“I really did it! Now I really am an ultrarunner.” Pride fills me as I write these words in my training journal. I had just completed a 50km training run – my longest long run to date and the last long run before my first ultramarathon.
I had started running again just 7 months prior, and this run was the ultimate test to see if I was ready to tackle the challenge of running 61 km over trails 6 weeks later.
Could I have finished the race without this long run? Very likely. Could I have achieved the 3rd place female finish I did? I’m not so sure.
While this long run wasn’t necessary from a physiological standpoint, it gave me confidence that I could cover the race distance and that I could do so within the cut-offs.
Looking back now, with several years of ultrarunning experience, I smile at my former self, who thought she needed to run 50km to prepare for a 61km race. While that long run served its purpose—primarily boosting my confidence—I now know that such lengthy training runs aren’t always necessary or optimal.
In fact, the relationship between training run length and race distance becomes increasingly complex as the distances get longer.
The question “How long should your longest long run be for an ultra?” is not as straightforward to answer as it is for shorter distances because ultramarathon training is more complex, and you need to consider more variables than only the distance covered or hours run.
The Unique Challenge of Ultramarathon Long Runs
In the world of the marathon, the running community accepts some general guidelines for the long run. For example, many plans suggest that your longest training run in a marathon prep should be around 32 km (75-80% of the race distance).
However, many coaches advocate capping the long run based on time – especially for slower runners. For example, Jack Daniels recommends that newbie marathoners don’t go longer than 2.5 hours, and Greg McMillan suggests a maximum length of 3 hours for most recreational runners.
In ultramarathon running, both approaches have their limits. The distance-based approach becomes increasingly impractical the longer the race distance. A 75-80km training run to prepare for a 100km race is excessive, and a 128km training run for a 160km race (the classic 100-mile distance) is bordering on insanity.
Applying a time cap isn’t as straightforward, either. While a 3-hour time cap may make sense in a race where the slowest participants usually finish in 5-6 hours, ultramarathons have unique challenges that (most) “typical” road marathons don’t have:
Vastly Different Time Domains
Ultramarathon race formats are extremely varied. (That’s one of the main reasons I am drawn to them). And that’s why the timeframe for participants to complete the events is not as narrow as in shorter distances.
For example, the difference between the female winner of the Western States Endurance Run (one of the most famous 100-mile races in the United States) and the last female finisher is a whopping 14 hours. The difference between the first and last male finishers was 15 hours. While the first male and female finishers needed 14 and 15 hours to finish, the last finishers arrived just before the 30-hour cut-off.
And these vastly different times on feet are just within the same race, where the distance is fixed. However, there are also timed races, such as 12h, 24h, 48h, and even 6 days, and fixed-distance races much longer than 100 miles. And then you have the backyard format, which is a last-person standing race. Unless you set yourself a cut-off beforehand, you won’t know just how much you will be running.
This immense variability in race formats and finishing times makes applying a simple formula like “cap your long runs at 3 hours” to ultra training impossible.
A fixed time cap that might work well for a runner targeting a sub-24-hour 100-miler would be woefully insufficient for someone preparing for a multi-day event.
The time spent on your feet during training needs to reflect the unique demands of your target race—and in ultrarunning, those demands can vary dramatically.
Terrain Variability
When you train for an ultramarathon, your long run needs to prepare you for the time you will spend on your feet on race day and how you spend this time. A 3-hour run on flat roads feels different than a 3-hour run on highly technical terrain, where you might need to climb over fallen trees or cover significant elevation gain.
Flat long runs repeatedly stress the same muscle groups in a similar pattern, which helps build the specific endurance needed for road ultras but leaves you unprepared for mountain ultras, where you need to be skilled in downhill running, have enough strength to climb steep uphills and be fast on the flats.
I have run flat, fast races (including 24-hour road) and mountainous trail races. While the basic training principles remain the same, I vary my training slightly to ensure I prepare specifically for the demands of the race.
For example, in 2024, I participated in a few mountain ultras. However, I didn’t have the luxury of living near the mountains, so I had to get creative. I prepared my body and mind for long climbs by utilizing the treadmill, performing hill sprints on local artificial hills, and strengthening my legs through kettlebell workouts. And I have done plenty of long runs that included running up and down the same hill for several hours. While these workouts weren’t fun, they prepared me well for the mountains.
In contrast, I prepare for flat and fast races in the first half of 2025. While I still do hill work, I also include fast long runs with minimal elevation gain (which isn’t very hard to achieve when living at sea level 😉).
Nutrition Complexity
Gastrointestinal distress is one of the main reasons ultrarunners drop out of races. Running for extremely long durations comes with unique nutritional challenges. So much so ultramarathons are often described as “eating contests with a little bit of running thrown in.”
While marathon nutrition can typically be practiced during shorter training runs, ultra-distance nutrition presents challenges that only emerge after many hours of continuous effort. When you run, your body diverts blood from your digestive system to your working muscles. That means your digestion isn’t working as well as it would if you were sedentary. And the longer you run, the more problematic this compromised digestion becomes.
While you can rely on your pre-race glycogen stores and a few gels to power you through shorter events, during an ultra, you face the challenge of taking in more calories for significantly longer while your digestion is compromised.
