Post-intensive care unit (ICU) syndrome may occur after ICU treatment and includesICU-acquired weakness (ICU-AW), cognitive decline, and mental problems. ICU-AWis muscle weakness in patients treated in the ICU and is affected by the period of mechanicalventilation. Diaphragmatic weakness may also occur because of respiratorymuscle unloading using mechanical ventilators. ICU-AW is an independent predictor ofmortality and is associated with longer duration of mechanical ventilation and hospitalstay. Diaphragm weakness is also associated with poor outcomes. Therefore, pulmonaryrehabilitation with early mobilization and respiratory muscle training is necessaryin the ICU after appropriate patient screening and evaluation and can improve ICU-relatedmuscle weakness and functional deterioration.