Patients who have infectious mononucleosis should not lift weights or engage in any rigorous physical activity, according to Mayo Clinic. Although symptoms usually disappear within a few weeks, patients are still not completely healthy for two to three months.
A common complication of mononucleosis is an enlarged spleen. To avoid rupturing the spleen, Mayo Clinic recommends that contact sports, heavy lifting and general roughhousing should be avoided for a minimum of one month after symptoms disappear. A ruptured spleen is a medical emergency that causes severe internal bleeding. Mayo Clinic states that doctors recommend gradual exercise programs to help patients regain their strengths without injuring themselves. Doctors also recommend adopting a regular sleep schedule to reduce the risk of relapse.