Why runners hit the wall

Maybe you’ve heard of “the wall” or you’ve already experienced hitting it. Many runners live in fear of it interfering with their race.

Why runners hit the wall

What does it feel like?

Sometimes it’s your body that wants to give up, sometimes its your mind, sometimes it’s both.

Either your legs feel like jelly, your feet are made of lead and every fibre of your being seems to be screaming at you to stop running. Or your brain is foggy, you can’t remember why you’re doing this, you’re doubting your running abilities and you’re sure you can’t go on.

But it’s important to know that ultimately you can avoid it. The key to avoiding the wall is understanding what’s going on in your body, and preparing yourself for it through training and nutrition.

Understanding fuel sources

Your muscles are fuelled using a combination of fat and glycogen. The percentage of each type of fuel used at any particular time varies, however. The harder you are pushing yourself, the higher the percentage of fuel comes from glycogen. And when you run out of glycogen stores, “the body will rely on fat almost exclusively for energy, which is quite inefficient in untrained individuals, the resulting effect of which is reduction in the muscles ability to function normally and a feeling of quite extreme fatigue,” says sports nutritionist Glenn Kearney.

If your glycogen levels are low you will feel like you’re running through a vat of treacle. If your blood sugar level is low, your brain will be foggy and unmotivated, and you may even start hallucinating!

Carb loading

Carb loading before the race ensures maximum storage of glycogen in the muscles and liver. The average person on a normal diet can store around 1500 calories in the form of glycogen. However if you carb load effectively can increase this up to 3600 calories. Find all your need to know about carb loading in this article: the lowdown on carb loading.

Fuelling on the go

Take on carbohydrates during the race, in the form of gels, sports drinks, fruit, jelly babies, etc. Plan to do so at regular intervals, but if you feel the wall coming to get you, get some carbs down you as fast as you can.

Sports Nutritionist Emma Baraclough says, “You only have enough stored carbohydrate to last you for about 90 minutes of running, so you need to take in extra to avoid completely depleting your glycogen stores and hitting the wall. This is most likely to happen from mile 16-20, depending on how fast you run. Starting to take carbohydrate early into your run helps to preserve your glycogen stores and stave off early fatigue.”

Train right and your body will be prepared

If you include lower intensity long runs in your training programme you will be training your body to use stored fat as a fuel source and it will do so more readily on race day.

Practise fuelling with carbohydrate sources during your long runs. Nancy Clarke, nutritionist and author of Sports Nutrition Guidebook says, “What you eat for breakfast before your long run should provide enough calories to fuel the first hour of your run. After that, I generally recommend:

  • a 120 to 170-pound person should target 200 to 300 calories per hour.
  • a lighter person might want 100 to 200 calories per hour.
  • a heavier person should target 300 to 400 calories per hour.

“But how much fuel a runner should consume really depends on how much he or she can tolerate and the intensity of the exercise. Experiment to learn the right amount that works for your body and maintains your energy.”


There’s so much talk about gels and energy bars that you might forget how important it is to stay hydrated. When you lose water through sweat, your overall blood volume is reduced, meaning that there’s less blood available to carry oxygen to your muscles. Dehydration can have a strongly negative effect on performance. Good hydration is also needed for your body to be able to absorb carbs efficiently. You can find our tips on race day hydration here.

Nancy Clark advises marathon runners to “prevent dehydration and hypoglycemia (low blood sugar) by drinking 6 to 8 ounces of sports drink every 15 to 20 minutes, depending on the weather, your body size, your sweat rate, thirst, and pace. Because sports drinks contain carbohydrates (sugar), they can fuel both your muscles and your mind. They invest in greater stamina and endurance. If sports drinks upset your stomach, drink plain water and nibble on energy bars, hard candies, jellybeans, gels, chomps, or other carbs that you can tuck into a pocket.”

However it’s important not to drink too much as this can be extremely dangerous. Nancy says “Whatever you do, do not OVER-hydrate. If your stomach is sloshing, stop drinking!”

Fasted training

In training, try running without having eaten breakfast to prepare yourself for the sensation of your body running out of glycogen and having to burn fat.

Tips to help                               

Remove yourself mentally from the present, think of somewhere you love, imagine yourself there. Distract yourself with happy thoughts and you may well find that the wall is suddenly gone.

Visualise yourself crossing the finish line, surrounded by your friends showering you with glory and praise.

Lower the intensity

If you feel like you just can’t carry on, rather than succumbing and stopping dead in your tracks, take the intensity down a notch. You’ll find the body can adjust to a lower energy output and the feeling of hitting the wall will pass.

It can be very disconcerting to have trained hard and yet suddenly feel as if you cannot go on. However, if you can tell yourself that it’s just your body switching fuel sources, you can overcome the feeling of hitting that wall.

Join now for free!

Get fitter, stronger, faster with The Running Bug.

Trending now

  1. Strawberry and banana oat bars

  2. Easy banana protein shake

  3. 30 day core challenge

  4. 4 reasons gin is great for runners

You might also like


You must be signed in to view or add comments.

Sign in or Join


Oops, something went wrong.