Obstructive form of apneas/hypopneas where there is an intermitent complete or partial closure of the upper respiratory tract due to the abundance of soft tissues or the anatomy of face/skull, causes a decrease of airflow through the upper airway passages. As a consequence blood oxygen desaturation emerges and its intensity or depth depends on the arousal of the sympathetic nervous system. Particular reactions to the repetitive hypoxia due to apnea might cause vasoconstriction and endothelial dysfunction which is after a certain period of time followed by arterial hypertension (5). Similar mechanisms take place in central forms of apneas. In certain cases, due to breathing effort in apneas or hypopneas, patients awaken to prevent the drop of the saturation level, which is also known as RERA (Respiratory Effort Related Arousals) and this is usually known to preceede OSA.

At the same time in case of apneas, hypercapnia (increased blood CO2 level) together with hypoxia can occur and can lead to arterial hypertension as well (6,7).

People with OSA Syndrome are especially prone to suffer from obesity and what is more, obesity can cause the OSA syndrome. There might be a vicious circle combining obesity and the OSA syndrome. (5,8)

Pathophysiological mechanisms of the formation of diabetes in case of apneas (8):