One of the most common causes of an ICU admission is a severe episode of acute respiratory failure due either to an exacerbation of chronic pulmonary disease or its ex-novo development after a surgical procedure, trauma or medical complications. These patients usually report, at admission to the ICU, a sedentary life before the acute episode, because the evolution of the disease is characterized by a progressive decline not only in respiratory function (e.g. FEV1), but also in the functional status, due to the effects of lack of exercise, drug administration, malnutrition and, later on, gas exchange abnormalities. Together with specific vital organ support, such as mechanical ventilation, patients admitted to an ICU may require other complex and integrated interventions in order to maintain the spared function and to prevent further damage. These interventions include nutritional and psychological support, counselling, nursing, prevention (e.g. to preserve skin integrity) and in particular a complete physiotherapic program, that may range from simple help to maintain a correct posture to complete recovery of walking autonomy.