The marathon can feel smooth until mile 18 to 20, then your legs turn heavy and your pace falls apart. That “wall” is often a fuel problem, not a toughness problem. If you start too fast or under-fuel early, it can show up fast and stick around.
This guide pulls from exercise physiology basics and real-world marathon pacing and fueling routines. It’s written to help beginner runners troubleshoot the most common wall triggers without guesswork.
You’ll learn how to spot the wall early, build training that improves fuel use, and pace the first half so you do not pay for it late. You’ll also get a simple race-day eating and drinking plan, plus a calm playbook if you still bonk. Ready to reach the finish line with a plan you can follow?
Hitting The Wall Explained
Hitting the wall is a physical and mental state when you have no energy left for running, and your body and mind force you to slow down or stop. At this point, your legs feel heavy and rigid, you struggle to find the reason to go on, and each subsequent step requires tremendous effort.
Let’s shed some light on the process behind the marathon wall and its reasons. The human body has two sources of energy:
- calories from food
- burning body fat.
The primary source of fuel in our bodies is food. Once this energy source is exhausted, the body starts to burn body fat to keep us moving. At this exact moment, hitting the bonk occurs.
So, what’s wrong with body fat? Mining energy from body fat is a slow and inefficient process that requires energy too. Hence, the whole body switches to energy-saving mode and slows you down.
Ok, why don’t we eat more calories while running? Under extreme load, our body directs energy to the legs where it’s required the most. At the same time, the digestive system is barely functioning and getting scares of energy. Loading the stomach to get a new portion of calories is a bad option because it requires energy and will take the calories dedicated to your legs. As a result, you’ll run slower with the weight in your stomach and feel nauseous.
Who is The Most Vulnerable to Hitting the Wall?
The two groups of runners that are most likely to hit the marathon wall are:
- First-time marathoners
- Ambitious amateurs that started too fast
First-time marathoners are rarely well-prepared for 26.2 miles. Profound changes should happen to the runner’s heart, muscles, and tissues to easily conquer it. Beginners usually have been hitting the wall all the second half of the marathon.
Ambitious amateurs overestimate their capabilities and struggle to allocate their effort efficiently. They run the first half or even 20 miles with a good time but hit the wall and fail dramatically on the last 6 miles or less. The amateur runners are usually well-prepared for a targeted marathon time in an ideal environment. Still, they didn’t discount the pace because of: severe wind, sun activity, rain, high humidity, altitude, harsh or soft terrain, and others. Although, in most cases, runners commit to the marathon goals they are not ready to execute yet.
When Hitting the Wall Usually Happens?
On average, our body accumulates 2000 calories from food before the race. During a marathon, the runners spend around 100 calories per mile. So, most runners report hitting the wall around the 20th mile or 2nd hour of running—depending on what happens first. Although, the exact number depends on the individual physical fitness, weather conditions, and relative effort.
How to Prepare for a Wall-Free Race in Advance?
To avoid hitting the wall, the preparation for a marathon should start at least three months before for experienced marathoners and 8-12 months for rookies. Here are four simple steps you should complete beforehand to prevent a runner’s wall.
Step 1. 125-155 mileage monthly
A good rule of thumb to finish a marathon without fighting with the marathon wall is making 30-35 miles a week. Adhering to this weekly mileage will develop your heart and blood system and prepare them for extreme loads, like a marathon race. To avoid hitting the wall, you need to make it not once but for 8-12 consecutive weeks before a race. Yes, with strong guts, you can make a marathon anyway, but the less your weekly mileage is—the more you’ll struggle with the runner’s wall.
Step 2. Long-distance runs every week
Regular long-distance runs trigger significant changes at the tissue level and gradually adapt our bodies to the growing demand for energy. Scientists have shown that 2-2.5 hour weekly runs will increase the energy capacity in our cells by two times. Athletes who practice long-distance running every week can jog twice longer distances without hitting the wall as untrained ones.
Step 3. Marathon tempo runs weekly
Miracles never happen in a marathon. Marathon time is the ultimate result of the preparation work done a year before. A good rule of thumb to avoid hitting the wall is running a marathon within a 3rd heart rate Zone (~140-160). To adapt your muscles and joints to the desired speed and respective load, do a 5-7 mile tempo run with the desired marathon pace once a week. You correctly pick the desired marathon pace if you complete it with an under-threshold pulse.
Step 4. A control 19-mile run before a marathon
You have a good chance to avoid hitting the wall if you can do 80% of the distance within a targeted time and safe hr-zones. So, make a control 19-20 miles run before the marathon to check if you are. Schedule this run one month before the race day, so your body has enough time to recover. Moreover, make this run maximum similar to the actual marathon race, try the nutrition gels you’ll have during the race, and schedule hydration, like on the actual marathon day. So, you’ll be sure your stomach will tolerate the amount of water and nutrition without any adverse effects.
