Topic 13

The immune system protects the body from infectious disease. It is involved in tissue repair and protection against potential pathogens

Limit to the following. * Innate: – Physical: skin, epithelial linings, mucosal secretions – Chemical: pH of bodily fluids, hormones and other soluble factors – Leucocytes: white blood cells that fight disease * Adaptive: – Inflammation – Clotting – Lymphocyte and antibody production

An intense bout of exercise can cause tissue damage and so is accompanied by responses that are similar to those of an infection, such as: * increase in leucocytes (dependent on theduration and intensity of exercise) * inflammation. When training loads are high and prolonged, there tends to be a decrease in innate and adaptive immune function. * Sustained increases in levels of cortisol and adrenaline over long periods suppress the immune system. Leucocyte numbers drop compared to sedentary people

Athletes are more susceptible to infections than their sedentary peers because of: * lower leucocyte numbers caused by the stress of the exercise * inflammation caused by muscle damage * greater exposure to airborne bacteria and viruses because of an increased rate and depth of breathing. The relationship between exercise intensity and susceptibility to disease can be seen as a J curve because an elite athlete has not only to be physically fit but also have an immune system able to withstand infections, even during severe physiological and psychological stress. Moderate exercise, however, is associated with reduced susceptibility to infection

Incorporation of sufficient recovery time into training programmes. * Avoid close contact with people with infections. * Maintain oral hygiene. * Maintain hydration status. * Ensure water is pathogen-free. * Maintain good personal hygiene (for example, washing hands, avoiding hand-to mouth contact). * Maintain a suitable and varied diet. * Ensure sufficient sleep.