Exercise may improve your immune system by altering defense mechanisms and your mental states. Your immune system relies on substances in your body that detect threats and activate other immune cells that fight off invasion. Exercise may influence the levels of detecting and fighting cells in your body. Exercise may also indirectly affect your immune system by affecting your hormone levels.
Interleukin-1
Moderate exercise may improve your immune system by increasing the production of an immune system stimulant known as interleukin 1, which stimulates your immune system by increasing lymphocyte activity. Lymphocytes are a type of white blood cell that fight infections, and interleukin 1 helps these cells pass through blood vessel walls to reach and treat infection sites. Interleukin 1 also produces a fever when you are sick by affecting areas in your brain that control body temperature.
Interferon
Interferon protects you from constant exposure to millions of germs that can lead to disease and infection. Your immune system activates interferon when viruses attack cells in your body. Interferon communicates with neighboring cells and signals their resistance mechanisms. Interferon is essential to prevent infections, because it activates immune cells that are responsible for killing invading pathogens. Moderate exercise increases your body's production of interferon, and your levels may remain elevated for around two hours after exercise.
Stress
Stress may alter your immune system by affecting your susceptibility to mental and physical diseases, and the severity of these diseases. Your hormonal system and immune system interact and may change the way your immune system normally reacts. Hormonal changes typically fade away when you perceive short-term stress, but your immune system may initiate an inflammatory state when you perception of stress lasts too long. An uncontrolled inflammatory state produces symptoms that may progress and establish the process for particular diseases. Exercise improves your immune system by reducing short-term and long-term stress, enhancing your coping mechanisms and increasing your sense of well-being. The University of New Mexico adds that exercise also reduces anxiety, depression and hostility.
NK Cells
Natural killer, or NK, cells are highly active immune cells. Your immune system uses NK cells to fight viral infections and cancer cells. Athletic exercise such as rowing, running and cycling may boost NK cell activity in your body for most of the day. Intensive training produces stressful changes in your body that can suppress immunity. However, your immune system may adapt by increasing NK cell activity to combat the negative effects of intense training, notes Fitness.gov.
