In which situation does the aerobic system primarily provide energy?

The aerobic system primarily provides energy during physical activities that are sustained for longer periods, typically starting to dominate after about 10 minutes of continuous exercise. This system relies on the presence of oxygen to metabolize carbohydrates and fats, producing energy for prolonged, moderate-intensity activities such as distance running, swimming, or cycling.

When exercise lasts for more than 10 minutes, the body shifts from anaerobic pathways—which primarily supply energy during short bursts of high-intensity activity—to the aerobic system. This transition allows for a more efficient and sustainable energy output, as the aerobic system supports lower-intensity, longer-duration efforts.

In contrast, shorter activities of high intensity rely primarily on the anaerobic system, which can rapidly produce energy without oxygen but is limited in duration and leads to quicker fatigue. Consequently, while the aerobic system is vital for endurance and longer activities, it typically becomes the dominant source of energy after several minutes of continuous exertion.