What is the primary fuel that the body uses during high-intensity physical activities like firefighting?

During high-intensity physical activities such as firefighting, the primary fuel that the body utilizes is carbohydrates. When engaging in strenuous exercises, the body relies heavily on glucose, which is derived from carbohydrates, as it provides a rapid source of energy. This is crucial in firefighting scenarios where quick bursts of activity are necessary, and the demand for energy is significantly elevated.

Carbohydrates can be stored in the muscles and liver as glycogen, which can be quickly mobilized to meet the energy demands of the body. Unlike fats, which are more efficient for low-intensity, prolonged activities, carbohydrates can be metabolized quickly and efficiently under intense conditions, making them the preferred fuel source in high-demand situations.

While other substances mentioned may have roles in the body, they do not serve as the primary energy source during high-intensity activities. Salts are essential for various physiological functions but do not directly provide energy. Pure sugar can provide energy but is generally part of broader carbohydrate intake rather than being a standalone fuel source. Nitrates may enhance blood flow and aerobic performance but do not function as direct energy sources in the same way that carbohydrates do.