The body adapts to increased levels of physical activity through several physiological changes. Initially, the muscular system experiences hypertrophy, which increases muscle size and strength. The cardiovascular system also adapts, improving the efficiency of the heart and lungs, thus enhancing oxygen delivery and utilization during exercise. Additionally, the metabolic processes improve, enabling the body to better utilize energy substrates like carbohydrates and fats. This adaptation occurs over time with consistent exposure to higher intensity and volume of workouts, leading to improved performance and overall fitness levels.