Core Points - The phenomenon of "hitting the wall" during endurance sports like marathons is characterized by sudden energy depletion, leading to extreme fatigue and loss of control over bodily movements [3][4][8] - Glycogen depletion is a primary cause of this condition, as the body relies on glycogen stored in muscles and the liver for energy during high-intensity exercise [6][7] - The experience of "hitting the wall" can lead to physical symptoms such as muscle cramps, accelerated heart rate, and impaired cognitive function [8][11] Summary by Sections Energy Depletion - "Hitting the wall" refers to a state of sudden energy exhaustion experienced by athletes during endurance events [3] - The body primarily uses glycogen for energy during high-intensity activities, and a typical person can deplete their glycogen stores after approximately 2-3 hours of running without supplementation [7] Physiological Responses - When glycogen is depleted, the body must switch to fat as a fuel source, which is a slower process requiring reduced exercise intensity [10] - Symptoms of "hitting the wall" include extreme fatigue, muscle spasms, and a feeling of mental disorientation [8][11] Prevention Strategies - Professional athletes are less likely to "hit the wall" due to better training, stronger cardiovascular systems, and experience in managing their energy levels [12] - Strategies to avoid this condition include regular energy supplementation during races, proper hydration, and carbohydrate loading in the days leading up to the event [15]