Exercise Duration & Fuel Selection

The video tutorial by Kevin Tolkoff explains how fuel sources change with exercise intensity and duration. At lower intensities, fat is the primary fuel, while at higher intensities, carbohydrates dominate. As exercise duration increases, the body shifts from using carbohydrates to fats due to limited glycogen stores. The video also discusses energy storage in glycogen and the role of adipose tissue in prolonged exercise. Key differences between fuel usage based on intensity and duration are highlighted.

What happens to the reliance on carbohydrates as exercise intensity increases?

• It decreases.

• It fluctuates randomly.

• It remains the same.

• It increases.

During prolonged exercise at a constant intensity, what happens to the reliance on fats?

• It remains constant.

• It increases.

• It becomes negligible.

• It decreases.

Why does the body rely more on fats during prolonged exercise?

• Glycogen stores deplete over time.

• Carbohydrates are unlimited.

• Fats are easier to metabolize.

• Fats are stored in the liver.

What is the primary storage form of carbohydrates in the body?

• Amino acids

• Plasma glucose

• Glycogen

• Triglycerides

What is a key difference between fuel source variation with intensity and duration?

• Intensity affects fat reliance more.

• Duration affects carbohydrate reliance more.

• Intensity and duration have the same effect.

• Duration affects fat reliance more.

Why is it difficult to observe fuel source shifts at high exercise intensities?

• High intensities lead to lactic acid buildup.

• High intensities can be sustained for long periods.

• High intensities rely solely on fats.

• High intensities are below the lactate threshold.

At what exercise intensity is it most feasible to observe the shift from carbohydrate to fat reliance over time?

• 50% VO2 Max

• 100% VO2 Max

• 10% VO2 Max

• 80% VO2 Max