What substance does the body burn during the first seven to ten minutes of cardiovascular training?

During the first seven to ten minutes of cardiovascular training, the body primarily burns glucose, which is derived from glycogen stores in the muscles and liver. The initial phase of exercise relies heavily on anaerobic metabolism, where glucose is the main energy substrate because it can be quickly metabolized to meet the immediate energy demands of physical activity.

As exercise continues beyond this initial period, the body starts to increase the utilization of fat as a fuel source. However, during the early stages of cardiovascular exercise, the demand for rapid energy production makes glucose the more accessible and preferred source. The process of glycolysis allows for quick energy release, facilitating higher intensity performance before fat oxidation becomes more prominent as the duration of exercise increases.

While fat, proteins, and amino acids can also be utilized for energy, they do not serve as the primary fuel during this initial phase of exercise, especially when the body is adjusting to the workload created by physical activity. Protein and amino acids have a much more significant role in recovery and muscle repair rather than as immediate energy sources during cardiovascular training.