Exercise is good for your immune systems. When you exercise, your body produces white blood cells which fight off infections. Your body also eliminates toxins. Exercise helps prevent diseases like cancer and heart disease. It can also lower stress levels.
But, too much exercise can lead to a weakening of your immune system. You can cause muscle soreness by working out too hard. This can lead to inflammation and swelling. Your body then has to produce more antibodies to fight off infection. These extra antibodies can lead to allergies or autoimmune disorders.
So, don't overdo it!