How to Prevent Hitting the Wall on a Race day?
Your actions and decision on the day of the race primarily determine whether you will be bouncing the marathon wall or not. Here are four steps that help you prevent hitting the wall on a race day.
Step 1. Carb-rich dinner and breakfast
Good dinner and breakfast will help you accumulate enough calories in your body to prevent hitting the wall. Eating more calories or trying new food won’t help you avoid the marathon wall, but it can worsen. I repeat the wisdom from many runners that spoiled many races: NO TO ANY NEW FOOD YOU DIDN’T EAT USUALLY.
For the evening dinner before the race, runners worldwide make pasta parties. However, macaroni and cheese isn’t the only possible dish; it could be rice, potato, or other carb-rich food—non-spicy, low-fat, regular size dish.
It could be cereals, eggs, toast, fruit, tea, or coffee for breakfast. If that isn’t something you usually eat for breakfast, don’t experiment and eat your regular breakfast. Don’t eat much and finish your breakfast 2 hours before the race.
Step 2. Proper dressing
The temperature at the marathon finish line will be 10-20° higher than at the start. Moreover, your body will overheat during a race regardless of the weather outside. It will spend precious energy to cool down, dehydrate quicker, and increase the chances of hitting the wall. As a result, So, dress lighter than usual; you will be a little cold at the start, but OK during the race.
A sleeveless technical T-shirt and shorts is a usual marathon clothing for 55°F/13°С and above. If it’s colder outside, consider adding compression socks, a hat, cotton gloves, and an additional layer of clothes you can throw away during a race.
Step 3. Nutrition and water supply during a race
Every runner is dehydrated after a marathon always. Lack of water during a race leads to energy loss and brings you closer to the marathon wall. On the other hand, excess water makes running harder, flushes the minerals out, and can result in muscle spasms. So, a golden rule is to drink water at every aid station or every 2-3 miles. If you aren’t thirsty, make just a few sips. In case of scorching weather, drink more.
There must be a reasonable balance with the quantity of food you consume during the race. Too much fuel makes running more challenging. Lack of it fast tracks hitting the wall. Energy gels, bars, and chews are the most common types of nutrition during a marathon, as they are easy to digest and carry. Eat the first serving after the 6th mile or 1 hour of the run. Afterward, take a new dose every 3-4 miles or 30 minutes. Take your nutrition before the water stations—washing the fuel with water helps your stomach.
Be careful with the isotonic drinks and some carbohydrate gels distributed during the marathon. Test them beforehand on your long runs, or take your own. The digestive disorder is the least desired issue during a race.
Step 4. Staying in the safe heart rate zones
A golden rule of marathon heart rate is 80-90% of your maximal pulse. It varies depending on gender, age, and physical fitness, but it’s 150-170 bpm for most people. Moreover, in the first half, you should run under 160 bpm, and in the second part at 170 and lower.
If you start too quickly, you’ll run with a higher heart rate and soon burn all the stored energy. The lesser the intensity of your running, the lower energy you will consume, and the longer you will avoid hitting the wall.
Hitting the wall vs bonking: how to troubleshoot a late-race fade
Not every slowdown is “hitting the wall.” The late-marathon crash is often a mix of low fuel, rising effort, and a brain that wants you to protect yourself. Spot the pattern early, and you can often limit the damage.
Fuel-related bonking often starts with sudden hunger, shaky hands, chills, nausea, or a foggy head. You might also notice negative self-talk and trouble focusing. Overpacing looks different. You feel out of control early. Your breathing stays hard, and your form falls apart before you have taken much fuel. Heat and dehydration have their own tells. Your heart rate climbs at an easy pace. You may get a pounding head, a dry mouth, or trouble cooling down.
When you feel the slide beginning, try a simple ten-minute reset. First, back off to an easy jog or short walk for 60 to 90 seconds. Second, take carbs you tolerate (gel, chews, or sports drink). Chase it with a few sips of water. Many runners start around 30 to 60 grams of carbs per hour on long runs. Practice this in training, then adjust for your body and pace. Third, cool your system if you can. Grab ice, pour water on your head, and move to shade when possible.
If you feel dizzy, confused, or cannot run straight, stop and get help. Otherwise, build back gradually for a few minutes. Think “smooth and steady,” not “make it back all at once.”
What to Do if You Hit the Marathon Wall?
Regardless of how trained you are, you may still hit the wall if you did your best during the race. Therefore, don’t panic; here are a few tips to help you overcome the marathon wall.
