Trail Notes | Female Athlete Racing

Racing With

Your Cycle

You may not be able to choose where your cycle lands on race day. But you can choose how you prepare, how you pace, how you fuel, and how you respond to the body you have on the start line.

Ahead of big trail events, one question comes up again and again in our Her Trails community.

What if my race falls right before my period? What if race day is day one, two or three of bleeding? What if my heart rate is higher than usual? What if my perceived effort feels different? What is normal, and what might mean I am going out too hard?

These are not small questions. They sit at the heart of female endurance racing. Because women do not get to choose race dates around their cycle. We line up with the body we have on the day, in the weather that arrives, on the terrain in front of us. The aim is not to control everything. The aim is to hold what we can control and influence what we can.

Start with what is true

The menstrual cycle does not affect every woman in the same way. Some athletes feel strong once bleeding begins. Some feel flat, heavy, emotional or crampy. Some notice higher heart rate in the days before their period. Some notice more gut sensitivity, poorer sleep, lower confidence or feeling hotter than usual.

The research tells us that menstrual cycle phase does not create a fixed performance ceiling. Across groups of women, the average performance effect is usually small. But individual symptoms can be very real, and in a long trail race, symptoms matter because they influence decision-making, fuelling, comfort, temperature regulation and pacing.

This means the most helpful question is not, “Can I race well in this phase?” The better question is, “What does my body need me to manage well today?”

There can be strengths in every phase

Cycle awareness is often spoken about through the lens of challenge. PMS. Cramping. Fatigue. Higher perceived effort. Gut changes. And yes, those things can be real. But the menstrual cycle is not only a risk map. It can also give you useful information about where your body may feel capable, responsive, steady or strong.

Some women feel sharper, stronger and more confident in the first half of their cycle. Some feel relief and renewed energy once bleeding begins. Some find the pre-menstrual phase brings more emotional honesty, deeper body awareness and a stronger ability to protect their boundaries. Some notice no clear pattern at all.

The point is not to label one phase as good and another as bad. The point is to know your own patterns well enough that you do not arrive at the start line already defeated by an assumption.

What can shift pre-menstrually

In the immediate pre-menstrual phase, many women notice that the same effort can feel more expensive. This does not mean your fitness has disappeared. It may mean your body is carrying a higher symptom load.

None of this automatically means you are racing badly. It means your body may need a more conservative opening, tighter fuelling, earlier cooling decisions and less attachment to what your watch usually shows.

What can shift on day one to three of bleeding

For some women, the first few days of bleeding bring relief. For others, they bring cramps, back pain, heavier bleeding, gut changes, nausea, fatigue, headaches or a feeling of heaviness through the pelvis and legs.

In a trail race, this matters because discomfort can affect how you breathe, climb, descend, eat, drink and make decisions. It can also make you more likely to overreact early, either by pushing to prove you are fine or by assuming the day is already lost.

The middle ground is stronger. Acknowledge what is present. Then move to what you can influence.

Watch the story you attach to your cycle

One of the biggest risks on race day is not the cycle phase itself. It is the story we attach to it before the race has even begun.

If you tell yourself, “I am pre-menstrual, so this race is going to go badly,” you may begin the day scanning for proof that you are already struggling. If you tell yourself, “I am bleeding, so I have no chance of feeling strong,” you may miss the moments where your body is actually settling, adapting and finding rhythm.

This does not mean pretending symptoms are not there. It means not allowing symptoms to become the whole story.

A more useful story might be: “My body may need a little more patience today. I can start with restraint. I can fuel early. I can respond to what is happening. I can keep making good decisions.”

Control the controllables

You cannot control when your period arrives. You cannot control the exact phase your body is in on race morning. You cannot control whether the forecast shifts, whether the trail is wet, whether the stairs feel endless or whether the first climb feels more demanding than expected.

But you can influence your race through the choices you make before and during the event.

How to use heart rate without being ruled by it

Heart rate can be useful on race day, but it is not the full truth. In certain phases of the cycle, and under stress, heat, poor sleep, dehydration or high adrenaline, your heart rate may sit slightly higher than expected.

That does not mean you should ignore it. It means you should read it alongside other signals: breathing, gut comfort, temperature, mood, leg strength, coordination, ability to recover after climbs and how steady your decision-making feels.

What is normal, and what means you might be going too hard?

This is the question many athletes really want answered. The line between normal cycle-related discomfort and poor race execution can feel blurry in the moment.

The best race plan is responsive

Trail racing is already dynamic. Terrain changes. Weather changes. Underfoot conditions change. Your body changes too.

