In order to diagnose and treat sleep apnea, a sleep study is often necessary. This article will explain the key factors of a sleep apnea test result, including your Apnea Hypopnea Index (AHI), types of sleep disruptions, your sleep stages, and your oxygen desaturation (SaO2) levels.
Your Apnea Hypopnea Index (AHI)
The Apnea Hypopnea Index (AHI) is a key metric used to measure the severity of sleep apnea. It is calculated by dividing the total number of apneas and hypopneas (partial breathing interruptions) that occur during sleep by the total number of hours of sleep. The resulting number represents the average number of apneas and hypopneas that occur per hour of sleep. Your AHI score is used to categorize the severity of your sleep apnea as follows:
Mild sleep apnea: AHI score of 5 to 14 events per hour
Moderate sleep apnea: AHI score of 15 to 29 events per hour
Severe sleep apnea: AHI score of 30 or more events per hour
Types of Sleep Disruptions
There are two primary types of sleep disruptions associated with sleep apnea: apneas and hypopneas. Apneas are defined as pauses in breathing that last for at least 10 seconds. Hypopneas are defined as partial breathing interruptions that lead to a decrease in airflow of at least 30% for at least 10 seconds. Both apneas and hypopneas can result in a decrease in oxygen levels in the blood, which can have serious health consequences over time. Your sleep study report may provide information about the number and severity of these events.
Your Sleep Stages
During a sleep study, your sleep stages are monitored in order to assess the quality and duration of each stage of sleep. There are four primary stages of sleep, which are divided into two categories: Non-REM (NREM) sleep and REM sleep. NREM sleep is divided into three stages, with stage 1 being the lightest stage of sleep and stage 3 being the deepest. During NREM sleep, the body repairs and regenerates tissues, builds bone and muscle, and strengthens the immune system. REM sleep, or rapid eye movement sleep, is the stage of sleep in which dreaming occurs. During REM sleep, the brain is highly active, and the body is essentially paralyzed, with the exception of the eyes and diaphragm muscles. Your sleep study report may provide information about the percentage of time spent in each stage of sleep.
Your Oxygen Desaturation (SaO2) Levels
During a sleep study, your oxygen desaturation levels are monitored in order to assess the severity of sleep apnea. Oxygen desaturation is the term used to describe a decrease in the level of oxygen in the blood. This can occur as a result of apneas and hypopneas, which can lead to a decrease in airflow and a subsequent decrease in oxygen levels. Oxygen desaturation levels are typically reported as the percentage of time spent with oxygen saturation levels below a certain threshold (e.g. 90%). Your sleep study report may provide information about the severity and duration of your oxygen desaturation events.
In conclusion, a sleep study is an important tool in the diagnosis and treatment of sleep apnea. Your Apnea Hypopnea Index (AHI), types of sleep disruptions, your sleep stages, and your oxygen desaturation (SaO2) levels are all key factors that can be used to assess the severity