about outcomes, use your own barometer of judgment: If something bad happens and you’re going to look back and then blame yourself, then it’s okay to race in a 5K.

“Recently, someone came up to me after a talk I gave and said that their doctor told them to stop running marathons while they were going through IVF,” says Moravek. “I just can’t think of a single reason why that would be. And if anything, it’s probably worse for your mental health if you’re a runner. And worse for your stress levels. So, I would encourage people to keep doing what they’re used to doing. Now, I wouldn’t say try and run your first marathon while you’re going through IVF, but if it’s something that your body is used to and it feels good to your body, then I say do it.”

With that in mind, there are some signs you shouldn’t ignore when running that would signal something is off with your reproductive system—like amenorrhea or the absence of a menstrual period.

“The line that’s crossed between fitness and infertility is when folks develop the Athlete’s Triad,” says Annmarie Vilkins, D.O., director of obstetrics and gynecology at Henry Ford Health, referring to what’s now recognized as RED-S. “Running May Fight the Onset of Brain Rot, menstrual dysfunction, and low bone mineral density are the three components of the triad; not all have to be present for an athlete to have the condition.”

Vilkins will usually recommend seeing a fertility specialist if her patients are under 35 and they’re having trouble conceiving after trying for a year (six months if they’re 35 and over). If you have PCOS or endometriosis, it’s also worth seeing a specialist early on when trying to get pregnant, as these conditions can increase risk of complications.

“[But generally speaking] being active and being healthy is absolutely a good thing in terms of someone’s fertility,” says Vilkins, an avid runner herself.

So comes the big question: Is it okay to go though an IVF cycle in the middle of training for a marathon?

During my first round of IVF, I was tormented that I’d have to start injections at The Running Event, an annual trade show that showcases new running gear. I figured starting treatment would mean I wouldn’t be able to run. I was surprised when Budinetz said I actually could go out for miles at my normal intensity Moravek puts what’s happening during implantation into perspective when it comes to activity.

With her blessing, I was able to do shakeout runs and race in a 5K the second day of IVF stimulation. I continued running, gradually slowing my pace, until day six when I resorted to walking on the treadmill.

“During IVF, there’s about 12 days of stimulation,” Budinetz says. For the first five to six days, your ovaries get bigger, but you can still run and do other activity. But after the first half of the stimulation (after day six), it’s time to tone it down, especially as you get closer to retrieval, she explains.

If you’re feeling fullness and uncomfortable—at any time during the IVF stimulation cycle, but especially after those first six days—that’s your body telling you not to push it, Gracia says.

“Most people say that after about six or seven days of stimulation, that’s when the ovaries start growing,” she explains. “And of course, that’s depending on what things look like, because we start doing ultrasounds and we see how big your ovaries are.”

Gracia adds that if you have tons of follicles, she may give patients more specific instructions, like avoiding strenuous exercise that might lead to twisting the ovaries or that can be very dehydrating. This includes running, along with high-intensity interval training and even power yoga. Walking and low-impact exercise Does running affect fertility.

The more follicles you have the higher risk for ovarian torsion, which is when the ovary twists, cutting off blood flow. Symptoms include a sharp pain in the lower abdomen, nausea, and vomiting. Treatment involves surgery to untwist the ovary. In severe cases, if the ovary is twisted for too long resulting in necrosis, it requires surgery to remove the ovary.

Monitoring your body and taking physical cues on when to scale back and when to cease training, along with what your doctor advises you to do, is of utmost importance to prevent ovarian torsion from occurring.

“Torsion can happen really anytime,” Budinetz says. “It can even happen without IVF, but that’s really less than 1 percent. With IVF, if you’re someone who has a very high AMH (Anti-Müllerian hormone, which is produced in the ovaries and testes) or if you have polycystic ovary syndrome, you’re a high responder. You’ll likely have lots of follicles and become bloated as your ovaries swell, which increases your risk of torsion.”

“We don’t want you overexerting yourself to the point where you’re doing yoga to flip around and do twisty-turny moves and encourage that ovary to flip,” Budinetz adds. “The ovaries actually do kind of flop around a little bit in our body. They’re not stagnant, but if you’re encouraging that movement and the ovaries are so big that they flip over, it’s going to be hard for them to flip back.”

