The syndrome of obstructive sleep apnea during hypopnea/apnea events, poor alveolar ventilation reduce the oxygen saturation in arterial blood and lead to a consequent oxidative imbalance as a result of intermittent hypoxia, with production of reactive oxygen species, the factors of tumor necrosis, inflammatory cytokines (IL-2, IL-4, IL-6), lipid peroxidation and cell-free DNA. This evidence concerns the gene IL6 and obstructive sleep apnea syndrome.