Olfactory Pacing: Using Scents to Manage Your Effort in Ultra-Trail Running

Pacing in Ultra-Trail: When Numbers Are No Longer Enough

Hey there, fellow trail enthusiast! If you're like me, you've spent hours analyzing your running data: heart rate, pace, elevation gain, power... Your GPS watch has become an extension of your arm, a digital coach whispering numbers in your ear. It's great, right? We have incredible tools to optimize our performance. But on an ultra-trail, this well-oiled machine can quickly seize up. Who hasn't seen their heart rate inexplicably soar on a climb, or their target pace become an unattainable goal due to muddy terrain or a sudden heatwave?

The ultra is a school of humility. It's a discipline where the mind, sensations, and environment play a huge role. The numbers, as precise as they may be, only tell part of the story. They don't tell you that your stomach is starting to knot up, that your morale is dropping as night falls, or that the stress of a cutoff time is making you breathe too quickly. That's when I started exploring other paths, more intuitive methods to stay connected to my body and my effort. And one of the most surprising and effective ones I discovered is olfactory pacing.

The idea might seem outlandish at first. Managing your effort with smells? Really, Charly? Yes, really. And I'm going to show you how this sense, often relegated to the background, can become your best ally for crossing mountains, nights, and low points. We're going to set technology aside for a bit to reconnect with something much more primal and powerful: our own senses.

The Sense of Smell: Your Ignored Brain Superpower

Before diving into the practical side, let me share a little gem about how our nose works. It's not just an appendage that helps us appreciate our morning coffee or detect an overflowing trash can. The sense of smell is our most direct link to the brain, and more specifically, to some very old and powerful areas.

A Direct Highway to Your Emotions and Memory

When you breathe in a scent, volatile molecules enter your nostrils and stimulate receptors in your olfactory bulb. The information doesn't take a long detour through various brain relays like sight or hearing. No, it goes straight to the limbic system, the headquarters of your emotions (thanks to the amygdala) and your long-term memory (thanks to the hippocampus). That's why the smell of chalk can instantly take you back to your elementary school classroom, or the scent of a cake can remind you of Sundays at your grandmother's. It's the "Proustian moment" effect!

And for us endurance runners, this is crucial information. If a scent can change your emotional state or revive a powerful memory in a fraction of a second, imagine what it can do for your perception of effort, your motivation, or your stress level mid-race! A scent can, almost instantly:

• Calm a racing heart rate.
• Increase concentration on a technical night descent.
• Provide a mental boost when you're hitting a wall at the 120th kilometer.
• Anchor a feeling of well-being and control.

Olfactory pacing, therefore, is the art of consciously using this superpower to influence your physical and mental state during exertion. It's a way of communicating with your brain in a language it understands instinctively, without going through the filter of logic or sheer willpower, which can be quite dulled after 15 hours of running.

Olfactory Pacing: The Practical, Step-by-Step Guide

So, convinced? Perfect. Now, let's get down to business. How do we put this into practice? It happens in three stages: choosing your weapons (the scents), training with them, and deploying them on race day. It's simpler than you think.

Step 1: Create Your Personal "Olfactory Anchors"

An olfactory anchor is a scent that you will intentionally associate with a specific mental or physical state. The goal is to create a conditioned reflex. The idea isn't to pick a scent at random, but to choose it based on the effect you're looking for and, most importantly, your own preferences. What works for me won't necessarily work for you. Experimentation is key!

Here are a few categories to guide your choices, with examples of commonly used essential oils:

