There is a close and complex interaction between stress and the immune system. Long term or excessive psychological stress can activate the stress response system of the human body, leading to a sustained increase in stress hormones such as cortisol, which in turn inhibits the activity of immune cells and reduces the body's ability to recognize and eliminate pathogens. Research has shown that chronic stress may reduce the number of natural killer cells, weaken the function of T lymphocytes, and delay the wound healing process, thereby increasing the risk of infection, prolonging disease recovery time, and even affecting the immune response after vaccination. On the contrary, a healthy immune state also helps maintain good emotional regulation ability, forming a positive feedback loop between body and mind. Therefore, scientific management of stress, maintaining a regular schedule, balanced nutrition, moderate exercise, and cultivating a positive psychological state are important foundations for maintaining normal immune system function and improving overall health.