The direct consequence of hypopnea (as well as apnea) is that the CO₂ in the blood increases and the oxygen level in the patient’s blood decreases proportionate to the severity of the airway obstruction. This disruptive pattern of breathing generates disruptive sleep patterns, the consequences of which being that those individuals exhibit increased fatigability, lethargy, decreased ability to concentrate, increased irritability, and morning headaches. Basically, those individuals are extremely tired due to their inability to get a good night’s sleep.