Infections in Athletes

In 1994, Nieman demonstrated a relationship between exercise and susceptibility to infections in the form of a J -shaped curve.

• The model suggested that whereas engaging in moderate activity enhances immune function above sedentary levels, excessive amounts of prolonged high-intensity exercise have detrimental effects on immune function.

Gleeson found postexercise immune function depression was most pronounced when exercise is moderate to high intensity, continuous, and prolonged.

Leukocyte function may continue to remain depressed at 24 hours after the last exercise bout.

If the recovery time between consecutive bouts of intense exercise is insufficient, chronic immunosuppression can occur, which is often observed in overtrained athletes.

Fever is a normal physiologic response to infection, with the intent to increase host survival and decrease the length of illness.

The Centers for Disease Control and Prevention (CDC) defines fever as an internal temperature of >100.4°F (38°C).

Fever can cause undesirable effects in the body, including increased insensible fluid losses, dehydration, increased metabolic demands, and body temperature dysregulation.

Hyperthermia with dehydration leads to a reduction in both cardiac output and blood pressure. This concerning combination can lead to reduced exercise tolerance, endurance, and muscle strength.

Exercising during a febrile illness can further potentiate negative effects from the disease process and can evolve into potentially lethal myocarditis from viral illnesses.

Athletes should be withheld from physical activity until their fever has resolved, and return to participation should be gradual.

To decrease the spread of infections, hand washing is the most common and effective method. Separating an athlete from the team also helps.

Etiology: An upper respiratory tract infection (URTI) is a common cold. It is caused by respiratory viruses, usually rhinoviruses. Transmission is through nasal secretions by sneezing, coughing, and nose blowing.

Epidemiology: Cough is the 3rd, whereas nasal congestion is the 15th most common presenting symptom in all office visits. URTIs are the 3rd most common primary care diagnosis.

Symptoms: URTIs are self-limited, lasting up to 10 days with symptoms of fever, cough, rhinorrhea, nasal congestion, sore throat, headache, and myalgias.

Examination and diagnosis: Fever, rhinorrhea, erythema, cobblestoning or swelling of the posterior oropharynx, fluid level behind the tympanic membrane, and cervical lymphadenopathy; diagnostic testing is only necessary to diagnose group A streptococcal or mononucleosis infections. Influenza and COVID-19 are discussed separately.

Treatment: Treatment is symptomatic and supportive and includes antipyretic and nonsteroidal anti-inflammatory drugs (NSAIDs), decongestants, nasal saline irrigation, intranasal ipratropium, and zinc. Antibiotics are ineffective.

Return to play (RTP): The “neck check” is a helpful tool when considering whether physical activity is appropriate. An afebrile athlete with URTI symptoms “above the neck,” without systemic signs or symptoms, may attempt 10–15 minutes of mild to moderate exercise and, if tolerated, may participate as tolerated.

Prevention: Encourage hand washing. No sharing of water bottles.