Another point related to adverse clinical events was the beginning of exercise training after hospitalization. Our study showed no negative clinical effects beginning after 72 hours of hospitalization. We did not find any recommendations in literature about the right time to initiate aerobic training during hospitalization . There are careful recommendations for initiating training in the 48 hours after admission. For instance, Greening et al.  evaluated the muscular rehabilitation associated with aerobic exercise and early neuromuscular stimulation in hospitalized COPD patients. They found no difference between intervention and control groups in hospital readmission rate. However, there was an increased mortality risk after 12 months in patients who received intervention during hospitalization. On the other hand, other studies which began exercise after 48 hours hospitalization showed no negative outcomes, but those studies did not follow patients for more than one month [21, 22].