Slow down or walk for a while
Before hitting the wall, your muscles accumulate fatigue and need a decreased load to recover—walking. Sometimes you can even feel if you run 50 feet more, you’ll catch a muscle spasm. Let yourself walk to the nearest tree or streetlight, and then try to run again. Start with a pace almost equal to walking, and increase your speed slowly.
Proceed with nutrition
Give your body a quick energy boost by consuming energy gels, bars, nuts, or fruit. Chew them thoroughly and drink some water to help your stomach. A cup of cola or isotonic drink will be precious too. Do not overload your digestive system.
Get along that you will finish anyway
Hitting the wall usually happens when you are about 5 miles from the finish line, and there is no shorter course. You have to get there at least to meet your friends or family, take your stuff from storage, eat something sweet, drink beer, lie down and relax. You can walk the remaining distance, but jogging will get you there faster.
Don’t stop—bargain with your body
You can run slowly or walk, but don’t stop moving, whatever it takes. Try to notice even slight relief and then increase your pace again. Higher speed is necessary not to set your PB but just to finish the race quicker. Check your pulse to ensure you’re running within a safe heart rate zone. If you feel the wall is coming back, slow down, keep a slow pace for another 5 minutes, and give a new try to speed up again. You never fail until you stop trying and bargaining with your body.
Focus on one step at a time
Hitting the wall is happening in our minds first, and you need to clean up there to get through. Avoid distractions and thoughts about nature around, other runners, and even stop listening to music. Concentrate only on your next step and put all your effort into that step. Eliminate useless activities and achieve maximum energy efficiency. After you’ve made the step, concentrate on the next one. Just one. Then the next one.
You just can overcome a marathon wall
More than one million people overcome bonking and complete their marathons yearly. It isn’t rocket science, after all. If you did your home task and prepared responsibly, you’ll be among those million marathon finishers.
Final Thoughts
Hitting the wall can happen to anyone, from a rookie to a seasoned runner. Proper nutrition and training can reduce the likelihood of facing the runner’s wall. Still, there are numerous factors beyond your control. While your physical fitness and nutrition are the cornerstones of a marathon wall, you should also pay attention to the mental aspects. Whatever it takes, don’t stop, eliminate distractions, and focus on one step in a row. Good luck!
FAQs on the marathon wall
What does “hitting the wall” feel like in a marathon?
Hitting the wall feels like you suddenly run out of usable energy and your pace drops. Your legs can feel heavy and stiff, and your mind may get negative or foggy. It often shows up as “I can’t hold this effort anymore” even if your lungs feel fine.
Is the marathon wall the same thing as bonking?
They are closely related, but not identical. Bonking is the energy crash that happens when your stored carbs (glycogen) run low. The marathon wall often includes that fuel problem plus mental strain and muscle fatigue.
Why do runners often hit the wall around mile 20?
Many runners report the wall around mile 20 because stored carbs can run low by then. Faster pacing, heat, wind, hills, and dehydration can make it happen earlier. A steadier pace and a practiced fueling plan can push it later or prevent it.
How should I pace early to avoid the wall later?
Start controlled, even if you feel fresh. Keep the first half at an effort you could hold for hours, not minutes. Avoid surges, weaving, and “making up time” early, that burns fuel fast.
How often should I take gels and drink water to help prevent the wall?
Most runners do best with small, regular fuel and fluids. Take your first gel around one hour in, then take another about every 30 minutes (or roughly every three to four miles), and sip water at most aid stations (or every two to three miles). If you can, take fuel a few minutes before water so it goes down easier.
What should I do right away if I feel the wall coming on mid-race?
Slow down immediately, and give yourself a short walk break if you need it. Take quick carbs (like a gel or chew) with water, then ease back into a jog and build speed gradually. A simple reset helps, for example: walk to the next aid station, then jog easy for a minute.
What training helps you avoid the wall on race day?
Higher weekly mileage, weekly long runs, and marathon-pace practice all help. Many runners do well building toward about 30 to 35 miles per week for 8 to 12 weeks, plus a weekly long run around 2 to 2.5 hours. A controlled 19 to 20 mile run about a month out is a good time to practice the exact gels and drinks you plan to use.
When is “hitting the wall” more than normal fatigue, and when should I stop?
Stop and get medical help if you have chest pain, fainting, severe confusion, trouble staying awake, or you cannot keep fluids down. Also stop if you have chills, severe headache, vomiting, or you feel dangerously overheated. Normal fatigue feels hard but steady, red-flag symptoms feel wrong or scary.
I completed my first 10K on a dare. In a year, I ran a half-marathon. Another year later, I finished a marathon race. Today I run 4 marathons a year and a half-marathon every week. I learned everything about running the hard way. So, I help runners achieve better results easier.
