What is an ultramarathon distance - and is the race right for you?

By Sarah Finley

Ultramarathons are anything above a standard marathon distance
Common ultra race distances are 50km, 100km, 50 miles and 100 miles, though some are longer
An ultra distance training plan should involve a mix of long runs and interval sessions
Hydration, diet and rest are important during ultramarathon training

If you’ve got the running bug after completing a marathon, you may be considering your next fitness goal. Ultramarathon races are popular as they challenge runners who want to go beyond a standard marathon distance of 26.2 miles.

But what is an ultramarathon distance? It's defined as anything longer than the standard marathon distance, and can range anywhere between 50 km to 100+ miles. The terrain of the course may also be different to a traditional marathon, with some that involve trail running or running over more complicated terrain, such as sand or gravel.

There are various ultramarathon events around the world to choose from, and a range of training plans available. An ultra distance can be a fantastic goal for runners of all abilities, though it’s important to properly train your body for the race with a variety of training runs, strength work, rest and good nutrition. Here’s everything you need to know about running an ultramarathon.

What is an ultramarathon distance?

Unlike the traditional marathon, ultramarathon distances can vary - so it’s best to pick one to suit your running ability. Common distances are 50km, 100km, 50 miles and 100 miles, though there are some races that are longer still.

Ultramarathons can also be based on time. Timed races range from eight to 48 hours - although again, there are some that are longer - with periods blocked out for sleep. Other ultramarathons are spaced out over a number of days, requiring you to complete a set distance each day.

How to train for an ultra marathon

It's recommended that you allow a four to six month time frame for your training plan. There are a number of plans readily available, such as this 50-mile ultra training plan from Runner's World or this 30-week plan from Women's Running. Your training plan should include a mix of long runs, shorter distance tempo runs, and cross training such as strength and conditioning.

Start with one or two runs a week, a longer base run at the weekend where you stay in heart rate zone 2 (or conversational pace) and a shorter interval focused session in the week. Then gently increase the base run time, but by no more than 10% every week.
Ultramarathon runner and head trainer, Chloe Trigg, at BLOK gym advises

She goes on to say that as you start to build your running base, you should add more of the shorter runs each week, anywhere from one to four. “The idea being that you increase time on feet and mileage over the week, rather than only doing one or two big runs each week,” Trigg adds.

Different types of training run

Long runs - A long run is designed to test your endurance (both physical and mental) and build up time on feet while running. Most training plans include one long run per week. The distance will depend on your running ability but should increase week-by-week by no more than 10%. The pace should be easy and relaxed. As the distance increases, it's important to start thinking about proper fuelling before, during and after your run.
Interval sessions - These sessions will improve your overall fitness levels, allowing you to run further and possibly quicker on your longer training runs. A typical interval training session is designed to be challenging and may include intervals of speed work or uphill running. Trigg advises you start with 6 x 400m sets, with two minutes of easy running in between each set. Once your body is used to this, “build the distances of the interval sessions, for example 6 x 800m or 4 x 1000m." Interval sessions can be completed on a treadmill or outdoors. An easy way to construct an outdoor session is to pick a landmark that is roughly 400m away - for example a lamppost or a tree - sprint to it, then turn around and easy jog back to your starting point. Repeat as many times as necessary.

How else should I prep for an ultramarathon?

Diet - Fats, such as avocados, nuts and oily fish, plus protein, such as chicken, tofu or eggs, are the best types of food to top up on during your training plan. Trigg explains why a higher fat diet is important: “Your body will use fat stores as its fuel source when training at a lower intensity, and as about 70% of your training will be in zone 2, your body will predominantly use fat for its energy source,” explains Trigg.
Hydration - Dehydration can hugely impact your performance. “If you are dehydrated by even the slightest, your exercise endurance can drop by almost half,” says Trigg. She goes on to say that if you’re dehydrated, it can also mess with your blood flow, core temperature and even how quickly you burn the calories you’ve eaten for the race.
Rest - “Ideally you want one full rest day and one active recovery day per week. A rest day should be a complete day off from training, so as to give your body the chance to repair and recover. Active recovery means light movement, ideally cross-training with a low impact activity such as 40 minutes of easy swimming, cycling or yoga, or low-impact bodyweight mobility exercises,” explains Trigg.

