How to Pace Your Ultramarathon

When you run an ultramarathon — anything significantly beyond marathon distance — one of your biggest challenges is how to distribute your effort over many hours so you don't collapse late. Pacing is the art of managing your speed, effort, rest, walk breaks, fuel, and terrain to minimise excessive slowing and preserve energy. Poor pacing can lead to big slowdowns, excessive fatigue, injury risk, or getting cut off by time limits. Good pacing makes the difference between a strong finish and a painful crawl.

What Is Ultra Pacing — and Why It Matters

Pacing in ultras is not simply about running at a steady speed. It's a dynamic system that must account for terrain, time of day, temperature, your training background, how well you fuelled, and dozens of micro-decisions every hour. Recent research confirms that pacing strategies differ significantly by distance, terrain, experience, and runner level — what works for an elite 100-miler can be completely wrong for a mid-pack 50km runner.

Key Insights & Recent Research Findings

Here are the most important research-backed lessons to integrate into your approach:

A Simpler Pacing Framework

Here is a practical step-by-step guide to pacing, including effort zones and how to adjust on the fly.

1. Estimate a sustainable base pace Start with what you believe is a pace you can hold for many hours — not your fastest, but comfortably hard. If your training long runs suggest you can hold, say, 7:00 min/km for many hours, allow for a buffer (going slower) when race day conditions are tougher.
2. Use segments, not the whole distance Break the ultra into mini-goals: to the first aid station, to the next climb, or between 5–10 km blocks. This keeps things manageable mentally. Many coaches call this "run the mile you're in."
3. Factor terrain and hills actively On climbs, slow down or switch to walking early so your heart rate doesn't spike unsustainably. On descents, you can make up time — but don't go all out and wreck your quads. Research shows the difference between fast and slow runners is often greatest in downhill segments late in an ultra.
4. Accept some slowing — but control it Don't expect to maintain the exact same pace throughout. Small gradual decline is normal. If your pace craters, that's a pacing mistake that needs correcting now, not later.
5. Use planned walk breaks Instead of waiting until you have to walk, schedule brief walk intervals before fatigue sets in. This helps reset muscular fatigue and maintain form throughout the race.
6. Be flexible and adjust mid-race If you're feeling strong, pick up pace. If you're fading, slow or increase walk intervals. Keep watching your body more than your splits — your body is always right.

Pacing Strategies by Runner Type

The right pacing strategy differs significantly depending on your experience level and target finish time.

Example Race Plans by Type

Fast runner: First 10–15%: settle in, don't chase. Middle 60%: hold consistent relative effort, adjusting for terrain. Final 25%: controlled slowing, maintain focus, push when energy allows.

Slower runner: Start with run 6–8 min / walk 1 min. Shift to run 5–6 min / walk 1 min or 4/1 at halfway. More frequent walking in the final third — expect the run segments to get shorter rather than forcing pace.

Walker/jogger: Begin at a brisk sustainable walking pace. After 60–90 minutes, add 30-second to 1-minute running intervals every 5–10 minutes if fresh. Walk all climbs; light jog on flat/gentle descents. Drop run intervals when tired — prioritise walking economy.

Sample Pacing Templates

These are starting blueprints — adjust based on how you feel, terrain, weather, and nutrition.

Common Mistakes & How to Avoid Them

• Starting too fast ("banking time"). Many ultra runners push early to build a buffer. This almost always leads to collapse later. The buffer disappears and you pay double.
• Ignoring terrain effects. Treating a hilly trail course as if it were flat will drain energy quickly. Every significant climb needs to be factored into your effort plan.
• Overly rigid run/walk splits. Sticking to exact ratios even when conditions change is a mistake. Be flexible. The plan is a guide, not a rule.
• Neglecting walking technique. Poor walking gait wastes energy, especially when walking makes up a large proportion of your total time. Practice efficient walking in training.
• Letting pace drift uncontrolled. Without regular resets — walk breaks, aid station pauses, posture checks — your form and speed degrade without you noticing until it's too late.

Integrating Pacing with Nutrition & Hydration

Pacing doesn't stand alone — your ability to digest, absorb, and use fuel is directly affected by how hard you push. Research shows that over-pacing can compromise gastrointestinal function, reducing carbohydrate absorption and harming later performance.

Keep your effort moderate enough that you can still take in food and fluids. Use walk breaks, aid stations, and slowed segments as opportunities to eat, drink, and reset. If you're pushing so hard that you can't eat, you're going too hard.

Final Tips for Any Ultra Runner

• Practise your pacing strategy in training — don't wait until race day to figure out your run/walk ratio.
• Use aid stations wisely — slow down, refuel, walk while eating. A 90-second aid station pause costs very little time and can save your race.
• Break the race into mental segments — focus on what's immediately ahead, not the total distance remaining.
• Listen to your body above all — if form degrades or you feel early fatigue, ease up sooner rather than later.
• Train walking — many ultra runners underestimate how much time they will spend walking. Walking economy and efficiency genuinely matter.
• Adjust on the fly — conditions, terrain and fatigue will all force changes. The runners who adapt well finish strong.

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