Sleep Apnea There are two main types of sleep apnea, obstructive and central, and a third that is a combination of those two which we will call mixed. OBSTRUCTIVE SLEEP APNEA (OSA) Approximately 60 million Americans are victims of a sleep disorder called Obstructive Sleep Apnea (OSA).   Many millions more are predisposed and have a high risk of developing the illness. If you are an adult male, the odds are about 50/50 that your breathing is not normal when you are sleeping.  It is imperative that anyone who might have this problem or is predisposed, or knows someone they care about who has the problem, should have the clearest possible understanding about it. We have dedicated this section of the web site to a crystal clear and detailed description of all aspects of obstructive sleep apnea. The section begins with an overview which will introduce the reader to this important sleep disorder. During the next several weeks we will be providing you with a more in-depth understanding of obstructive sleep apnea. Please check back to this section to view upcoming segments. What is Obstructive Sleep Apnea (OSA)? People with OSA experience recurrent episodes during sleep when their throat closes and they cannot suck air into their lungs (apnea). This happens because the muscles that normally hold the throat open during wakefulness relax during sleep and allow it to narrow. When the throat is partially closed and/or the muscles relax too much, trying to inhale will suck the throat completely closed and air cannot pass at all. This is an obstructive sleep apnea episode. A cessation of breathing must last 10 seconds or more to be called an Apnea. Obstructive apnea episodes can last as long as two minutes and are almost always associated with a reduction in the level of oxygen in the blood. When an individual is in the midst of an obstructive sleep apnea episode, as long as sleep continues, the apnea continues.  It is only terminated and the victim's life is saved by waking up. This arousal instantly increases the activity of the muscles of the tongue and throat muscles that enlarge the airway.  The victim will be able to breathe and to once again fill the lungs with life-giving oxygen.  This cycle may be repeated hundreds of times a night while the sufferer has no idea it is happening.   What is Central Sleep Apnea (CSA)? Central sleep apnea is caused by a delay in the signal form the brain to breath . With both obstructive and central apnea you must wake up briefly to breathe, sometimes hundreds of times during the night. Usually there is no memory of these brief awakenings.