During high-intensity exercise, which process becomes predominant?

During high-intensity exercise, the body primarily relies on glycolysis, which is the process of breaking down glucose to produce energy rapidly. This process is anaerobic, meaning it does not require oxygen, and it is particularly crucial when the demand for energy exceeds the oxidative capacity of the cells.

During such intense physical activity, the muscles require a quick supply of energy, and glycolysis delivers that energy efficiently by converting glucose into pyruvate, which can then be further converted into lactate when oxygen levels are insufficient. The accumulation of lactate during high-intensity exercise indicates a switch from aerobic metabolism to anaerobic metabolism, as the body cannot keep up with the energy demands through oxygen-dependent pathways.

While aerobic metabolism and fat oxidation are important for energy production during lower-intensity, prolonged exercises, they do not provide energy at the same fast rate required during high-intensity activities. Meanwhile, protein synthesis is not a primary energy production method and occurs more in recovery periods rather than during exercise. Thus, during high-intensity workouts, glycolysis becomes the preferred pathway to meet immediate energy demands.