Answer: The body's reaction to long-lasting stress is associated with impaired immune response.
The body immune system is the first defence mechanism against any invading pathogens, physical and mental stress. There are two ways by which stress can affect the immune system: firstly by the creation of chronic inflammation harming the tissues and secondly by the suppression of the immune cells for fighting the infection.
During stress or fight-or-flight condition, body starts to produce more amount of cortisol which is a stress hormone. The immune system is suppressed by lowering the amount of the protein needed to signal the immune cells. This reduces the number of lymphocytes or B cells and T cells.