What system provides the primary energy required for long-duration activity?

The aerobic system is responsible for providing the primary energy required for long-duration activities. This system relies on oxygen to convert carbohydrates, fats, and, in some cases, proteins into energy over extended periods. It is particularly effective during sustained, lower-intensity activities such as long-distance running, cycling, or swimming, where the body can efficiently maintain energy production for hours.

In contrast, the anaerobic system primarily supports short bursts of high-intensity efforts, where oxygen is not available to meet energy demands quickly. The phosphagen system generates immediate energy for short, powerful movements like sprinting or weightlifting but depletes rapidly. The lactic acid system provides energy for moderate-to-high intensity activities lasting around 30 seconds to 2 minutes, after which fatigue sets in. Therefore, for long-duration activity, the aerobic system is the most suitable and is the primary energy pathway utilized by the body.