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Apnea Hypopnea Index

What is Apnea Hypopnea Index (AHI)

Obstructive sleep apnea is a common sleep disorder that affects one in every five adults – about 20% of the population – in the United States alone. People with sleep apnea experience complete or partial airway obstruction, resulting in symptoms such as choking, gasping, loud snoring, and daytime drowsiness.

According to estimates, more than 75% of severe sleep apnea cases go undiagnosed. You can get yourself tested by consulting a sleep medicine doctor or undertake insomnia treatment online by sitting for an at home sleep study. You can also consult a sleep medicine doctor to get a home sleep apnea test. 

Consultations with sleep apnea specialists or sleep studies usually include apnea-hypopnea index (AHI) readings. What is AHI, and how does it help diagnose obstructive sleep apnea? Let’s look into it. 

What is the Apnea-Hypopnea Index (AHI)?

The apnea-hypopnea index (AHI) is a common diagnostic tool that allows sleep medicine doctors to calculate the presence and stage of obstructive sleep apnea. AHI measures the average number of hypopneas and apneas a patient experiences in each hour of sleep. 

Sleep specialists and doctors calculate it by dividing the total number of hypopneic and apneic events by the total number of hours a patient was asleep. A hypopnea or apnea must be at least ten seconds long to be included in the calculation. 

It is common for doctors to calculate AHI during a sleep study – also known as a polysomnogram. A polysomnogram keeps an account of an individual’s blood oxygen levels, brain waves, breathing, and heart rate while sleeping.

Although sleep studies generally take place in specialized laboratories, you can also undertake an at home sleep study in a simplified version.

Although AHI is the basic tool doctors use to diagnose obstructive sleep apnea, your sleep specialist may use other metrics to accurately determine the severity of your condition. Some of these metrics are as follows:

Related: Home Remedies For Sleep Apnea

Oxygen Desaturation Index (ODI)

The Oxygen Desaturation Index determines the average frequency of instances when an individual’s blood oxygen levels fall below the average threshold for ten seconds or more in each hour. 

Level of Carbon dioxide In Blood 

The level of carbon dioxide in the blood is another crucial metric, especially for children. An increase in carbon dioxide concentration may occur due to extended breathing periods at less than total capacity, which may occur even if the airways are partially blocked. 


Dissecting Apnea-Hypopnea Index for Children and Adults 

The Apnea-Hypopnea Index is measured on a numeric scale. Adult scores are categorized into three domains corresponding to the severity of obstructive sleep apnea. These three categories are as follows: 

Related: Florida Sleep Specialists


An AHI of a minimum of five events every hour but less than 15. 


An AHI of a minimum of 15 events per hour but less than 30. 


An AHI of a minimum of 30 events per hour. 

Although a minimum of five episodes is the cutoff for adults, even a single episode is enough to diagnose obstructive sleep apnea in children. 

Children have a smaller lung capacity and faster metabolism than adults and thus breathe faster. That is why even a single apneic event can considerably impact a child. 

OSU diagnosing categories are not as standardized for children as they are for adults, but most sleep specialists divide childhood sleep apnea into the following three categories: 

Related: Is 6 hours of sleep enough


Children with an AHI of a minimum of one and a maximum of five events per hour may be diagnosed with mild sleep apnea. 


An AHI of a minimum of six and a maximum of ten events per hour may indicate moderate sleep apnea in children. 


An AHI of more than ten events per hour may hint at severe sleep apnea in children. 

Sleep apnea specialists diagnose adolescents with either the adult or child scale.

Related: How Much Does A Sleep Study Cost Without Insurance?

Sleep Apnea AHI Chart for Children and Adults 

Severity  Pediatric AHI  Adult AHI 
Mild Obstructive Sleep Apnea  Minimum 1 and maximum 5 events per hour Minimum 5 and maximum 15 per hour 
Moderate Obstructive Sleep Apnea Minimum 5 and maximum 10 events per hour  Minimum 15 and maximum 30 events per hour 
Severe Obstructive Sleep Apnea More than 10 events per hour  More than 30 events per hour 

What Happens if You Get Diagnosed With a Moderate or Severe AHI Score?

Individuals who get a moderate or severe AHI score may need to use a Continuous Positive Airway Pressure (CPAP) machine while sleeping. A CPAP machine is worn over the nose and is attached to a machine supporting a hose.

The machine blows air into your nose, preventing you from waking up repeatedly during the night. It can also keep a score of your AHI. 

If you have a moderate to high AHI score, you may also have to change your lifestyle to help you cope with the severity of your obstructive sleep apnea.

These changes may include sleeping on your stomach or sides instead of your back, losing weight, following a healthy diet and exercise regime, and quitting smoking. 

If you are looking to get a consultation from a sleep apnea specialist or consult doctor online, SleepRx is the place for you.

American-board certified and fellowship-trained professionals at SleepRx offer high-quality sleep services right at your doorstep! Head over to SleepRx to book an online appointment within minutes and sit for an at home sleep study!


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