Table of ContentsView AllTable of ContentsApnea-Hypopnea IndexResultsOther TestsTreatmentFrequently Asked Questions
Table of ContentsView All
View All
Table of Contents
Apnea-Hypopnea Index
Results
Other Tests
Treatment
Frequently Asked Questions
Sleep apneais asleep disorderthat causes breathing difficulties during sleep.The condition ranges in severity from a mild decrease in airflow to airflow completely stopping, which can be life-threatening.
Sleep apnea has multiple causes, including the tongue or tissues in the airways blocking the air or challenges related to the signals sent from the brain to control breathing during sleep.
Theapnea-hypopnea index(AHI) is a scale to measure the symptoms of sleep apnea. It is used with sleep testing to diagnose the condition and determine how severe it is.
Learn more aboutsleep apnea, the apnea-hypopnea index, other tests for sleep apnea, and treatment options.
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What Is the Apnea-Hypopnea Index?
The apnea-hypopnea index (AHI) measures how many times per hour, on average, a person partially or fully stops breathing during sleep. AHI is measured during a sleep study, anovernight testused to diagnose sleep apnea and other sleep disorders.
A pause in breathing must last 10 seconds or more to be counted. Apnea is when breathing is reduced to 10% of normal or less, including when breathing completely stops.Hypopnea is when breathing is reduced to 70% or less.
Respiratory Event Index (REI) is a measure that is sometimes used instead of the AHI in sleep testing that is done at home. It includes all the apnea and hypopnea events during the sleep study, not just the events that happen while the person is sleeping.
Interpreting AHI Results
A lower AHI number means fewer episodes of breathing difficulty. Here are the AHI score ranges and what they mean:
The AHI is not necessarily an accurate way to measure the severity of sleep apnea because it does not differentiate between apneas and hypopneas, or how much the airflow is reduced.
Other Sleep Apnea Tests
AHI alone is not enough to diagnose sleep apnea or show the severity of the condition.It is just one of the measures that are assessed during a sleep study (an overnight test used to diagnose sleep apnea and other sleep disorders).
Two other measures used are the respiratory disturbance index (RDI) and theoxygen desaturation index(ODI). In addition to AHI, RDI, and ODI, the symptoms of sleep apnea and how a patient feels are also considered.
Respiratory Disturbance Index (RDI)
The respiratory disturbance index (RDI) is similar to the AHI because it includes both apneas and hypopneas. Unlike the AHI, the RDI also includes the number of times per hour a person is awakened or shifts to a more awakestage of sleepbecause they are having breathing difficulties.
This makes RDI a more sensitive measure of assessing breathing difficulties during sleep.
Oxygen Desaturation Index (ODI)
One role of blood cells is to carry oxygen to organs, which is required to live.Oxygen desaturation is when there is a decrease inoxygen in the blood.
The oxygen desaturation index (ODI) measures oxygen desaturation during sleep. This measure is important because oxygen desaturation during sleep is linked to an increased risk of sleep apnea complications such asheart conditions.
Sleep apnea is treatable. The most common treatment for sleep apnea is positive airway pressure ( PAP) which uses a machine to push air into the lungs through the nose or through the mouth and nose together.
Other sleep apnea treatment options aresurgery,devicesthat go in the mouth, andweight loss.
CPAP
Continuous positive airway pressure (CPAP) is a type of PAP treatment for sleep apnea. It uses a device that pushes air into the lungs through the nose and mouth together at the same pressure level for the entire night.
The machine is connected to a hose that is attached to the face with either a mask that covers the nose and mouth or a smaller piece that sits at the openings of the nose.
BiPAP
Bi-level positive airway pressure (BiPAP) is a type of PAP treatment for sleep apnea. The treatment involves a device that pushes air into the lungs through the nose or through the mouth and nose together at different pressure levels during the night.
The pressure increases when the person inhales and decreases when the person exhales to allow for more breathing support when needed without such a high pressure when it is not needed.This is important because some people who are unable to tolerateCPAPare able to useBiPAP.
ASV
Adaptive servo-ventilation (ASV) is a type of PAP treatment for sleep apnea. The treatment involves a device that pushes air into the lungs through the nose or through the mouth and nose together at different pressure levels during the night. Unlike BiPAP, ASV measures the breathing of the person and automatically changes the pressure setting to respond to changes in breathing.
For example, when the machine detects that a person is struggling to breathe, the air pressure will increase. This option might be best for people who are likely to experience changes in the pressure settings they need in a short time, such as pregnant people or people who are losing weight.
ASV is also used for people who have more complicated cases with multiple types of sleep apnea and people who do not respond well to other PAP options.
Lifestyle Changes
In addition to PAP devices, there are other ways to treat sleep apnea, including lifestyle changes. Since being overweight can block airways and lead to sleep apnea, weight loss can be used as a treatment either instead of or along with other options.
Lifestyle changes to improve sleep apnea include:
Summary
Sleep apnea is a sleep disorder that causes difficulty breathing during sleep. The apnea-hypopnea index (AHI) is a number that is used to diagnose sleep apnea and determine the severity of the condition. It measures the average number of breathing difficulty events per hour of sleep.
However, AHI cannot be used alone. Other measures are also used along with assessing the symptoms each person experiences. In general, an AHI of less than five is considered to be normal, five to 15 is considered mild sleep apnea, 15 to 30 is considered moderate sleep apnea, and 30 or above is considered severe sleep apnea.
However, it’s important to know the measure is just a guideline. The scores represent the average number of events per hour, not how restricted the airflow might be during those events.
A Word From Verywell
Living with sleep apnea can be challenging, especially when the symptoms are severe enough to interfere with your nightly sleep or affect your daily life. Treatment options are available, including devices to help with breathing and lifestyle changes.
If you or someone you know is dealing with sleep apnea, you can get treatment. Reach out to your healthcare provider or a specialist like a neurologist or a pulmonologist specializing in sleep medicine for support.
The apnea-hypopnea index (AHI) measures the number of times a person experiences difficulty breathing each hour of sleep, on average. An AHI of less than five is considered normal and no sleep apnea. An AHI of five to 15 is considered mild sleep apnea.However, the number alone cannot show the severity of sleep apnea because it does not show how much the air is blocked (e.g., partially or fully).
The apnea-hypopnea index (AHI) measures the number of times a person experiences difficulty breathing each hour of sleep, on average. An AHI of less than five is considered normal and no sleep apnea. An AHI of five to 15 is considered mild sleep apnea.
However, the number alone cannot show the severity of sleep apnea because it does not show how much the air is blocked (e.g., partially or fully).
The side effects of sleep apnea include dry mouth, headache in the morning, sleepiness throughout the day, and high blood pressure. In more severe cases, sleep apnea can be life-threatening. It is important to seek medical care if you think you may have sleep apnea.
17 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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