Running through the night (a necessity in many ultramarathons) adds another layer of difficulty. Naturally, many physiological processes change during the night, such as reduced enzyme production, a drop in core temperature, and hormonal changes, which can slow down gut motility.
That’s why long runs are crucial testing grounds for race-day nutrition.
Use them to experiment and learn which foods you can digest after many hours of continuous movement and which combinations of foods work well for you. Make sure you test a wide variety of food and have various options.
Fueling during an ultramarathon is crucial, and it can be the deciding factor if you need to death march the race until the end or if you will finish strong with a smile on your face.
Like many ultra runners, I struggled to fuel myself correctly in my first races. I always did my training runs first thing in the morning, without breakfast, and rarely took in fuel. Even when I extended my long runs, I barely took in any nutrition.
For the first 2 years, I raced all races severely under-fueled. While I still achieved great results with top ten and podium finishes, I knew I could perform better if I gave my body adequate calories during training and racing.
The following year, I tested my theory during a 24-hour race held on a motocross track. This was my first race that included a significant amount of elevation gain, and while the hills weren’t long, they were steep. I felt utterly unprepared and expected to hike a lot.
However, the continuous eating from the beginning (something I had never done before) gave me enough fuel to keep me moving well throughout the race. Surprisingly, I won the race and recovered much faster than I had from previous events.
My experience at that 24-hour race taught me an important lesson: long runs serve multiple purposes in ultra training, and sometimes we must prioritize one aspect over others.
While I had been using my long runs primarily for building physical endurance, I had neglected their crucial role as nutrition practice sessions.
The Multiple Purposes of Ultra Long Runs
The previous section highlights an important aspect to understand when you are planning your long runs. Long runs in a marathon prep serve primarily to build endurance and practice race pace, but long runs in an ultramarathon prep must accomplish several distinct goals. When you understand the primary goal for your long run, you can structure their length and intensity so that it makes the most sense for your training status, target race, and race goals. Let’s quickly look at the various components:
Physical Component
The physical component is what most people focus on when they think about long runs. And sure, long runs build the endurance needed to stay on your feet for extended periods, strengthen muscles and connective tissues, and train your endocrine system to handle prolonged stress.
If you’re relatively new to running – or ultrarunning – then the physical component will be the primary reason for extending your long run. Your body simply needs to get used to spending a lot of time on your feet.
Mental Component
When you’re reasonably fit and can move well for many hours, the mental component of training may become a focus point for your long runs. In ultrarunning, mental fatigue often becomes a bigger challenge than physical fatigue.
While a marathon might push you to your limits for a few hours, ultras require you to manage discomfort, make decisions, and stay focused for much longer periods. The monotony of climbing up a hill under the scorching sun or running a 1km lap hour after hour can quickly become overwhelming if you haven’t conditioned your mind to be able to withstand the mental agony.
And just like you can use your long runs to train your body to move continuously for many hours, you can use your long runs to train your mind.
If you tend to get bored quickly, practice staying with it by running without distracting yourself by chatting with others or wearing headphones.
No chatter with friends, no music, no podcasts, no audiobooks. Just you and your thoughts.
When I started running, I never used headphones because I wanted to condition my mind just as much as I wanted to condition my body. I knew I needed to learn how to stay focused and keep moving for much longer than I ever had before. I also wanted to develop mental strategies to help me push through on race day.
You also learn to distinguish between normal ultra discomfort and actual injury during long runs. This is a crucial skill to learn that requires experience and practice. Long training runs give you the opportunity to develop this skill in a controlled environment.
Nutritional Component
While I’ve already shared my journey to learning proper ultra nutrition, it’s worth emphasizing that some long runs should be specifically dedicated to nutrition practice.
These sessions might not feel great—they might go terribly wrong—but that’s exactly the point. You need to discover your limits and problems during training, not during your goal race.
This is especially important if you struggle with fueling (like I did) or have a sensitive stomach. During these nutrition-focused long runs, accept that your performance might suffer as you experiment with different fueling strategies. You might bonk spectacularly when trying a new combination of foods or discover that certain foods become intolerable after 6 hours of running. These “failures” are valuable learning experiences that inform your race-day strategy.
Remember that nutrition problems often compound during an ultra. What works for the first 4 hours might become problematic by hour 8. That’s why practicing your nutrition strategy during your longest training runs is crucial, even if they’re not as long as your goal race. The patterns you discover will help you develop a more robust race-day nutrition plan.
During those runs, keep all your wrappers and log the products you used, the weather, how fast or far you ran, and what time of day. Trust me; this info will come in handy when race day is approaching, and you’re ready to create your nutritional protocol for the race.
The better you understand your body’s reaction to various foods or sports nutrition products, the better you can plan your nutrition, and the higher your chances for a great race experience will be.
Different Approaches to Long Runs
Now that we understand the multiple purposes long runs serve in ultra training – physical adaptation, mental preparation, and nutrition practice – let’s look at how we can incorporate these elements into our training.
While marathon training typically follows a straightforward progression of gradually increasing long run distance, ultrarunning allows for (and often requires) more creative approaches.
