Is Hypopnea Dangerous?

Many people are unaware that hypopnea is a type of sleep apnea, though the condition itself is different from apnea itself. It is common for people to experience both conditions over the course of the night, however, so it can be helpful to understand the difference between the two. Read on to learn more about apnea vs. hypopnea, and what you should do if you suspect you have one or both of these conditions.   

Apnea vs. Hypopnea

Apnea and hypopnea are related, and though hypopnea is a type of sleep apnea, apnea and hypopnea mean different things. Hypopnea can be defined as abnormally slow or shallow breathing. It is distinct from apnea, in which there is a total cessation of breathing. While apnea occurs when airflow from your lungs is completely blocked by an obstruction from your throat, hypopnea occurs when the airway is only partially blocked and airflow from your lungs is reduced for at least 10 seconds. 

Sleep apnea and hypopnea often occur together and share similar symptoms.[1] That said, there are different types of hypopnea and different types of sleep apnea, meaning there are differing causes and states when each condition occurs. Let’s take a look at the different types of this condition for a better understanding of how they can affect you.

Types of Hypopnea[2]

• Central hypopnea: This is when both your airflow and your breathing effort are reduced due to your brain failing to send the signal to breathe to your muscles.
• Obstructive hypopnea: This is when your airflow is reduced, but your breathing effort is not impacted. 
• Mixed hypopnea: This is when you experience a mixture of both types of hypopnea. 

Types of Sleep Apnea[3]

• Central sleep apnea: This is when your brain fails to send the signal to your muscles to breathe, so the muscular effort to breathe does not take place.
• Obstructive sleep apnea: This is when your airway is blocked, so while the brain does send the signal to breathe as normal, and your muscles respond correctly, you cannot get the airflow you need.
• Mixed sleep apnea: This is when you experience a mixture of both types of apnea. 

As you can see, the types of each condition are similar. However, it is important to distinguish that hypopnea is characterized by reduced breath and periods of overly shallow breathing, while with apnea, breathing stops all together. 

It is also helpful to be aware of what is called Cheyne-Stokes breathing, which is characterized by periods of increased breathing effort (hyperpnea), followed by decreases in both breathing effort and airflow. Toward the end of these repeating cycles of fast breathing followed by slow breathing, there is often a period of apnea at the end of the decreasing cycle. Typically, these cycles last around a minute and a half, and can occur when the person is awake or sleeping, though apnea is more of a concern during sleep.[2][3]

Causes of Hypopnea

Certain populations are more prone to developing hypopnea. Hypopnea is more common in men than in women, and it is more common in middle-aged and older adults than younger people. Finally, if your family has a history of hypopnea, you are more likely to develop it as well.

The causes of obstructive hypopnea are similar to those of sleep apnea and include:[4]

• Obesity
• Large tongue
• Narrow airway
• Nasal obstruction
• Large neck or collar size
• Drinking alcohol before going to sleep or taking sedatives or other drugs
• Excess tissue at the back of the throat (tongue, uvula, soft palate, enlarged tonsils and adenoids)

Central hypopnea and apnea are less common than obstructive hypopnea and apnea, and may be caused by a number of different conditions, including:[3]  

• Cheyne-Stokes breathing
• End-stage kidney disease
• Heart failure 
• High altitudes 
• Medications, including opioids
• Stroke
• Treatment response to CPAP for obstructive hypopnea and apnea

What Happens During Episodes of Hypopnea

In cases of obstructive hypopnea, when the throat muscles relax, the airway becomes partially blocked, causing breathing to be disrupted for up to 10 seconds at a time, many times a night. This lowers the oxygen level in your blood and causes a build-up of carbon dioxide. Once your brain senses your breathing has stopped or is impaired, it rouses you from sleep and summons you to take a breath. This cycle can repeat itself throughout the night causing you to snore very loudly and awaken snorting, choking or gasping for air. Oftentimes, you won’t remember the awakenings, but you may wake up in the morning with a headache, feeling fatigued and in a state of unrest.[1][4]

