Obstructive sleep apnea causes you to have frequent pauses in your breathing; these pauses mean that you actually stop breathing. Sometimes this will cause you to wake up at night but you may not be aware of them. When these breathing pauses happen, the oxygen level in your blood gets low. It is thought that the frequent drops in low oxygen levels during sleep damages the blood vessels that supply the heart. Also, each time the oxygen level drops, your body tells your heart to beat faster and your blood pressure to go up. Stress on the heart from severe OSA can also cause the heart to get enlarged.

This sleepiness can cause accidents at work, poor work performance, and car crashes. Obstructive sleep apnea can also have bad effects on your heart and your blood vessels (arteries, veins, and capillaries). Problems with the rhythm of your heart may occur with OSA such as atrial fibrillation (a type of irregular heart beat) and bradycardia (slow heart rate). People with severe obstructive sleep apnea are four times more likely to have atrial fibrillation compared to those without OSA. Not receiving treatment for your sleep apnea may make your atrial fibrillation difficult to control.