Sleep Apnea is characterized by brief interruptions of breathing during sleep. Apnea is a Greek word meaning "without breath." An apnea is cessation of breath that lasts at least 10 seconds.
"Hypopnea" also comes from Greek: "hypo" meaning beneath or less than normal and "pnea" meaning "breath." A Hypopnea is not a complete cessation of breath, but is reduced airflow that leads to sleep disruptions or to a decrease in the oxygen level in the bloodstream.
The apnea-hypopnea index (AHI) refers to the total number of apneas and hypopneas divided by the total sleep time in a patient's sleep study. It is the number of times per hour during sleep that the airway partially or completely collapses. The AHI gives one measure of the severity of the sleep apnea.
There are 3 types of APNEA: Obstructive, Central, and Mixed (a combination of obstructive and central). Obstructive sleep apnea (OSA) is the most common. Typically, the soft tissue in the back of the throat collapses, limiting or stopping the flow of air, resulting in sleep apnea. Sleep apnea affects males and females of all ages, and body weights.
Symptoms of sleep apnea are loud snoring, excessive daytime sleepiness, fatigue, choking or gasping during sleep, morning headaches, memory or concentration issues, depression and waking frequently to urinate. Untreated sleep apnea can be life threatening, consequences may include high blood pressure, stroke and other cardiovascular complications. More than 12 million Americans suffer from sleep apnea, and an estimated 10 million remain undiagnosed.