Which energy pathway is used for sustained physical activities over a long period?

The aerobic energy pathway is utilized for sustained physical activities over longer durations because it is capable of producing ATP through the oxidation of carbohydrates and fats in the presence of oxygen. This pathway supports activities that are performed at moderate intensity and can last from several minutes to hours, such as distance running, swimming, or cycling.

During prolonged exercise, the body relies on oxygen to break down nutrients to generate energy, allowing for continuous muscle contraction without the rapid accumulation of lactic acid, which can lead to fatigue. The aerobic system becomes more efficient with training, enhancing a person's endurance and ability to perform at longer durations without significant fatigue.

In contrast, the anaerobic pathways, including lactic and alactic systems, provide energy for short bursts of high-intensity activity but are not sustainable over extended periods. The anaerobic lactic system, for instance, is primarily utilized during moderate to high-intensity efforts that last from about 30 seconds to 2 minutes, while the anaerobic alactic system (also known as the ATP-CP system) fuels very short, explosive activities, typically under 10 seconds. Therefore, for long-duration activities where endurance is required, the aerobic pathway is the primary source of energy.