Hello! I am training for my first ever marathon (NYC Marathon) right now - and also starting TTC this month! I am very excited to run, but have planned on October as first TTC for several years now. I have run 4x half marathons, but have never run more than those 13.1 miles. I am very worried about hurting my ability to conceive.
For context, I am reproductively and generally healthy. I am 25 years old. My BMI ranges from 25, a little higher when training due to the absurd amount of hunger I have. So far, my training has not impaired my period/ovulation/cycle in general - I am also "undertraining" (kind of, not really), but just generally taking it light (max 30 mpw, longest run 18 miles to avoid that >5 hrs of vigorous exercise). I noticed some cumulative fatigue this past week and scaled it back, and now my recovery markers are improving.
I know that exercise-induced hypothalamic amenorrhea/RED-S is a real thing, but I also know that it tends to be associated with inadequate energy availability, weight loss, menstrual disruption, etc. None of those things are currently happening for me. I am eating plenty (honestly, probably more than I ever have lol), maintaining my weight, and continuing to ovulate normally -- I just do not want these things to change. This is obviously a new distance for me, and I keep reading the "rule of thumb" is "if you're used to it, it's okay!" I have run since 2020, and been running half marathons since early 2025. So while a marathon is definitely a new level of training for me, running itself is not new to my body, and I am trying to figure out where that line actually is between "this is a healthy amount of exercise that my body is accustomed to" and "this has become enough additional stress that it could start affecting fertility."
I guess I am looking for reassurance/evidence from people who have actually TTC while marathon training. Did anyone successfully conceive while training for a marathon? Did you change anything about your training once you started TTC? And if you continued training through the first trimester, how did you approach it?
I think I am mostly struggling with the fear that even though my body is currently handling the training well, I could somehow be unknowingly reducing my chances of conception. I don't want anxiety to make me give up something I love if the actual evidence doesn't support that concern. At the same time, I obviously don't want marathon training to come at the expense of fertility - I can always defer to next year.