During both of my IVF cycles, I gradually slowed down my running pace on day four and five of stim when I felt—yes, felt—my ovaries beginning to swell as my hormone levels started peaking. It’s kind of like running with avocados bouncing in your waistband. When I stopped running, I walked on the treadmill or outside everyday, logging at least 10,000 steps at 20-minute pace. I even walked 10K steps hours after my first egg retrieval.

When can I get back up to speed with marathon training.

Another general IVF risk is ovarian hyperstimulation syndrome (OHSS), which happens when the ovaries are overstimulated by hormone injections, resulting in over-swelling and fluid leakage in the abdomen. My doctor started me on a pill, cabergoline, the day of my trigger shot (two days before retrieval) to help prevent OHSS from happening.

What are the risks of IVF stimulation Cleveland Clinic, OHSS happens in about 5 percent of women going through IVF, but look out for symptoms like abdominal pain, bloating, slight weight gain (like more than 2 pounds per day), and nausea. Severe cases lead to symptoms like excessive weight gain, severe nausea, vomiting, and abdominal swelling and pain, difficulty breathing, and decreased urination. These are all signs to see your medical provider right away.

Fertility doctors, including Gracia, recommend waiting two weeks before returning to your usual exercise routine after an egg retrieval. But these recommendations may change, based on your individual case.

“It depends on the kind of trigger shot and on how you responded during stimulation,” Gracia says. “If you responded with few eggs, people can honestly continue their activity throughout the entire time. But if you have a lot, then we might tell you to wait the two weeks.”

Budinetz adds the return of your menstrual cycle is another sign when things are back to normal and you can go back to your training.

“When you are done with your retrieval, you’re still going to feel a little bloated depending on how many eggs you have,” she says, which is good reason to keep your exercise routine toned down. “Once you get your period, your ovaries should be back down to size and you can go hardcore until the transfer (when an embryo is implanted in the uterus).”

What Is a Healthy Body Fat Percentage.

This is when I must come clean: I didn’t wait to run two weeks after both retrievals. I returned to running four days after my first retrieval, three after my second. (I didn’t run for nine days during my first cycle, eight days during my second.) I also raced a five-miler at 6:32-pace, coming in second woman, two weeks after my first retrieval. My period started that night.

But Moravek says the two-week rule doesn’t apply to everyone.

“I tell people they can go back to their normal activities the next day if they feel good,” she says. “If I’m worried that they’re hyperstimulated, then I’ll have a very different tune. But you’ll know that because then I’m asking you to [monitor daily weight gain] and watch your urine output. But otherwise I say just do what feels good.”

On another note, if you’re planning on having an embryo implanted weeks after egg retrieval, know that you don’t have to remain inactive after the transfer. All of the experts I spoke with want to put to bed the recommendation to stay still for three days after implantation to increase chances of conception.

“There’s no evidence for that, and it actually drives me a little crazy,” Gracia says. “We’re confining women to this state of inactivity for no good reason. It used to be way worse. We used to have people lay down on the transfer table for half an hour after the transfer with no evidence until there was a randomized trial that compared women who got up right away versus laid down. They found the women who got up right away actually had a higher chance of pregnancy. So clearly laying down did not help.”

Moravek puts what’s happening during implantation into perspective when it comes to activity.

“There is no need to lay flat or put your butt up in the air or rest or anything after an embryo transfer,” she says. “It’s microscopic. It’s too small to be subjected to significant gravity or anything like that. We actually know that after we put the embryo in, it actually bounces around the uterus for a day or two before it finds its final resting place. So, just do your normal stuff. Do what feels good.”

Before my second retrieval, I was at the height of marathon fitness, adding strength work and yoga RW+ Membership Benefits long runs. (I ran a 13-miler 17 days post-second retrieval.) As of this writing, I have days to go before racing.

Because of my history—I typically run multiple marathons a year—my conditioning allowed me to return to training after IVF. The transition wasn’t smooth, but it’s not impossible. I feel confident about toeing the starting line on Patriots’ Day, though I doubt I’ll PR this year... but you never know.

Amanda Furrer

Test Editor

Amanda Furrer, Runner’s World test editor, studied journalism at NYU and writing at Emerson College. She has reviewed gear and covered other topics in the running space for almost 10 years. Since 2013, she has consecutively run the Boston Marathon. She also has a master’s degree in gastronomy from Boston University and was formerly a professional baker for two years before hanging up her apron.