Understanding Your Sleep Apnea Study Results

What Do the Sleep Apnea Study Numbers Mean?

The information gathered during your sleep study—either a home study (HST) or an in-lab study (PSG)—is used to determine your problem and its severity of it. And, while the numbers do tell your doctor a lot, there’s more to help you than JUST the numbers.

During the study, the number of times you stop breathing(apnea)or breath too shallowly(hypopnea) is recorded. Reduction in the level of oxygen(oxygen desaturation)in your blood is also noted. This information is used to classify the presence and severity of obstructive sleep apnea (OSA).

Types of airway obstructions:

  • Apnea—a complete collapse of the airway, breathing stops for 10 seconds or more, and airflow to the lungs is blocked.
  • Hypopnea—a partial collapse of the airway, breathing is reduced for 10 seconds or more, and airflow to the lungs is restricted.

The Apnea Hypopnea Index (AHI)is the number of apneas and hypopneas per hour of sleep. It is calculated by adding the apneas and hypopneas together and then dividing that number by the number of hours you slept, like this:

AHI= Apneas + Hypopneas
​Total hours of sleep

Once you have your AHI you can use this table to Classify your OSA severity:

AHISeverity of OSA
5-15Mild OSA
15-30Moderate OSA
>30Severe OSA
OSA severity

Your sleep study results may also include another number called the Respiratory Disturbance Index (RDI). This number includes apneas, hypopneas, and other additional breathing irregularities. So, the RDI is often higher than the AHI.

When having episodes of apnea or hypopnea during OSA, the level of oxygen in your blood may fall, depriving your body of much-needed oxygen. This is known as oxygen desaturation and is another number you will find in your sleep study.

At sea level, normal blood oxygen saturation is usually around 96-97%. During sleep, desaturation to 90% is generally considered mild, dips to 80-89% moderate, and below 80% severe.

The Oxygen Desaturation Index (ODI)is another index on your sleep study report. This index is measured by the number of times per hour that the oxygen level in your blood drops by a certain percentage from your baseline number. The American Academy of Sleep Medicine (AASM) counts a 3% drop as desaturation and Medicare uses a 4% drop.

Once you have your sleep study results, you and your doctor can review them and then based on the presence, and severity of the disease and individual factors can determine the best course of treatment for you.


Understanding your numbers is important, but they are only one part of the complex puzzle making up your sleep. The treatment decision that YOU and your doctor will make should take into account many different variables to help you achieve your ultimate goal of restful, refreshing and health-promoting sleep.


1. What is a sleep apnea study test?  

A sleep apnea study test is a diagnostic tool used to assess and diagnose sleep disorders, particularly sleep apnea. There are two types of sleep tests available: in-center polysomnography and home sleep tests. Polysomnography is conducted in a sleep center and requires an overnight stay. The test monitors the total sleep time, type of sleep (REM and non-REM), heart rate, blood oxygen level, and breathing patterns. A home sleep test is less comprehensive but is more convenient since the patient can sleep in their own bed. The test measures breathing patterns, oxygen levels, and heart rate. Sleep specialists use the results of the sleep apnea test to determine the severity of the sleep disorder and prescribe a suitable therapy, such as a continuous positive airway pressure (CPAP) machine, for severe sleep apnea.

2. What do test results mean?

The test results from an in-lab sleep study or home sleep apnea test are crucial in understanding one’s sleep health. These tests typically include measurements of various sleep stages, such as REM sleep and rapid eye movement, as well as sleep latency, which is the amount of time it takes for a person to fall asleep. A doctor or sleep specialist can interpret the test results to determine the presence, frequency, and severity of sleep apnea, whether it be obstructive sleep apnea or central sleep apnea. Understanding the results helps develop a plan for managing and treating sleep apnea, such as with continuous positive airway pressure (CPAP) therapy or other interventions. Overall, the test results provide valuable information that promotes better sleep health and improves quality of life.

3. How can I interpret my sleep apnea study test results?

Interpreting your sleep apnea study test results is crucial in determining the severity of your condition and choosing the appropriate treatment. Firstly, it is advisable to consult with a doctor or a sleep specialist who can explain the results of your sleep test, which is typically conducted in a sleep lab or through a home sleep study. The results of your sleep may indicate certain sleep disorders or reveal the type of sleep apnea you have, whether it’s obstructive sleep apnea or central sleep apnea. The sleep apnea severity is also determined by the number of apneas and hypopneas per hour of sleep. Depending on the type and severity of sleep apnea, treatment options may vary, such as continuous positive airway pressure (CPAP), dental sleep medicine, or lifestyle changes. It is essential to understand your sleep test results to ensure effective treatment and improve your overall health and quality of life.

