Regular exercise positively impacts the immune system by enhancing its functionality. Moderate physical activity can improve circulation, allowing immune cells to move more freely and efficiently throughout the body. Furthermore, exercise supports the body's stress response by lowering levels of stress hormones, which can suppress the immune system. Consistent activity can help prevent chronic illnesses, leading to overall better health. However, it's worth noting that excessive exercise, without adequate recovery, can have a counterproductive effect, so moderation is key to maintaining a robust immune defense.