"How does exercise affect your immunity"

Immunity of exercise is a mixed message as it relates. Regular, moderate-intensity physical activity has been shown to help protect people against some diseases, particularly those that involve the upper respiratory track (like colds). However, too much exercise beyond normal limits can reduce immunity and can have the opposite effect. The keys are (1) knowing how much exercise is enough, (2) when exercise is appropriate and when it's not, and (3) which types of exercise are appropriate for your particular situation. Here are the details.
                                         
Exercise and Immunity by the Numbers

2-3 

The average adult gets per year number of upper respiratory infections as per practice.

2

The number of weeks a person should wait before engaging in intensive physical training after serious “below the neck” symptoms (coughing, vomiting, diarrhoea) caused by a respiratory infection.

25 – 50 

Active people who complete at least 45 minutes of moderately-intensive exercise most days of the week, the percentage of decrease in sick time for how exercise Works to Boost Immunity.

                             
Most of the research on exercise and immunity has been done with colds and there's a considerable amount of research showing that regular, moderate exercise enhances the immune system. Athletes had a lower incidence of colds when they were engaged in a running program, several studies reported that recreational exercisers and exercise has been shown to increase the production of macrophages. These are cells that attack the kinds of bacteria that can trigger upper respiratory diseases. The immune system that happen when a person exercises, more recent studies show that there are actually physiological changes in. Cells that promote immunity circulate through the system more rapidly, and they're capable of killing both viruses and bacteria. A regular exercise routine appears to extend periods of immunity after exercising, the body returns to normal within a few hours.

                                                
Some people believe that the temporary rise in body temperature that occurs during exercise may inhibit the growth of bacteria. This process allows the body to fight infection more effectively. Stress is shown to increase the likelihood of illnesses, exercise also slows the release of stress-related hormones. Dr David Nieman, an exercise immunologist at Appalachian State University, is one of the country’s most respected authorities in this area. One of his studies showed that people who walked at 70 to 75 percent of their VO2max for 40 minutes per day reported half as many sick days because of colds or sore throats compared to people who didn't exercise.

Exercise affecting immunity negatively                             
However, too much exercise appears to negatively affect immunity. 90 minutes or more of high-intensity exercise (marathons, endurance races) makes a person more susceptible to illness as per a study which found that for up to 72 hours after working out. During exercise, the body produces two hormones, cortisol and adrenaline, that raise blood pressure, elevate cholesterol levels, and temporarily weaken the immune system. 

Increase the presence of stress-related hormones, heavy, long-term exercise could increase the amount of white blood cells. Marathon and triathlon athletes are particularly vulnerable to increased susceptibility to infection, although susceptibility doesn't automatically lead to infection.

Exercising While Sick
If you have "above-the-neck" symptoms (runny nose, sneezing, sore throat)It's typically safe to exercise at a low intensity. If those symptoms diminish during the first few minutes of exercise, the intensity may be increased. For people with “below-the neck” that produces mucous symptoms, (fever, sore muscles or joints, vomiting, diarrhoea, or a cough) exercise is not recommended. If you have those symptoms, let the cold run its course before you resume physical activity.

Below-normal exercise intensity for each day you were sick before jumping back into your normal training routine, wait two weeks after symptoms subside before engaging in intensive training. When you do return to training, allow two days of.

Dr. Nieman recommendations include:

Exercise, but don't overtrain, if you just have a head cold.

If your cold etc. involves other parts, systems, or organs of the body, don’t exercise if your cold or other illness is “systemic”—that is, engage in moderate exercise before getting a flu shot. The physical activity could improve your body’s response to the vaccine and enhance your immunity to the flu.