During exercise, several physiological changes occur in the body. In response to physical activity, the heart rate and respiratory rate increase to supply more oxygen to muscles. Blood flow is redirected from non-essential systems to working muscles, enhancing performance. Additionally, energy production shifts to meet increased demands, utilizing stored carbohydrates and fats. Hormonal changes also take place, releasing endorphins which can improve mood. Collectively, these changes optimize the body's functioning to handle the stresses of exercise effectively.