What is 'hitting the wall' during a marathon and how can you avoid it?
Get your coping mechanism in gear and you can scale the wall with confidence.
By Runner's World
ADRIAN DENNISGetty Images
What does it mean to 'hit the wall' during a marathon? The Americans call it 'bonking', and by any name it's a pretty awful experience. When you hit the wall, it feels like you have run face-first into a stack of bricks. Your legs start feeling like concrete posts, every step is a triumph of will and you seriously doubt that the race actually has a finish line.
Why do some runners 'hit the wall'?
In general, hitting the wall refers to depleting your stored glycogen and the feelings of fatigue and negativity that typically accompany it. Glycogen is carbohydrate that is stored in our muscles and liver for energy. It is the easiest and most readily available fuel source to burn when exercising, so the body prefers it. When you run low on glycogen, even your brain wants to shut down activity as a preservation method, which leads to the negative thinking that comes along with hitting the wall.
Noted exercise physiologist Dr Tim Noakes agrees that runners feel the wall physically, but he doesn't consider it a purely physical phenomenon. The brain, Noakes believes, tells the body it's time to hit the wall whenever it feels the body has gone too far, too fast. When the brain determines you have reached what it considers your breaking point, it increases levels of the chemical serotonin. This reduces neural control to recruit muscle fibres, which, in turn, triggers the sensation of extreme fatigue. Although a voice may whisper in your ear that you've given all you have to give, Noakes says in reality you can dig deeper and give more.
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How can you avoid 'hitting the wall' during a marathon?
It's important to note that you burn a blend of stored carbohydrate and fat for fuel all of the time. However, the ratio of these two fuels changes with the intensity of the activity. For example, during a speed workout you will use a higher percentage of glycogen in your fuel blend. On a long slow run, you would burn a higher percentage of fat and a lower percentage of carbohydrate.
If you do the math, it's easy to see why many runners hit the wall around the 18- or 20-mile mark. Our bodies store about 1,800 to 2,000 calories worth of glycogen in our muscles and liver. On average, we use about 100 calories per mile when running, depending upon run pace and body mass.
However, proper training for marathon mileage gives your body and mind time to adapt to these rigours. Since you don't use purely carbohydrate as fuel, you have the ability to continue running by accessing fat stores.
The energy issue then, is really about reaching for those fuel sources. In order to utilise your fat stores, you must have some carbohydrate present to facilitate this metabolic pathway. When you deplete your glycogen stores, it becomes difficult to access fat as a fuel source because burning fat for energy is a more complex process. Long runs help train your body to utilise the fat metabolic pathway more efficiently.
During training you should also experiment with taking nutrition on longer runs for a quick carbohydrate source. By the time you build up to 20 mile runs, you should have a pretty good idea about how much fuel you need to sustain yourself for this distance.
Hitting the wall is not something that needs to be feared, dreaded or avoided (unless it's race day, of course). The old adage of "if you don't use it, you lose it" can be applied here.
Training is more than just logging the miles. It is a total body process, and by the end of it you will be transformed into a runner that is prepared and ready to meet all the demands of the marathon. Between stored glycogen and stored fat, you actually have the ability to run many, many miles.
How to cope if you do 'hit the wall' during a marathon
1. Distract yourself
Investigations into which brain strategies work best for non-elite runners have found external disassociation (focusing on scenery, crowds, things not directly tied to the race) appears to be the most effective wall-avoidance strategy and results in a later onset of fatigue. A cheering crowd, a spectator's sign or a band playing in the distance may be just enough to distract your brain from the punishing bodily sensations of running, but without causing you to lose focus on pace and water stops.
2. Mentally hurdle it:
Positive self-talk and visualisation play a huge part in avoiding the wall. Before the race begins, do some visualisation exercises in which you hit the wall and picture yourself dealing with it effectively. If you believe you will dominate the wall, you are more likely to make those beliefs a reality.
3. Face reality
If you do hit the wall, sip some sports drink to get carbs into your system, but don't overdo it. And it's best if you have a running partner who can help encourage you through the worst and run with you to the finish. Please remember, however, that hitting the wall can affect your ability to think. I have seen plenty of runners disorientated and slurring their words, then being taken into a medical tent for treatment. I feel concern when I see them wobbling on the course, trying to make it to the finish. There is a point of no return that you need to accept. Going beyond that can be dangerous. If it's not your day, it's not your day. There will be others.
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