North Carolina Basic Law Enforcement Training (BLET) State Practice Exam

What is the primary fuel source for aerobic exercise?

1. Proteins

2. Fats

3. Carbohydrates

4. Vitamins

The correct answer is: Fats

The primary fuel source for aerobic exercise is carbohydrates. During aerobic activities, the body requires a constant supply of energy over an extended period. Carbohydrates, stored in the muscles and liver as glycogen, are the most readily available energy source during such exercises. They can be quickly broken down into glucose to fuel the muscles when oxygen is present, making them crucial for sustained physical activities like running, cycling, or swimming. While fats can also serve as a fuel source, particularly during prolonged low to moderate-intensity exercise, carbohydrates are more efficient for higher-intensity aerobic activity. Proteins are primarily used for tissue repair and building rather than as a primary fuel source, and vitamins play a vital role in metabolic processes but do not directly provide energy.