Don’t Hit The Wall

You might hear a runner explaining why she dropped out of a 5K by saying, “I hit The Wall.” Well, now she’s got two strikes against her: Not only did she not finish her race, but she’s misusing runner lingo. Get her a copy of this book and quick! When you get tired in a short race because you’re breathing so hard, that’s fatigue. When you’re doing a run of 90 minutes or more, and you’re feeling fine, and then all of a sudden, bam, every step is a major production and your pace gets way slower, that’s The Wall. Most people can store enough glycogen in their muscles to fuel about 18 to 20 miles of running. When you run long distances, your body senses that it’s getting low on glycogen. It wants to preserve that glycogen, so it starts to burn more fat. At this point, you’re able to maintain your pace, so you keep running. Your body has to keep doling out its precious glycogen stores, and it starts burning more and more fat.
By now, you can keep up your pace, but you have to work a little harder to do so because fat doesn’t burn as efficiently as glycogen when it comes to fueling your running. But you keep running because you were idiotic enough to listen to me when I told you how great the marathon is. Now your glycogen stores are getting very low, and you’re burning more and more fat.
That wouldn’t be all bad, except for this fact: Fat burns on a flame of glycogen. To keep running at your normal pace, you need at least enough glycogen to help burn the fat. But you’ve pretty much used it all up. You’re primarily burning fat, and fat takes a lot more oxygen to burn than glycogen does. As a result, you have to slow down dramatically, sometimes by more than two minutes per mile. You will want nothing more than to lie down by the side of the road. To top it off, you’ve also depleted the small amount of glycogen that’s stored in your liver. Your liver is supposed to feed this glycogen into your bloodstream to maintain your blood sugar well enough to feed your brain glucose. When this process starts breaking down, you feel woozy, light-headed, uncoordinated. Great!
You want to lie down by the side of the road, and now you’re getting so uncoordinated that you just might have your wish fulfilled. You’ve got as many as eight miles to go. Unless you’ve got incredible willpower, you’re a leading candidate to join the DNF list.
So how do people ever survive marathons? First and most important, they train. Long runs improve your body’s ability to store glycogen. Runners who do marathon training can store more than twice as much glycogen in their muscles as untrained people. Your body can get more fuel from the food that you eat when you train properly.
Also, marathoners start their marathons at a pace they know that they can maintain to the finish. The faster you run, the more glycogen you burn. Going out too fast in a marathon is a huge mistake, because even at a reasonable pace you’re going to need every last bit of glycogen that you can get. One trick that runners do to make sure that they don’t go out too fast in the marathon is to run the first mile one minute slower than the pace that they hope to average for the distance.
Even if you do the right training and pace yourself well in the marathon, The Wall can be pretty daunting. But what you do in the few days before the marathon can push it past the finish line.