Which phase of metabolic response is characterized by predominantly aerobic metabolism?

The phase characterized by predominantly aerobic metabolism is Phase 1. During this initial phase of the metabolic response, the body primarily relies on oxygen to convert carbohydrates and fats into energy, supporting physical activity and recovery processes. Aerobic metabolism is efficient for producing energy in the presence of oxygen and is utilized during lower-intensity and sustained activities.

In contrast, subsequent phases may shift towards anaerobic metabolism as physical demands increase or as the duration progresses, leading to different energy production mechanisms. This phase's focus on aerobic processes underscores the importance of oxygen in maintaining energy levels during the body's response to exercise or other stressors.