How to pace your ultramarathon (updated in 2025)

What Is Ultra Pacing — and Why It Matters

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 minimize excessive slowing and to 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.

Recent reviews show pacing strategies differ by distance, terrain, experience, and runner level (fast vs slow).

Key Insights & Recent Findings

Here are some important research-based lessons to integrate into your pacing approach:

Finding	What It Means for You
Faster runners tend to pace more evenly	In ultramarathons and longer events, elite and higher-performing runners show less variation in pace between segments; they avoid going too hard early. journalajarr.com+2ResearchGate+2
Elevation (uphills/downhills) strongly affects pacing	On trail ultras, how you manage climbs & descents matters: better finishers run downhills faster (relative) and ease up more on uphills; slower runners fall behind especially on descents as the race goes on. PMC+1
Positive pacing (gradual slowing) is common	Many ultra runners gradually slow over the course (a “positive pacing” profile). This is exacerbated on tougher terrain. Nature+2Human Kinetics Journals+2
Run-walk strategies help manage fatigue	Planned walk breaks can extend your endurance, lower muscle damage, and help maintain form, especially late in the race. Purple Patch Fitness+2Runner's World+2
Physiological stresses accumulate slowly	In long, lower-intensity efforts (even walking), markers like lipids, stress signals, and muscle damage still shift over time. Duration sometimes has more impact than intensity. PMC
Terrain-specific pacing gaps widen late	As an ultramarathon progresses, faster runners maintain performance better on downhill segments, while slower runners tend to lose more time. PMC+1
Nutrition and pacing are interlinked	Over-pacing early may reduce digestive efficiency and impair carbohydrate intake, harming your ability to maintain speed later. PMC+1

A Simpler Pacing Framework

Here’s a more user-friendly guide to pacing, including stress tests, pacing zones, and adjustments.

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).

• For example: if your training long runs suggest you can hold, say, 7:00 min/mile for many hours, allow for some buffer (slower) when race day conditions are tougher.

2. Use race segments or “blocks” rather than thinking of the whole thing

Break the ultra into mini-goals: e.g. 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.” Carmichael Training Systems

3. Factor terrain and hills

• 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. Let your downhill pace be a recovery if possible.

• Remember that elevation amplifies pacing variation: the difference between fast and slow runners is often greatest in downhill segments late in an ultra. PMC+1

4. Accept some slowing (positive pacing) but control it

Don't expect to run at the same pace nonstop. Small gradual decline is normal, but if your pace craters, that’s a pacing mistake.

5. Use planned walk breaks (if applicable)

Instead of waiting until you have to walk, schedule brief walk intervals before fatigue hits. This helps reset fatigue and maintain form. Purple Patch Fitness+2Runner's World+2

6. Be flexible and adjust mid-race

If you're feeling strong, pick up pace. If you're fading, slow more or increase walk intervals. Keep watching your body more than your splits.

Pacing Strategies by Type of Competitor

Here are tailored suggestions for fast runners, slower runners, and walkers.

For Fast / Experienced Ultra Runners

These runners often have better fitness margins, so their pacing goals differ somewhat.

Strategies:

• More even pacing: Avoid overzealous starts. Try to maintain steady relative intensity. ResearchGate+2journalajarr.com+2

• Smarter use of walk breaks (if used): Use brief walk breaks < 30 seconds — for example, walk through aid stations, steep climbs, or midday heat zones rather than full-blown walk segments.

• Use surges intentionally: On easier terrain (flats or mild downhill), you can increase pace briefly, but don’t kill yourself — maintain enough reserve.

• Manage pacing variability: Too much fluctuation (going hard then easing brutally) is less efficient. Keep smooth transitions. Nature+1

• Segment pacing: For races like Western States, research shows pacing varies by checkpoint, largely influenced by elevation. Nature

• Watch for crash zones: Many pace mistakes happen when runners try to “bank” time early. That’s risky. Precision Hydration+2Carmichael Training Systems+2

Example Plan (fast runner):

• First 10–15 %: settle in, don’t chase others.

• Middle 60 %: hold a consistent relative effort, adjusting for terrain.

• Final 25 %: slow gradually but maintain focus and controlled effort; pick up pace if energy allows.

