Hospitalization may be necessary in patients with rapidly deteriorating respiratory symptoms and treatment includes mechanical ventilation which is associated with a higher mortality risk. To reduce functional exercise capacity loss during a severe exacerbation, studies have been performed to evaluate the effects of lower limb muscle training [3, 7, 8]. Most have assessed the influence of anaerobic training. Troosters et al. (2010) showed improved lower limb muscle strength without increased systemic inflammation after muscle training in hospitalized COPD patients with exacerbation; the authors did not identify adverse clinical events during muscle training. Similarly, in a randomized study of 46 hospitalized COPD patients, Borges and Carvalho (2014) found improved leg strength and quality of life 30 days after discharge in the group who received upper and lower limb anaerobic training during hospitalization and did not observe adverse clinical effects during the training program. However, studies evaluating the adverse effects of aerobic activity in hospitalized patients with exacerbated COPD are scarce in literature. Tang et al. (2012) showed that combined aerobic anaerobic training in exacerbated COPD patients presented 13 adverse events, one with a serious arrhythmia event. However, we found no other studies that had investigated adverse effects related to aerobic training during hospitalization in exacerbated COPD patients.