1. The CALM / BASE PACE Anchor: This is your metronome, your reference point for your cruising speed. The scent that tells you: "Breathe, everything is fine, you're in the right zone."
   • Suggestions: True Lavender, Petitgrain, Roman Chamomile, Sweet Marjoram.
   • My personal choice: Lavender. It reminds me of holidays in Provence and has an almost immediate effect on my breathing. I use it on long, steady climbs to keep from getting carried away.
2. The CONCENTRATION / FOCUS Anchor: For moments that require maximum attention. A technical descent, a night section, complex navigation.
   • Suggestions: Peppermint, Rosemary (Cineole type), Eucalyptus Radiata, Bay Laurel.
   • My personal choice: Peppermint. It's a real mental jolt. The fresh, striking effect instantly awakens the senses. Ideal when fatigue starts to creep in after sunset.
3. The ENERGY / BOOST Anchor: When you feel your energy waning, when your morale is low. This is your olfactory "mental gel."
   • Suggestions: Lemon, Grapefruit, Black Spruce, Ginger.
   • My personal choice: Lemon. It's fresh, zesty, and evokes vitality. A good inhale before tackling a major difficulty or leaving an aid station, and it helps you get back on the right foot.
4. The COMFORT / "HOME" Anchor: This is your olfactory security blanket. The scent that brings you back to a feeling of safety and warmth. To be used in moments of deep doubt or extreme loneliness in the middle of the night.
   • Suggestions: Vanilla, Cinnamon, a drop of your partner's perfume, the smell of your morning coffee... Be creative!
   • My personal choice: A touch of vanilla. It reminds me of my childhood cakes. It's a nostalgic and incredibly soothing scent when everything seems difficult.

Step 2: Conditioning During Training

This is the most important step, the one that will turn a simple scent into a real pacing tool. You can't just show up at the starting line with your vials without ever having used them before. Your brain needs to learn and solidify the associations.

The protocol is simple. During your training runs, integrate the use of your anchors:

• Long run at base endurance pace: Every 30-45 minutes, take a few seconds to deeply inhale your CALM anchor. Do it when you feel good and relaxed. The goal is to associate this scent with a state of well-being and control at low intensity.
• Hill repeats or VMA session: Just before starting your intense effort, take a good whiff of your ENERGY anchor. Repeat before each repetition. This way, you associate the scent with mobilizing your resources.
• Technical or night run: When you approach a section that requires vigilance, use your CONCENTRATION anchor. Do it proactively, just before the difficult section begins.
• At home, at rest: In the evening, during a moment of relaxation, breathe in your COMFORT anchor. The goal is to associate it with a feeling of security and recovery.

Repeat this process over several weeks. The more you do it, the faster and more automatic your brain's response will become. You'll see, it's quite amazing. You'll quickly feel that simply smelling lavender at the start of a run immediately puts you in the right mental rhythm. If you're curious about how this type of conditioning can influence your motivation, I invite you to read this article on the effect of scent training on motivation in trail running.

Step 3: Strategic Deployment on Race Day

Race day is here. You have your anchors, and your brain is conditioned. Now, how do you use them effectively without it becoming a hassle?

First, the gear. How do you carry your scents?

• The terry cloth or fabric wristband: This is my favorite method. A few drops on a wristband. It's simple, lightweight, and you just have to bring your wrist to your nose. The downside: the scent dissipates with sweat and rain. You have to reapply it regularly.
• A cloth handkerchief in a zip-lock bag: You can soak a small piece of fabric for each anchor and keep them in separate, well-labeled bags in your pack. It's effective but a bit less practical to handle while running.
• The inhaler stick or rollerball: Very practical. The rollerball allows for easy application on the wrists or a neck gaiter. The stick is discreet and preserves the scent well.

Next, the timing. The key is anticipation. Don't wait until you're in the red to use an anchor. Use them as preventive tools:

• Before a long climb: An inhale of your CALM anchor to remind yourself not to start too fast.
• As night approaches: A few minutes before your headlamp becomes essential, a whiff of your CONCENTRATION anchor to prepare your brain for the change.
• Leaving an aid station at km 100: Even if you feel good, a dose of your ENERGY anchor to restart the engine mentally.
• When you feel a spike of stress: A cutoff time is getting close, a pain appears... This is the moment to pull out the CALM anchor and take 3 deep breaths to bring the pressure down.

Olfactory pacing doesn't replace a good nutrition or hydration strategy, but it complements it wonderfully by acting on a lever that is too often forgotten: the mind and the nervous system.