For Slower / Midpack Ultra Runners

Slower or mid-level runners (non-elite) have less margin for error, so pacing prudence becomes even more critical.

Strategies:

• Err on the side of conservatism early: Don’t try to keep up with faster runners; you’ll pay for it later.

• Use run-walk from the start: Many slower runners benefit from adopting walk breaks early—and keeping them consistent.

• Shorter run segments, more frequent walks: E.g., run 5–8 minutes, walk 1 minute (or similar) vs long run blocks. This helps manage fatigue.

• Walk climbs aggressively: Climbing is often where slower runners lose most relative time; walking is often more efficient uphill.

• Allow more built-in slowing: Accept that your pace will drop more toward the end, and plan for it.

Example Plan (slower runner):

• Start with a run 6–8 min / walk 1 min rhythm.

• On steeper hills or rough terrain, walk longer.

• After halfway, you may shift to run 4–5 min / walk 1 min, or even 3 min / walk 1 min as fatigue increases.

• Be ready to slow your “run” pace selectively rather than force yourself.

For Walkers / Ultra Walk/Joggers

For those whose primary mode is walking (or alternating walking + power walking), pacing is different yet still important.

Strategies:

• Optimize walking efficiency and gait: Focus on good posture, stride, cadence, and minimizing wasted motion. Walking economy matters.

• Set a steady walking pace you can sustain: Rather than thinking “go fast early,” pick a walking speed that conserves energy for many hours.

• Use “power walking” when possible: On flatter terrain, incorporate strong walking strides rather than slow shuffling.

• Alternate brief running segments (if capable): If you are strong and terrain allows, you might mix short runs into your walking strategy (e.g. 1 minute run every 10 minutes walking).

• Plan for terrain changes: Walk uphills; on descents, you might transition into a light jog or fast walk.

Example Plan (walker):

• Begin at a brisk walking pace that you expect to maintain.

• After 60–90 minutes, if fresh and terrain allows, add 30 seconds to 1 minute of running every 5–10 minutes.

• Walk all climbs; on flats / gentle descents, try to jog lightly if it doesn’t risk injury.

• Monitor your pace drift; if you slow too much, reduce or drop the run bits and focus purely on steady walking.

  
  

Sample Pacing Templates

Here are rough templates to adapt:

Type	Early Phase	Mid Phase	Late Phase
Fast Runner	Run steadily, minimal walking	Maintain steady effort, small surges	Controlled slowing, push when possible
Slower Runner	Run 6–8 / walk 1	Switch to 5–6 / walk 1 or 4 / walk 1	More frequent walking (3 / walk 1), slower runs
Walker / Jogger	Steady walking or walk + short runs	Brisk walking + occasional run	Conservative walking, minimal running, maintain form

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

Common Mistakes & How to Avoid Them

1. Starting too fast (“banking time”). Many ultra runners push early to build a buffer, but this often leads to collapse later.

2. Ignoring terrain effects. Treating the course as flat while ignoring hills will drain energy quickly.

3. Overly rigid walk/run splits Some try to stick to exact ratios even when conditions change. Be flexible.

4. Neglecting walking technique. Poor walking gait or biomechanics waste energy, especially when walking makes up a large share of time.

5. Letting pace drift uncontrolled. Without regular checks or “micro resets” (walk breaks, hydration, posture resets), your form and speed will degrade.

Integrating Pacing with Nutrition & Hydration

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

Hence:

• Keep your effort moderate enough that you can still take in food and fluids.

• Use walk breaks, aid stations, or slowed segments to eat, drink, and reset.

• Monitor your blood glucose or energy levels (if possible) to detect dips before they cause collapse.

  
  

Final Tips (for Any Runner / Walker)

• Practice your pacing strategy in training — don’t wait until race day.

• Use aid stations wisely — slow down, refuel, walk while eating.

• Break the race into mental segments — focus on what’s immediately ahead, not the entire distance.

• Listen to your body — if form degrades or you feel early fatigue, ease up sooner.

• Adjust on the fly — conditions, fatigue, terrain may force you to change plans.

• Train walking — many ultra runners underestimate how much time they will walk; practice walking economy.