This may be related to suppression of the immune system during exercise. Exercising with an infection also carries some disease-specific health risks. Symptoms of a respiratory tract infection, for example, may worsen with exercise. These infections are often associated with inflammation of the airways and increased bronchial secretions. In individuals with asthma or reactive airways caused by a respiratory tract infection, strenuous exercise may cause bronchospasm, with increased cough, wheezing, and dyspnea.
Splenic rupture is a potentially fatal complication of infectious mononucleosis.
For strenuous and contact sports, patients can resume activity approximately 1 month after the onset of the illness if the spleen is not enlarged on palpation. Another group of diseases that might be worsened or complicated by exercise is infection with enteroviruses such as coxsackieviruses. A different factor to consider in determining playability is impaired performance. Acute illness can hinder athletic performance by influencing several different body systems. Cardiac function may be altered during acute infections, especially those accompanied by fever.