The pre valence of both obstructive sleep apnea and metabolic syndrome is increasing world-wide. The coexistence of obstructive sleep apnea and metabolic syndrome has been termed ”syndrome Z” by researchers. Obstructive sleep apnea is a condition characterized by repetitive obstruction of the upper airway and, consequently, collapsed upper airway that leads to a markedly reduced or absent airflow. There is a large amount of evidence indicating that obstructive sleep apnea is an independent risk factor for cardiovascular morbidity and mortality with a growing body of evidence suggesting that obstructive sleep apnea may be causally related to metabolic syndrome. However, an independent association between obstructive sleep apnea and metabolic syndrome or its components has not fully been established because of a confounding effect caused by obesity on both syndromes. High quality large-scale interventional studies and long-term follow-ups are needed to clarify the cause-effect relationship and the rule that sleep apnea plays in cardiometabolic morbidity. There is no clear consensus of the mechanisms underlying the interaction between obstructive sleep apnea and metabolic syndrome, but researchers have suggested that alterations in the hypothalamic-pituitary-adrenal axis caused by sleep deprivation, generation of reactive oxygen species due to repetitive intermittent hypoxia, systemic inflammation, and generation of adipokines are implicated. Regular exercise has been recommended as a primary strategy for the prevention and treatment of metabolic syndrome, but its effect on obstructive sleep apnea is lacking significant data. Future studies are needed especially to identify if regular exercise has an effect on syndrome Z.