Two trail runners in woods with the sun shining through the trees

How long is an Ultra Marathon?

An ultramarathon is any foot race longer than the traditional marathon length of 42.195 kilometers or 26.2 miles. There isn’t a fixed length for an ultramarathon, they can range from just over the standard marathon distance to hundreds of miles.

What distances are ultra marathon races then?

Some of the most common distances for ultramarathons include 50 kilometers, 50 miles, 100 kilometers, and 100 miles. There are also timed events, such as 24-hour races, where the objective is to cover the greatest distance within the set time. Another form of ultra event is the multi-day race, which can extend up to six days or more.

How is an ultra marathon different to a road marathon?

Each ultramarathon is unique, with variations in terrain, altitude, weather conditions, and whether they take place on roads, trails, or a mix of both. These factors all contribute to the challenge of the race, beyond just the distance.

Running an ultra, such as a 50km race, is a different beast than running a marathon. While they both demand a high level of endurance and mental toughness, there are several key differences between the two in terms of training, nutrition, pacing, and mentality.

Ultra marathon training volume.

Training volume and intensity can differ significantly when preparing for an ultramarathon compared to a marathon, largely due to the increased distance and time spent on your feet in ultramarathons.

The overall weekly mileage is typically higher to build even greater endurance. However, the focus tends to shift from speed work (like tempo runs and intervals commonly found in marathon programs) to longer, slower runs designed to condition your body to be on its feet for extended periods.

As renowned running coach Hal Koerner writes in his Field Guide to Ultrarunning, “how much distance you cover each week–is a primary consideration when training for an ultra.” However, Koerner also notes that it’s not just about stacking on miles mindlessly. Instead, the focus shifts to back-to-back long runs, which simulate the fatigue of race day without the need to do a full race distance in training.

Ultra marathon training intensity

In marathon training, a significant emphasis is placed on running at or near your race pace. The goal is to improve your lactate threshold, or the point at which lactic acid begins to accumulate in your muscles, and to increase your body’s efficiency at burning glycogen as fuel. As such, marathon training often includes speed work, such as interval training and tempo runs, in addition to long runs. The idea is to help you sustain a relatively fast pace over the entire 26.2 miles.

On the other hand, in ultramarathon training, the focus shifts more towards endurance and time on your feet. The goal is to condition your body (and mind) to handle the fatigue that comes with running for many hours, often over challenging terrain.

Speed work is typically less of a focus; instead, training often involves slower, longer runs, back-to-back long runs, and running on tired legs. It’s not uncommon for ultrarunners to spend several hours on their long training runs, even if the pace is relatively slow.

The rationale behind this approach is that ultramarathons are run at a slower pace than marathons, and the ability to maintain a steady, moderate pace over an extended period becomes more critical than the ability to run quickly.

That said, each individual is different, and training should be personalized to fit your specific strengths, weaknesses, and goals.

Some ultrarunners may still benefit from incorporating speed work into their training, especially if they are focusing on shorter ultras (like a 50K), or if they have a strong endurance base but lack speed.

Also, while high-volume, low-intensity training is generally considered safe, any dramatic increase in training volume or intensity comes with a risk of overuse injuries, so it’s crucial to increase your training load gradually and allow for adequate recovery. Consider consulting with a running coach or other fitness professional when creating a training plan for an event as demanding as an ultramarathon.

How to fuel for an ultra

Marathon Fueling

Carb-Loading: A few days before the marathon, runners usually increase their carbohydrate intake to maximize glycogen storage, providing a readily available energy source during the race.

During the Race: During the marathon, runners usually consume easy-to-digest high-carb, low-fiber foods or specially designed products like energy gels, chews, or sports drinks. This is done every 45 minutes to an hour.

Hydration: Runners generally aim to replace fluids lost to sweat by drinking periodically during the race. Electrolyte replacement can also be necessary, often achieved through sports drinks.

Ultramarathon Fueling

Carb-Loading: Similar to marathon preparation, ultrarunners often carb-load before a race to maximize glycogen stores.

During the Race: Given the longer duration of ultramarathons, runners need to consume a steady stream of calories, often including a balance of carbohydrates, protein, and even fats. The race pace in ultramarathons tends to be slower, and the duration is longer, so the stomach can often handle more substantial foods. Runners may consume sandwiches, wraps, fruits, potatoes, nuts, or energy bars, in addition to energy gels or chews. Infact aid stations and the food provided at events can become a very hot topic of conversation and reason for a race to be highly recommended!

Hydration and Electrolytes: Due to the longer duration of the race, maintaining hydration and electrolyte balance becomes even more critical in an ultramarathon. Runners must drink fluids regularly and may need to consume electrolyte capsules or salty foods to replace sodium lost through sweat.

Training the Gut: Ultrarunners often need to ‘train their gut’ to handle food intake during long runs. Three tips for training your gut include the following.

Practice During Training Runs:

Use your long runs as an opportunity to practice your fueling strategy. Try eating and drinking the same foods and fluids you plan to consume during the race. This practice helps your body become accustomed to digesting and utilizing this fuel while running. Be sure to try different types of foods and nutritional products to see what sits best in your stomach and gives you the most energy.

