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. Cardiac output and cardiac stroke volume may decrease during systemic febrile viral infections. Acute viral respiratory tract infections can affect pulmonary function. For example, research studies have shown respiratory infections to impair pulmonary gas exchange, though the impairment is not serious. Additionally, rhinovirus infection may produce transient peripheral airway abnormalities, which are detected by measuring the dynamic compliance of the lungs and also are not serious.