Beyond the Bottle: Using Nature's Scents as Guides

Olfactory pacing isn't limited to the essential oils you carry. Nature itself is a huge reservoir of olfactory information that can help you manage your effort. Learning to decode them means connecting even more deeply with your environment and your race.

The scent of the forest, your natural calm anchor

When you enter a pine or fir forest, what do you smell? That woody, resinous, fresh scent... It's not just pleasant. The volatile compounds emitted by trees (phytoncides) have a proven effect on reducing stress and blood pressure. This is the principle of "Shinrin-yoku" or Japanese forest bathing. In an ultra, a forest section is a blessing. Take the opportunity to breathe deeply. The smell of humus, damp earth, mushrooms... These earthy scents are incredibly effective for "grounding" you, re-centering you, and calming ragged breathing. It's your calm anchor, courtesy of nature.

Petrichor, your brain's reset button

You know that incredible smell that rises when rain falls on dry earth? It's called petrichor. It's a powerful, almost electric scent. During a race, the arrival of rain is often a tricky moment. But if you focus on this smell, it can act as a real reset button. It marks a transition, a change. It cleans the air and can give you a mental boost, a feeling of renewal. Instead of cursing the rain, breathe it in!

Flowers and plants, your course markers

On courses you know or have scouted, smells can become spatio-temporal landmarks. The sweet scent of broom in the spring might signal that you're approaching a sunny section. The fragrance of rhododendrons at high altitude tells you the summit isn't far. The smell of cut hay in a valley confirms you've descended properly. Learning to associate these scents with specific sections of the course helps you situate yourself mentally, manage your effort better, and anticipate what's coming. It's an olfactory mind map, much more vivid than a course profile on your watch.

Community Testimonials: They've Tested It for You

So you don't think I'm the only crazy one sniffing my wrist in the middle of the mountains, I've gathered some feedback from fellow trail runners who have tried the experiment:

Julie, UTMB® finisher: "I was skeptical at first. Charly told me about it and I wanted to give it a try. I had a small peppermint rollerball. On the long climb up the Grand Col Ferret, in the middle of the night, monotony and sleepiness were starting to take over. Instead of having another coffee, I applied a bit of peppermint to my temples and wrists. The effect was immediate! A real jolt, like someone had switched on a light inside my head. It helped me stay super focused on the descent that followed. It's become an essential item in my trail pack."

Marc, a fan of technical trails in Provence: "My problem is that I always start too fast. My heart races and I pay for it dearly later. I associated the smell of rosemary, which I find everywhere on my training trails, with a calm and controlled pace. In races, on different terrains, I carry a handkerchief with rosemary essential oil. As soon as I feel myself getting too worked up, I breathe it in. It's my signal to slow down, calm myself, and enjoy the moment. It's become my personal safety brake."

Mistakes to Avoid and Final Practical Tips

Like any technique, olfactory pacing requires a bit of practice, and there are a few pitfalls to avoid to ensure it remains a pleasure and an asset.

• Not testing: The number one mistake. Trying a new essential oil on race day is a very bad idea. A scent you love at rest can become nauseating during intense effort. Test everything, and on long runs!
• Overdosing: Don't use too much! The goal is to have a subtle scent available when you need it, not to turn yourself into a walking perfume shop. A single drop is often enough. Too much scent can overwhelm your sense of smell and even make you feel sick.
• Applying it to your skin: Be careful, pure essential oils can be irritating to the skin, especially with sweat and sun exposure (some are photosensitizing, like citrus oils). Always prefer a carrier like fabric.
• Relying on it completely: Olfactory pacing is a complementary tool. It doesn't replace your nutrition plan, your hydration, or listening to your body's basic signals (pain, muscle fatigue, etc.). It's the cherry on top of your race strategy cake.

This approach is much more than a performance hack. It's an invitation to run differently. To be more present, more attentive. It's about transforming an endurance event into a true sensory experience. By connecting with scents, you connect with yourself and the world around you in an incredibly rich way.

So, the next time you pack your bag, consider slipping your olfactory anchor in next to your gels and your flask. You might just be surprised by the power contained in those little drops.

Now it's your turn!