The Facts About Sleep Apnea
Apnea is the Greek word which translates to “Without Breath.”
There are three types of sleep apnea:
- Central – The Brain fails to send the appropriate signal to the body to breathe
- Obstructive – Interrupted breathing from a physical blockage to airflow
- Complex – A combination of Central/obstructive where the interrupted breathing transitions between the two types
Obstructive sleep apnea is the most common type consisting of approximately 84% of all cases, central apnea at 0.4%, and complex apnea at 15%. This condition is usually diagnosed by sleep testing via Home Sleep Testing (HST) or a traditional sleep lab study.
Obstructive sleep apnea (OSA) is a sleep-related breathing disorder that involves a decrease or complete halt in airflow despite an ongoing effort to breathe. It occurs when the muscles relax during sleep, causing soft tissue in the back of the throat to collapse and block the upper airway. This leads to partial reductions (hypopneas) and complete pauses (apneas) in breathing that last at least 10 seconds during sleep. Most pauses last between 10 and 30 seconds, but some may persist for one minute or longer. This can lead to abrupt reductions in blood oxygen saturation, with oxygen levels falling as much as 40 percent or more in severe cases. The brain responds to the lack of oxygen by alerting the body, causing a brief arousal from sleep that restores normal breathing. This pattern can occur hundreds of times in one night. The result is a fragmented quality of sleep that often produces an excessive level of daytime sleepiness.
Most people with OSA snore loudly and frequently, with periods of silence when airflow is reduced or blocked. They then make choking, snorting or gasping sounds when their airway reopens. Most individuals aren’t aware that they are having difficulty breathing even upon awakening.
A common measurement of sleep apnea is the apnea-hypopnea index (AHI). This is an average that represents the number of apneas combined with the number of hypopneas that occur per hour of sleep. These episodes are considered significant when there are five or more episodes per hour.