Mononucleosis, often referred to as “mono,” is a common viral infection primarily affecting adolescents and young adults. Participating in sports with mono carries notable risks, making careful consideration essential before resuming physical activity. Certain aspects of the illness can make athletic endeavors dangerous.
Understanding Mononucleosis
Mononucleosis is primarily caused by the Epstein-Barr virus (EBV), a member of the herpes virus family. It spreads mainly through bodily fluids, particularly saliva, earning it the nickname “the kissing disease.” Symptoms typically appear four to six weeks after exposure, including extreme fatigue, fever, a sore throat, and swollen lymph nodes.
A key characteristic of mononucleosis is an enlarged spleen, and sometimes an enlarged liver. The spleen, located in the upper left abdomen, swells as it filters infected cells and produces immune cells to fight the virus. Most symptoms subside within two to four weeks, but fatigue can linger for several weeks or even months.
Key Sports-Related Risks
The most significant danger for athletes with mononucleosis is the risk of splenic rupture, a serious and potentially life-threatening complication. When enlarged, the spleen becomes fragile and vulnerable to trauma, even from minor impacts or strenuous activity. This vulnerability is heightened because the enlarged spleen may extend beyond the protective rib cage.
Splenic rupture can occur from direct blows to the abdomen, falls, or actions that increase intra-abdominal pressure, such as heavy lifting or intense exertion. Although rare, it is a medical emergency requiring immediate attention. The highest risk for splenic rupture is within the first three to seven weeks of the illness.
Other risks include prolonged fatigue, which impairs performance and increases injury likelihood. Dehydration can also become more pronounced due to fever and illness. Returning to activity too soon can prolong symptoms and lead to complications like liver inflammation.
Guidelines for Returning to Play
Returning to sports after a mononucleosis diagnosis requires a cautious, phased approach and medical clearance from a healthcare professional. The primary factor guiding this decision is the resolution of spleen enlargement and other acute symptoms. While recovery timelines vary, the spleen is most enlarged within the first two to three weeks of illness, with most injuries occurring within 21 days.
Many recommendations suggest a minimum rest period of three to four weeks from symptom onset before considering light activity. For contact sports, guidelines recommend avoiding participation for at least four weeks, and potentially up to eight weeks, due to splenic rupture risk. A gradual return-to-activity plan should begin with light, non-contact exercises like walking, progressively increasing intensity as tolerated.
There is no one-size-fits-all timeline, as individual recovery varies. Athletes should be without fever, well-hydrated, and free of symptoms, including no palpable spleen or liver enlargement, before being considered for return to play. Imaging, such as ultrasound, can be used to assess spleen size, but clinical judgment remains important.
Medical Oversight and Ongoing Care
Medical supervision is essential throughout the recovery and return-to-play process following mononucleosis. Athletes should not attempt to self-diagnose or make independent decisions about when to resume sports. A doctor can monitor spleen size through physical examination and, if necessary, with imaging tests.
The healthcare provider will assess overall recovery, symptom resolution, and provide personalized guidance tailored to the athlete’s specific condition and sport. Individuals should listen to their body and report any new or worsening symptoms, such as sharp abdominal pain, immediately. While most people recover fully, some may experience prolonged fatigue for several months, which may require extended monitoring and a slower return to full activity.