Dr. Steven Polansky, who has run the CIM every year for 18 years, agrees. That's basically when you run out of fuel. Your body becomes inefficient. He explains that a runner's body first uses the glucose in the bloodstream, then the glycogen in the muscles, finally the liver. When all this happens, you run out of gas.
Runners have a term for it.
About 5 percent of the runners will drop out at the wall. Medical personnel says they probably treat more people at this point than at the finish line. Once you past this things become much easier. And most people will get past this point. That's important to remember.