When faced with foreign attacks, our immune system steps in. It releases white blood cells and other chemicals that destroy these foreign threats.
When we’re sick, the stress from an intensive workout can be more than our immune systems can handle.
Non-strenuous stretches and exercises, however, shouldn’t hurt, and it might actually even help. These non-strenuous exercises include walking and low-intensity bike riding. In fact, these activities aren’t vigorous enough to create some serious immune-compromising stress on the body. Instead, they are proven to boost immunity and promote faster recovery.
Consistent, moderate exercise and resistance training can strengthen the immune system, and single, high intensity exercise sessions can interfere with immune function.
Given these, it’s good to avoid high-intensity exercises when you’re feeling sick. Sudden increases in exercise volume/intensity may create stress, potentially allowing a new bacteria to take hold, thus again kicking off a sickness.