For mountain, coastal, forest or ultra-distance trail races, the safest and strongest approach is to start with enough restraint that you have room to respond. You can always build into the race. It is much harder to recover from a first third that was run with panic, ego or denial.

When the trail is wet, muddy or slippery

Cycle symptoms are not the only uncontrollable on race day. Weather and trail conditions can shift everything. If rain arrives, if the ground is slippery, or if the terrain becomes softer underfoot, your effort may rise even when your pace slows.

This is especially important for shorter trail events too, including 20 to 25 kilometre races, where it can be tempting to keep pushing because the distance feels manageable. Slippery terrain rewards patience, cadence, foot placement and control. It rarely rewards forcing pace.

Fuel early, especially if appetite is low

If you are pre-menstrual or bleeding, appetite and gut comfort may feel different. This is not the time to make your fuelling more complicated. It is the time to make it more deliberate.

Use foods and products you already trust. Eat before the race if you can. Start fuelling early in the race, before your mood drops, before your legs feel empty and before your gut becomes harder to negotiate with.

For many trail runners, smaller and more frequent amounts sit better than large, occasional intakes. If your gut becomes unsettled, simplify. Return to familiar carbohydrates, small sips, bland foods and steady breathing.

Plan your period products like race kit

Your bleeding-management plan is not separate from your race plan. It is part of your kit, your comfort and your ability to stay focused.

Race day is not the moment to try a new cup, tampon, disc, pad, period underwear or anti-chafe strategy. Use what you have tested. Carry more than your optimistic self thinks you need. Pack a small zip bag, wipes, spare underwear if needed and any disposal items required by the event.

For longer races, decide where you might change products before the race starts. Do not leave that decision until you are cold, rushed, emotional or already uncomfortable.

Pain relief, cramps and safety

If you experience period pain, make a plan before race morning. That might include heat before the start, gentle movement, breathing strategies, clothing comfort, and medication only if it is something you already know is safe for you and appropriate for ultra-distance racing.

Do not trial new medication on race day. Some pain relief options can carry additional risk during long endurance events, especially when dehydration, kidney stress, gut irritation or heat are involved. Speak with a doctor, pharmacist or qualified health professional if you are unsure what is safe for you.

If your bleeding is unusually heavy, if you are soaking through products quickly, feeling faint, experiencing severe pain, chest pain, confusion, repeated vomiting, severe shortness of breath or symptoms that feel beyond normal race discomfort, stop and seek medical help.

A simple race-day decision check

When things feel harder than expected, do not immediately decide the race is falling apart. Run a simple check first.

This is how you stay powerful in the unknown. Not by controlling everything, but by staying connected enough to respond.

If you are lining up for a race and worried about where you are in your cycle

If you are lining up for a race and your cycle is not landing where you hoped, take a breath. This does not take you out of the race. It simply asks you to race with more information, more respect for your body and more discipline in the choices you can control.

You do not need to arrive at the start line with a perfect hormonal profile, perfect weather, perfect sleep, perfect confidence or perfect conditions. That is rarely how trail racing works. You need a plan that can bend without breaking.

If your body feels different, start with curiosity rather than panic. Ask what the body is telling you. Does it need a slower first climb? Earlier fuel? More fluid? A layer removed? A product change? A moment to settle your breath?

And if the day settles, let yourself build. The point of starting conservatively is not to race small. It is to give yourself the best chance to race the whole course well.

This applies to every trail event

Whether you are racing 20 kilometres, 50 kilometres, 100 kilometres or more, you will never control every variable. That is part of what makes trail running honest. It reveals how well you can adapt.

Your cycle may influence the day. So might heat, rain, mud, sleep, stress, travel, nerves, nutrition, altitude, terrain or the energy of the people around you. None of these things have to become the whole story.

Cycle awareness is not about making women cautious. It is about making women more skilled. More informed. More prepared. More able to make strong decisions when the body gives them different data than expected.

The deeper rhythm

At Her Trails, we do not want women to feel as though their bodies are problems to overcome. We want women to understand their bodies well enough to move with more trust.

That means learning your own patterns. It means noticing how your body responds across training, racing, stress, sleep, weather and life. It means preparing without catastrophising. It means respecting symptoms without reducing yourself to them.

Your cycle may be part of your race-day story. It does not have to be the whole story.

The invitation

If your period arrives on race week, if you are pre-menstrual, if your energy feels different, or if the forecast changes and the trail becomes wet and slippery, return to the same question.

What can I hold? What can I influence? What is the next good decision?

Because strong racing is not about having perfect conditions. It is about staying connected, responsive and brave enough to work with the conditions you have.