Chicago Symphony Orchestra music director Riccardo Muti has been diagnosed by doctors in Milan with “extreme exhaustion as a result of prolonged physical stress,” the CSO reports in a statement released today. He’s been prescribed a month of complete rest and is expected to return to Chicago for scheduled performances in February. According to the statement, the maestro puts it this way: “After a terrible storm, even if the wind dies down and the skies have cleared, it takes a while for the waves to calm down fully.”