Vitacca M, Paneroni M, Braghiroli A, et al. - In this investigation involving 1,228 patients, researchers to assess exercise capacity, as evaluated by the six minutes walking distance test (6MWD) in large populations with obstructive sleep apnea (OSA) and to explore the associations with patients’ comorbidities. According to results, a high rate of patients with OSA suffers from exercise limitations. It was noted that 6MWD positively associated with apnea-hypopnea index, oxygen desaturation index, nocturnal SpO₂, resting arterial oxygen tension, mean SpO₂ on exercise, and negatively with age, BMI, time spent during the night with SpO₂< 90%, mean nocturnal desaturation, arterial carbon dioxide tension and number of comorbidities. Findings suggested an association of older age, comorbidities as COPD and CRF, OSA severity class I, severe mean nocturnal desaturation and daytime hypoxemia with worse exercise tolerance.