Why You Don’t Need a 35 km Long Run Before Your Marathon

Almost every marathon training cycle I see the same question from athletes in Athletica:

"Why don't we run 35 km before the marathon?"

It's a fair question. If the race is 42.2 km, it seems logical to run close to that distance in training. Shouldn't we practice what we're about to do?

But over the years as an athlete, coach, and someone educated in the Norwegian endurance training tradition, I've learned that a good marathon preparation isn't about doing the longest run possible. In fact, very long training runs often do more harm than good.

What really matters is building the durability, physiology, and pacing discipline that allow you to run well when it matters most - on race day.

"The goal of training is to arrive at the start line ready to race — not already half-exhausted from it."

The elite comparison trap

Here's something I wish more every day runners understood. When you read about elite marathoners doing 35 km long runs, there's a crucial number missing from that story: how long it actually takes them.

A runner targeting a 3-hour marathon will do that 35 km training run at roughly 4:17 min per kilometre: a comfortable, controlled training pace for them. Someone aiming to break 4 hours covers the same distance at around 5:34 min per kilometre. That's a very different experience on paper. But look at what it means in real time on your feet:

Sub-3 hr marathoner: 2 hr 30min at 4:17min/km pace

Sub-4hr marathoner: 3 hr 15 min at 5:34 min/km pace

That’s a difference of 45 mins. Not 45 extra minutes of the same stress, but 45 extra minutes at the tail end of a run, when your energy stores are depleted, your form is breaking down, and your joints are absorbing the cumulative load of every kilometre before it.

Elites have built up to 35 km long runs over many years of high-volume training. Their bodies tolerate it. Copying the distance without considering the time on feet is like copying a professional chef's recipe but cooking it at the wrong temperature. The number looks the same. The result is completely different.

This is why I don't like to prescribe long runs by distance alone. Time on feet is the real variable that matters, and for most age group runners, 2.5 to 3 hours is where the stimulus becomes an unproductive risk.

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What happens when you run too far

Let's talk about what happens in your body when you push beyond about 28–30 km in a training run, which depending on your speed could take 2.5 hrs as an age-grouper.

Around the 2.5–3 hour mark, most runners, especially ones that are not fat-adapted, deplete a significant portion of their glycogen, the stored carbohydrate your muscles use as fuel. When those stores run low, your pace slows, your form breaks down, and fatigue sets in.

Running through that state doesn't make you tougher. It teaches your body to move inefficiently under duress, and it creates a recovery debt that can take 10–14 days to fully pay off. Do that too close to race day and you haven't peaked. You have effectively dug yourself a hole.

A very long training run also carries real injury and illness risk. Tendons, joints, and connective tissue take far longer to recover than cardiovascular fitness does. Many times I’ve coached an athlete who wants to do The Long Run and pushing it to 35 km - only to have to deal with lingering fatigue and cold the next weeks before the marathon.

What was supposed to be a long run to build confidence turned out to be a mental battle on race day: did I train enough? Will this cold affect me today?

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What your long run is actually for

The long run has a specific job: to build aerobic endurance, practice fueling, and build confidence. All three of those goals are achieved well within the 28–32 km range, and for most athletes, somewhere between 26 and 32 km is the sweet spot, depending on your experience and how your training block has gone.

What Your Long Run is Actually Training

Aerobic efficiency: teaching your body to use carbs and fat as fuel at marathon pace.

Fueling habits: practicing when to take in fuel, how much to drink, what your stomach tolerates.

Mental durability: getting comfortable with sustained discomfort over time. Practice your mantras!

Pacing discipline: learning what your marathon effort actually feels like in your legs.

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You can't build fitness without building recovery

This is where I think North American running culture gets something fundamentally backwards. I say this with love, because I've lived and coached on both sides of the Atlantic.

Fitness isn't just the load you apply to your body. It's the adaptation that happens when you recover from that load. Those two things are inseparable.

Apply load + recover = adapt.

Remove either half of that equation and the whole system breaks down.

I write about this tension regularly in my Substack, Nordic Sisu: the gap between knowing what the body needs and actually giving it permission to rest. It's one of the most common struggles I see in athletes, and if I'm honest, one I've had to learn from personally too.

"Adding more exercise while neglecting recovery is like trying to build a house starting from the ceiling down. It doesn't matter how much material you have - the structure has no foundation to stand on."

When athletes come to me with a nagging injury they can't shake, or a cold that keeps coming back, or a creeping fatigue they can't explain, my first question isn't about their workouts. It's about their recovery. Almost always, the load and the recovery are badly mismatched.

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What Norwegians understand about movement and we don't

The Norwegian approach to endurance isn't just about how athletes train. It's about how an entire culture moves through daily life.

In Norway, low-intensity movement is woven into the fabric of everyday life. People bike to work, walk to the shops, ski, hike in the mountains. This isn't structured training: it's just how life is organized. Children play outside after school. Adults take movement breaks that aren't framed as exercise at all.

The lifestyle that is essentially building on frequent movement breaks, is what we are trying to accomplish with Athletica. The result is that Norwegian athletes arrive at their formal training sessions sitting on top of an enormous aerobic base that has been built quietly, over years of incidental movement.