4. How should I adjust my lifestyle based on my test results?

Based on your test results, you may need to adjust your lifestyle to improve your sleep quality. If you have sleep problems, such as sleep disruptions or sleep apnea, it’s important to work with a sleep technician to determine the best course of action. An overnight sleep study or home sleep apnea study may be needed to get an accurate baseline sleep study. Once you have a clear picture of your sleep patterns, you can make adjustments to your sleep position or behavior to improve your N2 sleep, the stage of sleep associated with memory consolidation and cognitive functioning. Additionally, your patient’s sleep may improve with more consistent sleep habits, such as going to bed and waking up at the same time each day. It may take some time to make changes, but with the guidance of a sleep technician, you can make positive adjustments to your sleep routine for better overall health.

5. How can I find additional information about understanding my sleep apnea study test results?

If you want to find additional information about understanding your sleep apnea study test results, there are several options available to you. One study may not provide all the answers, so it’s important to dig deeper. First, you can read and understand the report that was given to you by the sleep center. If you have specific questions or concerns, don’t hesitate to reach out to your doctor at BCOH. You can also research sleep apnea and the different stages of sleep, such as the deepest stage of sleep called REM sleep. Understanding how much of your sleep time was spent in REM sleep can help you understand why your sleep apnea is worse during certain times of the night. Additionally, 

6. How can I get help understanding my sleep apnea study test results?

If you’ve been diagnosed with sleep apnea, you most likely have already undergone a sleep study may to understand the severity of your condition. This test, also called a polysomnogram, monitors various factors related to sleep, such as brain activity, eye movement, heart rate, and breathing. The results of this sleep study may be difficult to interpret without professional guidance, especially if you’re unfamiliar with the different types of sleep studies available. Additionally, certain findings, such as experiencing worse symptoms during REM sleep or stopping breathing repeatedly during sleep, may indicate a more severe obstructive sleep apnea diagnosis. To get help with your sleep study test results, it’s best to schedule an appointment with a sleep physician or a specialist in sleep disorders. They can discuss the findings of your sleep study and explain any treatment options available to help manage your condition.

7. How often should I get my sleep apnea study test results checked?

Getting your sleep apnea study test results checked regularly is important to ensure that your treatment plan is working effectively. Your sleep doctor at BCOH will discuss the results with you in detail and make necessary adjustments to your treatment plan based on the severity of your sleep apnea. The frequency of follow-up tests depends on the form of sleep apnea you have and the levels of sleep disruptions you experience during the test. Some patients may need to get their results checked every few months, while others may only require an annual check-up. It is important to note that symptoms of sleep apnea can sometimes get worse during REM sleep, so regular monitoring is crucial in maintaining good sleep health. These tests are usually conducted in a sleep laboratory, where you will spend a night called sleep without qualifying, while sensors monitor your breathing and other bodily functions. Your sleep doctor will analyze the data collected during the test and recommend a treatment plan that works best for you.

8. What are the potential risks of sleep apnea?

Sleep is important for overall health and well-being. Sleep apnea is a sleep disorder that may cause potential risks to one’s health. It occurs when the muscles in the back of the throat fail to keep the airway open and can cause individuals to stop breathing for short periods of time while sleeping. This can cause disturbances in the degree of sleep, such as Rapid Eye Movement (REM) and wave sleep, leading to poor quality sleep. A study showed that individuals with sleep apnea may have a higher risk of cardiovascular disease, stroke, and hypertension due to the frequent disruptions in normal blood oxygen levels throut the night. Furthermore, sleep therapy is often required to manage the condition, and failure to treat it properly can lead to further health complications. Therefore, it is essential to seek specialized sleep care when experiencing symptoms of sleep apnea to reduce the potential risks and improve the overall quality of life.

9. How can I reduce the risk of developing sleep apnea?

There are several ways to reduce the risk of developing sleep apnea. One of the most effective methods is to maintain a healthy weight through regular exercise and a healthy diet. This is because excess weight can contribute to obstructive sleep apnea. Another way to reduce the risk of sleep apnea is to avoid smoking and limit alcohol consumption. Studies have also shown that getting enough sleep and ensuring a good sleep routine may help reduce the risk of sleep apnea. Additionally, it is important to pay attention to sleep stages, particularly rapid eye movement (REM) sleep, as it has been associated with a higher risk of breathing problems. Finally, it is recommended that individuals with a family history of sleep apnea get tested for the condition as it may run in families. Many sleep centers offer sleep studies to diagnose sleep apnea, which can help in its early detection and treatment.

10. What are the long-term consequences of not treating sleep apnea?

Sleep apnea is a serious sleep disorder that affects millions of people worldwide. If left untreated, the consequences of sleep apnea can be severe and long-lasting. People with sleep apnea may experience a range of symptoms, from snoring and fatigue to depression and anxiety. The long-term consequences of untreated sleep apnea can be even more serious. A study done on patients with untreated sleep apnea found that they were more likely to develop health problems such as heart disease, stroke, and diabetes. Additionally, sleep apnea is also associated with decreased cognitive function and memory impairment, which can have a significant impact on a person’s quality of life. Further, sleep apnea can lead to sleep fragmentation, which can disrupt rapid eye movement (REM) sleep, the stage of sleep where dreams occur. Therefore, it’s essential to seek treatment for sleep apnea to avoid its long-term consequences.

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