Race Day & Your Period: What Every Female Runner Needs to Know

Dayna Player Robinson
Apr 29
3 min read

Race Day & Your Period:

What Every Female Runner Needs to Know

Let's have a minute for some girl talk. . . . You’ve trained hard. You’ve dialed in your nutrition. You’ve got your playlist ready and your race-day gear packed. But there’s one thing many female runners forget to consider: your menstrual cycle.

If your period is scheduled to arrive around race day—or is already knocking on the door—don’t panic. You’re not alone, and you’re not doomed. But you do need to understand what’s happening in your body and how to support it.

Let’s break down what you should know—straight from experts like Dr. Stacy Sims, Mindy Pelz, Molly Galbraith, and Lara Briden’s Period Repair Manual—so you can run strong, period or not.

🩸 The Phases of Your Cycle & Performance

Your cycle isn’t just about your period—it’s a monthly hormonal symphony with four phases: menstrual, follicular, ovulation, and luteal. Here's how they can impact your training and race day:

1. Menstrual Phase (Days 1–5)

You're bleeding, estrogen and progesterone are at their lowest. The good news? According to Dr. Stacy Sims, your hormones are similar to a man’s during this phase—which can mean increased pain tolerance and better access to carbs. That’s a win for race day!

➡️ Support Tip: Don’t skip carbs. Fuel well pre-race, and if cramps are an issue, magnesium and turmeric (Mindy Pelz loves this combo!) can help reduce inflammation.

Need proof you can crush it during your period? Look at elite marathoner Emma Bates — she hit a massive personal best at the Boston Marathon while racing on her period. She’s spoken openly about how she used knowledge of her cycle—not fear of it—to optimize her race strategy. You are absolutely capable of performing at your best, even during your bleed.

2. Follicular Phase (Days 6–14)

Estrogen is rising, and so is your energy. Strength, speed, and motivation are often higher here. If race day falls here, enjoy the boost!

➡️ Support Tip: Molly Galbraith encourages female athletes to lean into this phase—use it for hard efforts and peak performances.

3. Ovulation (~Day 14)

Estrogen peaks and testosterone gets a boost too. You may feel strong—but some women also feel bloated or experience joint laxity, which can increase injury risk.

➡️ Support Tip: Hydrate well and warm up thoroughly. Briden points out that blood sugar may be less stable here—so don’t skimp on fueling.

4. Luteal Phase (Days 15–28)

Progesterone rises, estrogen dips. You may feel sluggish, hot, and hungrier. You might retain water. Sound familiar?

➡️ Support Tip: Dr. Sims recommends increasing sodium and fluid intake leading up to race day during this phase to help with thermoregulation and hydration. Lara Briden adds that slow-digesting carbs and magnesium can help fight cravings and bloating.

What If Race Day Is the First Day of Your Period?

Not ideal, but also not bad!! Some women perform well, others struggle. Here’s what to do:

Plan ahead: Use what’s familiar, but I personally think the cup is the best thing invented for us women!
Cramp management: NSAIDs like ibuprofen, used cautiously, can help. Natural alternatives include ginger, magnesium glycinate, and hydration with electrolytes.
Fuel well: You’ll burn through glycogen faster, so eat more pre-race and take your carbs on schedule.

Red Flags: When to Pay Attention

Lara Briden’s Period Repair Manual emphasizes that a healthy period is a vital sign. If you’ve lost your period (amenorrhea), have extremely irregular cycles, or experience debilitating PMS—your training might be too much, your fueling too little, or your hormones out of balance.

➡️ Your period is not a nuisance—it’s a powerful indicator of how your body is responding to stress, training, and nutrition.

Final Thoughts: Your Cycle Is Your Superpower

Female physiology is not a liability—it’s a performance edge if you learn to train with it. Dr. Stacy Sims put it best: “Women are not small men.” Understanding your unique hormonal shifts allows you to adapt, plan, and race with more power and confidence.

Your period doesn’t have to slow you down—it can be part of your strength story.

Happy running

Dayna - your fav. Exercise Physiologist