Mimic Race Conditions:

Try to mimic race conditions as closely as possible during your training. This includes the timing of your meals, the type and amount of food you eat, and when you eat during the run. If possible, also match the intensity and duration of the race. The more closely your training mimics the race, the more effectively you’re training your gut.

Gradually Increase Intake:

Just like you would gradually increase your mileage to avoid injuries, it’s important to slowly increase your food and fluid intake during runs to give your digestive system time to adjust. Start by consuming small amounts of food and drink during a run, then gradually increase the amount as your tolerance improves.

Final point: It’s essential to listen to your body and adjust your strategy based on how your body responds.

Want to mske sure your race day nutrition is not a last minute panic, then read this.

Pacing an ultra marathon.

The pacing strategy for a marathon and an ultramarathon are markedly different due to the difference in race distance, terrain, and the increased need for energy conservation in ultramarathons.

Marathon Pacing:

In a marathon, the primary goal is usually to maintain a steady pace as close as possible to your goal pace throughout the race. A popular strategy is the even or negative split approach, which involves running the second half of the race at the same pace or slightly faster than the first half.

Proper pacing in a marathon is critical because going out too fast can lead to hitting “the wall,” where the body runs out of glycogen stores, leading to a significant drop in pace and increased fatigue.

Ultramarathon Pacing:

In an ultramarathon, pacing strategy is less about maintaining a fast, steady pace and more about energy conservation and management. The aim is to prevent fatigue for as long as possible and finish the race strong.

Start Slow:

The adrenaline and excitement at the start of any race can tempt you into running faster than you should, but doing so can lead to premature fatigue. Begin at a comfortable, easy pace, even if it feels too slow. The mantra “Start slow, then slow down” is popular in ultrarunning for a reason.

Manage Effort, Not Pace:

Unlike shorter races where you might aim to maintain a specific pace, in an ultramarathon it’s often more useful to manage your effort. Pay attention to your breathing, heart rate, and perceived exertion, and adjust your pace accordingly. Effort-based pacing is especially useful in races with varied terrain or elevation changes.

Walk the Hills:

Many ultrarunners adopt a strategy of walking the uphills and running the flats and downhills. Walking uphill can help conserve energy and give your running muscles a brief break. Just make sure to practice power-hiking during your training, as it’s more strenuous than casual walking.

Know the Course:

Familiarize yourself with the race course and plan your pacing strategy around it. Know where the major climbs, technical sections, and aid stations are. This can help you manage your effort more effectively throughout the race.

Stay Flexible:

Be ready to adjust your pacing strategy on the fly. How you feel, the weather, trail conditions, and many other factors can vary on race day. Remember, in ultrarunning, it’s often about resilience and adaptability more than sticking rigidly to a pre-set plan.

The ultra vs marathon mindset challenges

Running a marathon and an ultramarathon can both be mentally challenging, but the nature of the challenges can differ significantly. Here are some mental differences between running a marathon and an ultramarathon:


Speed and Sustained Effort: A marathon often involves running at or near your threshold pace for a sustained period. The mental challenge lies in maintaining focus and a high level of effort for several hours while dealing with fatigue, muscle pain, and the desire to slow down.

The Wall:

Marathon runners often talk about hitting “the wall,” typically around mile 20, where physical fatigue can translate into mental exhaustion. Pushing through this barrier requires mental strength and resilience.

Pacing and Split Times:

There can be a lot of mental pressure to stick to a specific pace or meet certain split times in a marathon, especially if you have a specific finish time goal. This can require significant focus and mental discipline.


Endurance and Patience:

Ultramarathons are more about endurance than speed. One of the key mental challenges can be dealing with the monotony and remaining patient, knowing that you’ll be on your feet for many hours, or even multiple days.

Low Points:

Ultrarunners may experience low points where they may feel extreme fatigue, sleep deprivation, or doubt their ability to finish. Overcoming these lows and maintaining a positive mindset is a significant mental challenge.


During an ultramarathon, runners often have to deal with unexpected issues like getting lost, suffering from blisters or other minor injuries, or having stomach problems. Being able to stay calm and solve these problems on the fly is crucial.

Terrain and Night Running:

Ultramarathons often involve challenging terrain, and in some cases, night running. Navigating this terrain or running in the dark can be mentally demanding.


In many ultramarathons, especially trail or mountain ultras, runners need to be more self-sufficient. There may be long stretches between aid stations, and runners need to be prepared to handle any issues that arise on their own.

Ultimately, the mental challenges of running a marathon or an ultramarathon can be as demanding, if not more so, than the physical challenges. Mental training, including techniques like visualization, goal setting, and mindfulness, can be hugely beneficial in preparing for these events.

Note: We aim to produce content that answers questions that our community members ask.  This blog was written after being asked the following question by Nicola. Click the image below to see the original tweet and community member responses.

Marathon vs Ultra marathon training question on a tweet from a ukrunchat community member