So, is the race right for you?

You may think that an ultramarathon is the preserve of athletes - or at the very least, marathon runners. But actually, they are a fantastic goal for runners of all abilities, including beginners. Some events don't even require you to run the whole distance and can be completed by walking and running. However if you are to embark on an ultra distance challenge, the most important thing is the preparation beforehand. Whatever your running ability, it's crucial that you give yourself enough time before the event to increase your overall fitness level, to build up time on your feet, to increase both your mental and physical stamina, and to ensure that you have sufficient rest and a proper nutrition plan to carry you through the race. Be sure to check out other things such as the entry fee, travel arrangements and sleeping arrangements (for longer events) before signing up.

Frequently asked questions

Is there a 100-mile ultramarathon?

UK-based 100 mile races include The “RaidLight” Arc of Attrition - a Cornish race, which takes place in January and is said to be one of England’s toughest foot races. Some of the most prestigious ultramarathons include Ultra Trail du Mont Blanc (UTMB) in the Alps and the Spartathlon, which is a 246-kilometre (153 mile) race in Greece - running from Athens to Sparta.

Is ultramarathon running good for your body?

All exercise is good for your physical and mental health - with one study by Dr. Martin Hoffman concluding that ultra running can be good for the immune system. The study looked at 1200 ultra runners and found that, on average, they took 2.2 sick days in a year compared to the national average of 3.7.

Trigg adds: “If done correctly and you give yourself plenty of time to build up to the distance, then ultramarathon running can be incredible for your body. It will vastly improve your cardiovascular fitness, strengthen muscles around your joints making them able to handle more impact, and improve your overall health.”

Who is the fastest ultramarathon runner?

Aleksandr Sorokin currently holds the record for the fastest 100-mile ultramarathon. He completed the event in a record time of 10 hours and 51 minutes in January 2022. Sorokin also holds the world record for the fastest 100km - he ran the endurance race in 6 hours, 5 minutes and 41 seconds.

Other fast ultramarathon runners include Ketema Negasa, who ran the fastest 50km in May 2021. He had an average pace of 3:15 per kilometre and completed the ultra marathon in 2 hours, 42 minutes and 7 seconds.

What is the longest ultramarathon?

The Self-Transcendence 3100 mile race, based in New York is the longest ultramarathon. Set over 52 days, competitors must run 59.62 miles (95.95 km) a day in order to complete the race - only 15 people have completed it since it started in 1996.

What are popular ultra marathon events?

Comrades Marathon, South Africa - First run in 1921, this is one of the world's oldest ultramarathon events and is set in the KwaZulu-Natal Province of South Africa. It takes runners from Durban to Pietermaritzburg (and vice versa) in a race that is approximately 55 miles long.

Spartathlon, Greece - This historic 153 mile ultramarathon is a tough race to complete. It mimics the journey taken by Pheidippides, an ancient Athenian long distance runner, who in 490 BC ran from Athens to Sparta before the Battle of Marathon to seek help in the war against the Persians. It's a timed race, with a cut off of 36 hours. In order to succeed, runners must reach 75 checkpoints within specific time intervals throughout the race.

Marathon des Sables, Morocco - Known as the toughest footrace in the world, this grueling challenge involves racing 156 miles through Southern Morocco across the Sahara Desert. It takes six days to complete, during which runners may experience peak temperatures of 50°C.

Tarawera TUM Mile Ultramarathon, New Zealand - This is an iconic trail race held in Rotorua, New Zealand’s birthplace of tourism. It has a 100 mile race distance with a scenic route that takes in lakes, waterfalls and lush New Zealand forestry. The varied terrain attracts some of the world's most elite trail runners.