Sleep apnea is a common sleep disorder characterized by repeated interruptions in breathing during sleep. These pauses or shallow breaths can occur many times throughout the night, leading to disturbed sleep and potentially impacting overall health. Understanding what constitutes typical breathing patterns versus problematic events is important for recognizing this condition.
Understanding Sleep Apnea Events
Sleep apnea involves two primary types of breathing disruptions: apneas and hypopneas. An apnea is a complete cessation of airflow through the nose and mouth, meaning breathing stops entirely. For an event to be counted, this pause in breathing must last for at least 10 seconds.
A hypopnea, by contrast, is a partial collapse of the airway, resulting in shallow breathing. For a hypopnea to be considered an event, airflow typically decreases by at least 30% for a minimum of 10 seconds, often accompanied by a drop in blood oxygen levels. Both apneas and hypopneas disrupt sleep and can lead to lower blood oxygen levels.
Measuring Sleep Disordered Breathing
To quantify these breathing disruptions, healthcare professionals use the Apnea-Hypopnea Index, or AHI. The AHI represents the average number of apneas and hypopneas a person experiences per hour of sleep. It is calculated by adding the total number of apnea and hypopnea events recorded during a sleep study and then dividing that sum by the total hours of sleep.
The AHI is primarily collected during a sleep study, also known as a polysomnogram. These studies can be conducted overnight in a specialized sleep laboratory, or sometimes a simplified version can be performed at home. The AHI is a tool used by doctors to diagnose sleep apnea and determine its severity.
Defining Severity Levels
While occasional, brief breathing irregularities can occur, an AHI of fewer than five events per hour is generally considered normal for adults, indicating that sleep apnea is not present within this range. This minimal level accounts for brief breathing interruptions in healthy individuals.
Sleep apnea is categorized into different severity levels based on the AHI. Mild sleep apnea is diagnosed when the AHI ranges from 5 to fewer than 15 events per hour. Moderate sleep apnea falls within an AHI of 15 to fewer than 30 events per hour. Severe sleep apnea is indicated by an AHI of 30 or more events per hour. Even a mild diagnosis may warrant attention, especially if accompanied by other symptoms or health concerns.
When to Seek Medical Advice
If you suspect sleep apnea, seeking medical advice is important. Common symptoms include loud snoring, particularly if interrupted by periods of quiet or gasping for air. Others might notice observed breathing pauses during sleep.
Daytime fatigue, excessive sleepiness even after a full night’s rest, morning headaches, and difficulty concentrating are also frequent indicators. A healthcare provider will typically begin with a physical exam and inquire about your symptoms and medical history. If sleep apnea is suspected, a sleep study will likely be recommended to accurately diagnose the condition and determine its severity.