Zone 3 refers to a specific area in the context of exercise training, particularly in heart rate zones. It is characterized by moderate to high-intensity workouts, where the heart rate typically ranges from 70% to 80% of an individual's maximum heart rate. Training in this zone helps improve cardiovascular fitness and endurance. In addition to fitness, Zone 3 can also refer to geographical or zoning classifications in urban planning. These zones often dictate land use, such as residential, commercial, or industrial purposes, and help manage development and infrastructure within a community.