Are you scared of hitting the dreaded wall? Our fears are usually far worse than reality. Instead, embrace your fear by turning it into curiosity. If you really want to run a marathon, jump into training with both feet.
Not everyone who runs a marathon will “hit the wall.” There are many factors that contribute to this phenomenon, and some are within your control while some may not be. Researchers suspect it is likely that genetics plays some role in this, and your daily diet may also be a factor.
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.
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 rigors. 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.