“In North America, most people sit for ten hours and then go to the gym for one. In Norway, people commute and then train on top of that. When North American athletes feel like they're falling behind, the instinct is to add more intensity. But intensity isn't the gap, the low-intensity base is the gap. You can't shortcut your way to an aerobic foundation that took years of daily movement snacks to build. Adding harder sessions on top of a missing base doesn't accelerate progress. It just increases injury risk.”

Low-intensity base means you are not afraid of zone 1. It’s not “junk miles”, it’s a true low-intensity effort where the heart rate sits comfortably anywhere between 55 to 72 % of maximal heart rate.

Someone with HRmax sitting around 185, the effective exercise intensity could be 101 - 133. Most people will complain how slow they have to go at this effort.

This is where you can hold a full conversation without straining, and is not just a warm-up or a recovery day filler. It is the foundation everything else is built on. And most age-group runners spend almost no time there, rushing through easy paces to get to the "real" training.

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Recovery is not a rest day. It's an active practice.

Here's a reframe that has changed my training thanks to my coach Professor Paul Laursen. I’ve paid it forward with my own athletes, and it has changed how many of my athletes think about their week: recovery isn't the absence of training. It's a different kind of training: one your body desperately needs to absorb the work you've given it.

That means Zone 1 movement absolutely counts. A 30-minute walk, a gentle bike ride, light yoga. These are not cutting corners. They are doing exactly what your aerobic system needs: gentle circulation, reduced stress hormones, active tissue repair without adding new load.

Beyond movement, there are recovery practices worth scheduling with the same seriousness as a tempo run. The body doesn't distinguish between sources of stress. A hard week at the office draws from the same recovery pool as a hard interval session. Everything counts.

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Nature time

Even 20 minutes in green spaces measurably lowers cortisol and calms the nervous system

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Yoga

Restores range of motion and activates the parasympathetic nervous system after hard efforts

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Sensory deprivation

Float tanks reduce muscle tension and support deep nervous system recovery between sessions

For someone born and raised in the deep Finnish forests, 20 mins in the forest still calms me down. These aren't luxuries for athletes with extra time. They are tools for athletes who want their training to actually work. Living in big city, my nervous system craves extra effort to bring it down, and so I do Sensory Deprivation tank once a month.

Once an athlete learns to pay similar attention to their recovery as they do with their hard training, it may come as a surprise how good they feel, and how much better their performance gets.

It certainly surprised me when I started working with Dr. Laursen after digging myself into an overtraining hole. After six months of recovery, my performance was way better than I ever expected. Now I understand why: my body needed time to reset, recover and absorb the training that took me over the edge.

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The Norwegian principle: quality over distance

The Norwegian endurance training model, which has produced some of the world's best endurance athletes, places strong emphasis on training smart rather than training hard for its own sake. The principle is simple: do frequent work that produces adaptation, recover fully, and repeat.

Best adaptations happen when the stimulus is repeated frequently, and that’s how we schedule runs at Athletica. Building yourself up to be able to run frequently has time and again shown the best adaptations with our most successful runners.

Every session has a purpose. Your easy runs are genuinely easy. Your quality sessions are specific to your race goals. You’re not suffering just to suffer and feel like you can take on anybody at a dark alley. Yes, occasionally you play with your limits, but then you pull it all back and let recovery trigger adaptation. And your long runs may take you over the mountains, or hills over the trails that are soft and gentle on your joints.

When we build marathon plans at Athletica, we apply this logic directly. The long run builds to a peak: usually in the range of 28–32 km, and then we taper.

Sometimes those runs are not in your schedule before few weeks ahead because the plan always adapts and only gives you those long runs if you’ve build a big base. Not because we don't believe in you. Because we want you sharp on race day, not tired.

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What actually gets you from 32 km to 42.2 km

The last 10 km of a marathon are not run on training miles. They're run on everything else you've built. Foundation built on a consistent volume of easy aerobic work for weeks. Strength to run a marathon built on race specific tempo pace. And executing the race with discipline starting smart, finishing strong.

Runners who blow up at kilometre 30 almost never do so because they didn't run far enough in training. They blow up because they went out too fast, didn't fuel properly, or arrived at race day already carrying fatigue. All of those are things you can control and none of them require a 35 km training run to fix.

Start conservatively. Finish strong.

Pacing discipline is the most underrated skill in marathon running. The difference between a runner who hits the wall and one who runs the second half almost as fast as the first is usually not fitness - it's judgment in the first 20 km.

When you practice long runs at a controlled, honest effort, not racing them, not pushing just because you feel good: you're ingraining that judgment. You're learning what sustainable actually feels like. That's the skill that carries you through kilometre 35, 38, 40.

"The runner who finishes well didn't save their best for the last 10 km by accident. They made a decision in the first 10."

So the next time you look at your training plan and wonder why there's no 35 km run - remember: we're not trying to simulate the race. We're trying to make sure you're ready to run it well. That's a different goal. And it leads to a better result.

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NORDIC SISU

The idea of enduring well: not just pushing through, but knowing when to hold back is something I explore deeply in my Substack Nordic Sisu. It's about what the Nordic tradition can teach all of us about strength, gentle grit, patience, and the kind of resilience that lasts a lifetime, not just to the finish line.