Sleep apnea is a condition that causes the patient to stop breathing at various times throughout the night. Studies show that such patients usually have pauses in normal breathing hundreds of times each night, each episode lasting up to 30 seconds, if not longer. There are three types of sleep apnea: obstructive, central, and complex. Each one is identified by abnormal periodic cessation of breathing, though the cause of the cessation is different for each apnea type. Obstructive sleep apnea is caused by a blockage within the airway that impedes the natural flow of air. Central sleep apnea occurs because the brain does not send the proper signals to muscles that control breathing. Complex sleep apnea is a combination of these two. This makes diagnosis even more vital as it is important to not only know if you have sleep apnea, but to further know what type you have in order to receive proper treatment.