Question

When an athlete increases the intensity of exercise (for example going from walking, to running a 10k) which of the following is true?

a-A large percentage of the fuel used to the high-intensity exercise will come from carbohydrate
b-A large percentage of the fuel used to the high-intensity exercise will come from fat
c-The percentages of fat and carbohydrate as sources of fuel remain the same during low and high intensity exercise
d-The body switches to lactic acid as the primary source of fuel during intense exercise

Answer 1

During high-intensity exercise, a large percentage of the fuel used comes from carbohydrate.

Step-by-step explanation:

When an athlete increases the intensity of exercise, such as going from walking to running a 10k, a large percentage of the fuel used for the high-intensity exercise will come from carbohydrate. This is because during high-intensity activities, the muscles require more ATP than can be supplied solely through aerobic metabolism, so they rely on both anaerobic and aerobic metabolism.

Carbohydrates, in the form of glucose, provide a quick source of energy through glycolysis, which is especially important when the oxygen supply is insufficient for the increased demand, making them the primary source of fuel for intense physical activities.