During episodes of central hypopnea, your body simply is not being told to breathe by your brain, so it does not breathe normally. Your breathing does not cease all together with hypopnea alone, but you are not breathing the way you should because your brain is not communicating properly with your respiratory system. Often, central hypopnea does involve periods of central apnea as well. Central hypopnea is often identified because it does not cause loud snoring like obstructive hypopnea.[5] However, regardless of whether you are experiencing obstructive hypopnea, central hypopnea or mixed hypopnea, you will experience the same symptoms of waking with a headache and feeling unusually tired because of low blood oxygen levels. Only a sleep specialist can help you identify for certain what type of hypopnea you are experiencing and whether you are experiencing apnea as well. 

Diagnosing Hypopnea

Like sleep apnea, hypopnea is diagnosed during a test called a polysomnography, better known as a sleep study. During the test, you’ll stay overnight in a sleep lab and be hooked up to machines that monitor your heart rate, breathing rate and level of oxygen in your blood. The test will count how many, if any, apneas and hypopneas you experience during the night. There are also take-home monitors available that you wear while you sleep that measure your heart rate and oxygen levels to help a doctor diagnose your hypopnea or apnea.[6] 

Your hypopneas and apneas will then be measured using the apnea-hypopnea index (AHI) to assess the severity of your hypopnea and/or sleep apnea. The AHI measures the severity of your hypopnea and apnea in the following way:[1]

• None or minimal: This is when you have fewer than five hypopnea or apnea events per hour
• Mild: This is when you have between five and fifteen events per hour
• Moderate: This is when you have between fifteen and thirty events per hour
• Severe: This is when you have more than thirty events per hour, meaning your sleep is profoundly and regularly affected

Symptoms of Hypopnea

The symptoms of hypopnea are similar to apnea and include:[4]

• Irritability
• Mood swings
• Frequent awakenings
• Insomnia
• Morning headaches
• Anxiety and depression
• Waking up feeling un-refreshed
• Impaired concentration and awareness
• Daytime drowsiness and fatigue
• Loud snoring
• Low energy

However, it is important to note that many people are not aware that they are suffering from this condition because it occurs while they sleep, so they often blame their symptoms on stress or other concerns. If you have a partner and they have observed that you snore frequently, have shallow breathing or have seemed to breathe unusually at night, make them aware of these symptoms so they can help you identify whether you should be screened. If you suspect hypopnea or apnea, it is recommended that you complete a sleep study, as hypopnea and apnea can have a negative impact on your health and may put you at risk for other health complications.[1]

Treatment for Hypopnea

What is hypopnea treatment like? Once you complete your sleep study, your doctor will review your sleep hypopnea results with you and ask about your hypopnea symptoms before discussing your treatment options. Mild to moderate cases often improve or are completely eliminated with over-the-counter medications, lifestyle changes and dental devices. In severe cases, continuous positive airway pressure (CPAP) can be used while you sleep to send air at a constant, continuous pressure to help keep the airway open. As a last result, or if there is a clear obstruction within the airway, surgery may be an option to treat specific cases of hypopnea that do not respond to any of the above methods.

Lifestyle Changes You Can Make That May Help

Dr. Clifton Hunt, founder of the Delaware Sleep Disorder Centers in Wilmington, Delaware, recommends the following tips if you think you may have hypopnea:^[3]

• Test yourself with an online screening test – Think you have sleep hypopnea? Take an online screening test like the Epworth Test to determine if you need to see your doctor or a sleep specialist.
• Shed some pounds — Obesity can cause and complicate hypopnea. If you are severely overweight or obese, and there is no genetic cause for your hypopnea, losing a significant amount of weight can eliminate your condition completely.
• Say no to alcohol and sedatives or sleep medication — Alcohol, sedatives and sleep medications can make your condition significantly worse. Alcohol is especially problematic for hypopnea if you consume alcoholic beverages before bedtime. When you are trying to ascertain what affects your hypopnea, it is best to abstain from all these substances. 
• Sleep in an alternate position — When you sleep on your back, gravity causes hypopnea to worsen during sleep as it can contribute to the blocking of your airway. Avoid lying on your back when you sleep and sleep on your side instead. Dr. Hunt also recommends elevating your head with pillows.
• Welcome medical options that may improve your condition – After being diagnosed with hypopnea, your doctor may recommend treatment with CPAP, a machine that will help keep your airways open during sleep. Some people find CPAP uncomfortable. Be sure to speak to your health care provider or respiratory therapist if you feel uncomfortable wearing CPAP. There are adjustments that can be made with the machine and the headset that may make you more comfortable.