Here’s how I currently approach long runs, mixing different strategies depending on my target race:
Here’s how I currently approach long runs, mixing different strategies depending on my target race:
Back-to-Back Long Runs
This approach becomes particularly relevant when I train for events that are 100 miles or longer or for timed events that are 24 hours or longer. Instead of doing one extremely long run, you do two moderately long runs on consecutive days. This teaches your body to run on tired legs while reducing the recovery time needed compared to a very long effort.
For example, running 30km on Saturday followed by 25km on Sunday can provide similar benefits to a single 45km run, but with less risk of injury and faster recovery.
You can also extend this to a 3-day back-to-back-to-back training block. I will utilize a few 3-day back-to-back-to-back long runs in my build-up to the 24-hour road German Championships in June this year.
Training Races
Using shorter ultras as training runs for longer goal races has become a valuable strategy for many ultrarunners. I, too, incorporated several shorter races into my training plan.
These events provide the perfect opportunity to practice race-day logistics, test nutrition strategies, and build confidence – all while having the support of aid stations and other runners.
There’s an important caveat, though. Training races can be detrimental to your success if you place them too close to your race or race them too hard. In either scenario, you won’t recover quickly enough to achieve your best performance during your goal event.
As I had to painfully learn in 2024, training races can lead to injury, which may put your start at your goal event at risk. Of course, the chance of injury is always there when you train for ultramarathons. However, you must carefully weigh the pros and cons of putting yourself in a race situation outside any goal events.
The experience from last year’s season, where a hard fall in a “training race” prevented me from ultimately starting at my main event, taught me not to see any race as pure training anymore but to carefully select my races, taper accordingly, and give every race my best.
Fast-Finish Long Runs
This is my favorite type of long run. Start these long runs faster than you would run your ultra, and then speed up and run the second half even faster than the first. This teaches your body to push when tired.
This approach helps develop the mental strength needed for ultras as you learn to increase effort when you’re already fatigued.
I believe that including these types of long runs regularly in my training is one of the main reasons I routinely gain places in the second half of races and that I have been able to finish strong in most of them. I taught my body and mind that I always have a second gear no matter how tired I think I am.
Specific Race Preparation
Sometimes, long runs need to mimic specific race conditions. At the time of this writing, I’m preparing for a 24-hour race in June, so I deliberately do my long runs as laps around my local park. While mentally challenging, this specific preparation is crucial—the monotony of training laps helps condition my mind for the repetitive nature of the race. However, I also make sure not to do those every week to keep the joy of running alive.
Why Single Long Runs Aren’t Everything
If you have made it this far in the article, I hope you understand why ultrarunning presents unique challenges that can’t be addressed simply by running longer and longer training runs. While marathon training might benefit from progressively longer runs that approach race distance, ultra training requires a more nuanced approach.
That’s why it is almost impossible to prescribe a certain distance or duration for your longest long run during an ultramarathon build-up.
The multiple purposes we’ve discussed – physical adaptation, mental preparation, and nutrition practice – are often better served through various training approaches rather than single epic efforts. For example, back-to-back runs can build endurance while practicing running on tired legs, fast-finish long runs develop mental toughness while improving running economy, and training races offer opportunities to test nutrition strategies in a supported environment.
This variety in training approaches, combined with the sheer length of ultra events, means that no single long run can fully prepare you for race day.
Instead, success in ultrarunning comes from the cumulative effect of consistent training, where each long run serves a specific purpose in your overall preparation.
How To Plan Your Long Runs for Ultramarathon Success
Just like I didn’t give specific duration recommendations for your longest long run, I didn’t include specific long-run workouts in this article (like in the speed development for ultras article).
Why? I wanted to help you understand the complex role of long runs in ultra training.
Understanding their various purposes—physical conditioning, mental preparation, and nutrition practice—can help you make more informed decisions about your training.
Consider your current training status: Are you new to ultras and must focus on building time on your feet? Are you an experienced runner who needs to work on mental fortitude for a challenging mountain race? Or perhaps you’re like I was, achieving decent results but knowing you could do better if you figured out your nutrition strategy?
Your long runs should reflect your current needs and limitations while preparing you for your specific race challenges. There’s no one-size-fits-all answer to “How long should my long run be?” Instead, there are thoughtful questions to ask yourself:
- What is the main purpose of this particular long run?
- How does it fit into my overall training plan?
- What specific race-day challenges am I preparing for?
- How much recovery will I need, and how will that affect my other training?
Armed with this framework and these questions, you can design long runs that serve your individual needs rather than following arbitrary guidelines. After all, that makes ultrarunning special – the freedom to find your own path to the finish line.
Note: This is part V of the Ultrarunning for Beginners series. The previous articles in this series can be found here:
Part I: So You Want to Run an Ultra-a Guide to Getting Started
Part II: Building Your Ultra-Training Foundation: From Plan to Practice
Part III: Beyond Easy Miles: Understanding Different Types of Training Runs
Part IV: Understanding Easy Runs for Ultra Distances: A Scientific and Practical Guide to Building Your Ultra Engine
Part V: The Science of Speed in Ultrarunning: From VO2max to Race Day Performance