Training for Your First Ultramarathon: The Complete Guide

What is an Ultramarathon?

An ultramarathon is any running race longer than the standard marathon distance of 26.2 miles (42.2km). While that technically means a 27-mile race qualifies, the most common ultra distances are 50K (31 miles), 50 miles, 100K (62 miles), and 100 miles.

Ultrarunning has exploded in popularity over the past decade. What was once a fringe activity for extreme athletes has become mainstream, with events ranging from flat road ultras to technical mountain races. The beauty of ultras is that they're as much about completing the journey as they are about racing - most participants aren't competing to win, they're competing to finish.

Unlike road marathons where pace is king, ultramarathons reward consistency, smart pacing, and the ability to problem-solve on the move. You'll walk. You'll eat. You might change shoes at an aid station. And that's all part of the experience.

Choosing Your First Ultra

Your first ultra should set you up for success. Here's how to choose:

Popular Distances

Trail vs Road Ultras

Trail ultras are more common and offer varied terrain, scenery, and natural aid station breaks on climbs. They're generally more forgiving on your body because the varied terrain distributes stress differently.

Road ultras are less common but can be easier to pace and navigate. The repetitive motion can be harder on joints, but you'll likely run faster times on flat roads.

For your first ultra, consider a well-organized event with good aid station support, manageable cutoff times, and terrain similar to where you train. Local running clubs often have recommendations.

Building Your Aerobic Base

The foundation of ultramarathon training is aerobic base building. Unlike marathon training where tempo runs and speedwork play major roles, ultra training emphasizes time on feet at easy, conversational paces.

The 80/20 Principle

Most successful ultra training follows the 80/20 principle: 80% of your running should be at easy, aerobic effort (Zone 2), with only 20% at higher intensities. This builds the aerobic engine you need to run for 6, 12, or 24+ hours.

Use a heart rate zone calculator to find your Zone 2 range. For most runners, this means running slow enough to hold a conversation. If you're breathing hard, you're going too fast for base building.

Time on Feet vs Mileage

Ultra training often focuses on time on feet rather than pure mileage. A 3-hour long run on technical trails might only cover 15 miles but provides excellent training stimulus. Your body doesn't care about distance - it cares about the duration and nature of the stress you're applying.

For 50K training, aim for long runs of 3-4 hours. For 100-milers, you'll want some runs extending to 5-6 hours. These don't need to be fast - the goal is adaptation to prolonged movement.

The Ultra Training Toolbox

Beyond basic mileage, these training methods are essential for ultra success:

Back-to-Back Long Runs

The signature ultra training workout. Run long on Saturday, then run long again on Sunday - typically 18-22 miles followed by 12-16 miles. This teaches your body to run on tired legs, mimicking the later stages of an ultra.

Start with modest back-to-backs (10+8 miles) and build up. The second day should feel like a shuffle - that's the point. Your legs learn to keep moving when they're already depleted.

Elevation & Terrain Specificity

If your race has significant climbing, train on hills. If it's technical single-track, find technical trails. Your body adapts specifically to the stresses you apply. Running on flat pavement won't prepare you for mountain switchbacks.

Power-hiking is a skill. Practice walking briskly uphill with purpose - this is often faster than trying to run steep grades and saves energy for when the terrain allows running.

Night Running

For races with night sections (most 100-milers), practice running in the dark. Your pace will slow, depth perception changes, and mental fatigue hits differently at 2am. Get comfortable with your headlamp and learn to trust your footing.

Strength Training

Ultra runners need durable bodies. Focus on single-leg exercises (lunges, step-ups, single-leg deadlifts), core stability, and hip strength. 2-3 strength sessions per week during base building, reduced to 1-2 during peak weeks.

Nutrition & Fueling Strategy

Nutrition is often called the "fourth discipline" of ultrarunning. You can be perfectly trained, but if you can't eat, you can't finish.

Calorie Requirements

Plan to consume 200-400 calories per hour during your ultra. You'll burn more than this, but your gut can only absorb so much. The goal is to slow the depletion, not match your burn rate.

Use our calories burned calculator to estimate your hourly burn rate, then plan to replace 30-50% of those calories.

Train Your Gut

Your stomach is trainable. Practice eating during long runs using the same foods you'll use on race day. Start with easily digestible carbs (gels, chews, sports drinks) and experiment with real food (PB&J, potatoes, pretzels) for longer efforts.

Many runners find that appetite decreases and food preferences change during long efforts. Sweet foods that taste great at mile 10 might be nauseating at mile 50. Have variety available.

Hydration & Electrolytes

Drink to thirst, but don't overdrink. Hyponatremia (low sodium from overdrinking) is more dangerous than dehydration in ultras. Take electrolytes, especially in hot conditions. Salt tablets, electrolyte drinks, or salty foods all work.

Gear Essentials

Ultra gear is about function and comfort over many hours. Here's what you'll need:

Mental Preparation

Ultramarathons are as much mental as physical. You will have low points - everyone does. The difference between finishers and DNFs is often mental fortitude.

Break It Into Segments

Don't think about running 100 miles. Think about running to the next aid station. Break the race into manageable chunks: aid station to aid station, sunrise to sunset, or any other milestone that works for you.

Mantras and Self-Talk

Develop mantras that resonate with you. "Relentless forward progress." "Pain is temporary, pride is forever." "This too shall pass." When your mind goes dark, having practiced phrases to redirect your thoughts can pull you through.

Embrace the Low Points

In every ultra, you will hit walls. Your legs will hurt. You'll question why you signed up. This is normal and expected. The magic of ultras is that low points pass. Eat something, drink something, walk for a bit - and suddenly you feel human again.

Crew and Pacer Strategies

For longer races, having crew (support at aid stations) and pacers (someone to run with you) can be game-changers. Pacers provide conversation, navigation help, and accountability. Crew can have fresh clothes, specific foods, and moral support ready.

Race Week & Race Day

Tapering

Cut volume by 40-50% in the final 1-2 weeks while maintaining some intensity. For a 100-miler, start tapering 2-3 weeks out. For a 50K, 10-14 days is sufficient. You should feel slightly restless and eager to run - that's the taper working.

Pre-Race Nutrition

Don't try anything new. Eat familiar foods. Carb-loading in the final 2-3 days can help, but don't overdo it to the point of GI distress. Stay hydrated but not overhydrated.

Pacing Strategy

Start slower than you think you should. This is the most common mistake in ultramarathons. If you feel great at mile 10, you're probably going too fast. The race doesn't start until the second half. Use a pace calculator to set conservative early splits.

Aid Station Efficiency

Time spent sitting at aid stations adds up. Know what you need, get it, and move on. Have a mental checklist: fill bottles, grab food, check blisters if needed, leave. Practice this in training.

Sample Training Weeks

50K Training (Peak Week)

100-Mile Training (Peak Week)

Frequently Asked Questions

Related Guides