Is hypopnea dangerous? It can be, but making lifestyle changes, working with your doctor on prevention and seeing a doctor or sleep specialist for screening as soon as possible will help, and may even resolve your hypopnea all together. While you may not always be able to eliminate your hypopnea, working with your doctor and following medical instructions regarding lifestyle changes and medical treatments will ensure you have a better chance of improving your hypopnea and symptoms.

If you have any questions about apnea or hypopnea, or believe you or a loved one may have undiagnosed hypopnea or apnea, speak to your primary care provider or a sleep specialist.

Frequently Asked Questions About Hypopnea

When should you be concerned about hypopnea?

Only your doctor can answer this question for you, but it will typically depend on your symptoms and your apnea-hypopnea index (AHI) severity score. If you have a partner and they report that your breathing stops or slows regularly, you should see your doctor to be screened. Your AHI will be measured by your doctor, following a screening, and scored as follows:[1]

• None/minimal: When you have fewer than five hypopnea or apnea events per hour
• Mild: When you have between five and fifteen events per hour
• Moderate: When you have between fifteen and thirty events per hour
• Severe: When you have more than thirty events per hour, causing your sleep to be profoundly and regularly affected

Additionally, if you know you have hypopnea, but feel your current interventions are not successfully treating it or your symptoms, talk to your doctor about adjusting your treatment. 

When should you talk to your doctor about hypopnea?

Generally speaking, if you have the symptoms of hypopnea or apnea, or if your partner tells you that your breathing appears to be interrupted when you sleep, it is a good idea to talk to your doctor about a sleep screening. Hypopnea and apnea can leave you dangerously exhausted, and there are other health complications that can occur if your condition goes untreated. Over time, untreated hypopnea and apnea can affect your mood and focus, but they can also negatively impact your blood pressure, cardiovascular health, insulin and glucose management, and they can cause weight gain and other symptoms resulting from low blood oxygen. If you suspect that you are experiencing hypopnea or apnea, talk to your doctor sooner rather than later.[6] 

Sources

[1] Galan, Nicole. “Hypopnea: Causes, Types, and Treatments.” Medical News Today, MediLexicon International, 18 Oct. 2017, www.medicalnewstoday.com/articles/319378#types-of-hypopnea.

[2] Nabili, Siamak N. “Obstructive Sleep Apnea Causes, Test, Treatment & Machine.” MedicineNet, MedicineNet, 5 Sept. 2018, www.medicinenet.com/sleep_apnea/article.htm#sleep_apnea_facts.

[3] “Central Sleep Apnea.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 25 June 2019, www.mayoclinic.org/diseases-conditions/central-sleep-apnea/symptoms-causes/syc-20352109.

[4] Wells, Diana K. “Everything You Should Know About Hypopnea.” Healthline, Healthline, 20 Apr. 2017, www.healthline.com/health/hypopnea.

[5] Asp, Kevin. “Obstructive vs. Central Sleep Apnea: Key Differences and Treatment Options.” American Association of Sleep Technologists, American Association of Sleep Technologists, 18 Sept. 2017, www.aastweb.org/blog/obstructive-vs.-central-sleep-apnea-key-differences-and-treatment-options.

[6] “Obstructive Sleep Apnea.” Columbia University Department of Neurology, Columbia University Medical Center || NewYork-Presbyterian Hospital, 2015, www.columbianeurology.org/neurology/staywell/document.php?id=42067.

[7] Quinn, Holly. “Expert Tips For Battling Hypopnea Syndrome.” HuffPost, HuffPost, 22 Feb. 2012, www.huffpost.com/entry/hypopnea-syndrome-tips_n_1167942.