The gun fired and off we went. Caught up in the excitement and surrounded by a crowd, I rocketed through the first ten miles without too much trouble. I knew I was running faster then what I had planned, but I thought maybe today was my day. I started to noticeably slow down around mile 15, so I decided to grab a little PowerAde. I felt alright all the way to about mile 21, then the wheels came off. I suddenly felt like garbage and my legs wanted to lock up. To this day I am not sure how, but I managed to grind through the final 5 miles and finish the Fargo Marathon in 2013.
Today I can laugh at how foolish I was on that morning. I bonked, crashed, blew up, hit the wall,whatever you want to call it. Even though it didn’t help, the cause of what happened was not the heat or the fact that I started too fast. The problem came from not fueling appropriately. This is usually the case when someone describes hitting the wall. The good news is that it is preventable and it is possible to get through a race without blowing up. The key to prevention is to understand what is going on biologically. I am not a biologist, so excuse my potentially oversimplified understanding.
Our body utilizes two sources of fuel for energy, glycogen (carbohydrates) and fat. We are always consuming a blend of glycogen/fat, and the percentage of each varies by the intensity of the activity. Because it is more efficient, the more intense the activity, the more glycogen is used. When I started the race faster than I had trained, my body consumed more glycogen then it was used to. The body can store about 1800-2000 calories of glycogen in its muscles and liver. When we hit the wall, our body has consumed all of its glycogen and must revert to consuming fat. Considering that the average person burn a little over 100 calories per mile, it makes sense that most hit the wall around mile 20. It takes a little time for the body to convert GU or sports drinks into glycogen. You can’t chug a bottle and recover instantaneously. This is why it is advantageous to fuel early and often during a race.
During a marathon, I fuel with GU 15 min prior to the start and at miles 9 and 18. I also take water and sports drink at most stations, even if I feel good. It is recommended to fuel every 30 to 45 min during intense activity. Be sure to develop a fueling strategy for yourself and test it during training on long runs. Long runs also train mour body to rely less on glycogen and utilize fat more efficiently. By carbo-loading during the two to three days prior to the race, we can ensure our fuel stores are at full capacity.
Talk to your trainers to come up with your own personal fueling strategy. Rest assured that you don’t have to hit a wall, it is completely avoidable. By working hard, understanding your body, and putting together a plan, you can have confidence in your ability on race day.