Sleep Apnea News - What are the types of sleep apnea? 

Sleep apnea is formally defined as an apnea-hypopnea index of at least 15 episodes/hour in a patient if they do not have medical problems that are believed to be caused by the sleep apnea. This is the equivalent of approximately one episode of apnea or hypopnea every 4 minutes. High blood pressure, stroke, daytime sleepiness, congestive heart failure (low flow of blood to the heart), insomnia, or mood disorders can be caused or worsened by sleep apnea. In the presence of these conditions, sleep apnea is defined as an apnea-hypopnea index of at least five episodes/hour.

This definition is stricter because these individuals may be already experiencing the negative medical effects of sleep apnea, and it may be important to begin treatment at a lower apnea-hypopnea index.

• central sleep apnea (CSA),
• obstructive sleep apnea (OSA), and
• mixed sleep apnea (both central sleep apnea and obstructive sleep apnea).
  

During sleep, the brain instructs the muscles of breathing to take a breath.
Central sleep apnea (CSA) occurs when the brain does not send the signal to the muscles to take a breath, and there is no muscular effort to take a breath. Obstructive sleep apnea (OSA) occurs when the brain sends the signal to the muscles and the muscles make an effort to take a breath, but they are unsuccessful because the airway becomes obstructed and prevents an adequate flow of air. Mixed sleep apnea, occurs when there is both central sleep apnea and obstructive sleep apnea.