A strong immune system is vital for overall fitness as it defends the body against infections and diseases. When the immune system is functioning well, individuals can engage in exercise more regularly and recover quickly from physical stressors. Enhanced immunity reduces the risk of illness, allowing for a consistent fitness routine without frequent interruptions. Moreover, regular physical activity itself contributes positively to immune health by promoting circulation and reducing inflammation. In conclusion, a robust immune system supports sustained physical activity and improved overall health.