The Wall is the term used when runners reach a point where they have depleted their glycogen (which is converted from carbohydrates). It is kind of like running “on empty”. When glycogen is depleted, your body begins to depend on fat as the source for energy. This creates a transition within your body that initially causes you to have very little energy.
How to avoid the wall is the common question. Proper training and nutrition (carb loading) can help to minimize your chances of reaching this point. The amount of time you are running is another factor.
When hitting it, some runners find it difficult to run and sometimes even walk. If you reach this point, it is okay. Just know what is going on when it happens. It can be a traumatic experience at first because you literally feel empty as if you have nothing left. What do you do? Keep going! Your body will make the transition and you will push through “the wall” to the finish line.
Once you push through, you may experience the “runner’s high” which some runners claim to be better than sex. If this happens, keep going! Remind yourself that you are a marathon runner and feel the feeling you will have when you cross the finish line. In a perfect world, you will deplete the last of your glycogen as you cross the finish line. However, chances are that you will hit the wall. Just remember your preparation, know what is happening, and know you will push through. You can do it! And you will.