What Is Hypopnea?

The information in this article is for educational purposes only and should not be considered medical advice. [Read our full health disclaimer]

Updated on September 24, 2023

Hypopnea is a sleep breathing disorder that causes episodes of shallow breathing, known as hypopneas, while you’re asleep. This limited breathing can lead to oxygen desaturation, and if you leave it untreated, it can become a risk factor for different medical conditions such as diabetes and cardiovascular disease.

Obstructive sleep apnea, a.k.a. OSA, and hypopnea are closely connected, and the two sleep disorders have similar risk factors, complications, and symptoms. The biggest difference between the two is that you stop breathing completely during a sleep apnea episode rather than breathing slowly as you do during a hypopnea occurrence.

Although hypopnea is a very serious chronic sleep disorder, there are effective treatment options. Learning as much as possible about hypopnea’s symptoms, causes, and effects can make it easy to notice and help you find the best treatment option for your case of hypopnea.

The Truth: What Is Hypopnea?

In fact, hypopnea is both the common name and a symptom of a type of sleep breathing disorder. We can define hypopnea as more than ten seconds of shallow breathing while you’re asleep, during which you can lose up to 90% of your normal airflow and the oxygen saturation of your blood can decrease by 3% to 4%. In some cases, it can be followed by fragmentation of your night sleep. The longer the hypopnea episode lasts, the worse the effect it has.

If you have more than five hypopnea episodes per one hour of sleep, you most likely suffer from a hypopnea sleep disorder. Additionally, you can experience symptoms such as mood disturbances and excessive sleepiness during the daytime. Moreover, untreated hypopnea might increase the chances of stroke, heart attack, heart disease, liver fibrosis, and diabetes.

Difference Between Hypopnea and Obstructive Sleep Apnea

As previously mentioned, hypopnea and obstructive sleep apnea are in fact different versions of the same sleep breathing disorder. Obstructive sleep apnea is a total blockage of the airways, while hypopnea is just a partial blockage of the airways. There are some cases when they occur together.

Hypopnea was discovered when the healthcare professionals noticed that obstructive sleep apnea patients didn’t always experience a total blockage of the airways while they were asleep. Instead of being just a total periodic blockage, it was either just partial blockage or a combination of both partial (hypopnea) and complete (sleep apnea).

In almost all cases, you’ll have both sleep hypopnea and sleep apnea. If, for the time being, you’re experiencing just hypopnea, there is a good chance for you to develop sleep apnea as well.

Apnea Hypopnea Index (AHI)

The Apnea Hypopnea Index, a.k.a. AHI, refers to the number of apneas or hypopneas you have per hour of sleep. By using AHI, your doctor can determine the severity level of the hypopnea according to the following:

  • None or minimal. If you experience less than 5 hypopneas or apneas by an hour;
  • Mild. When you experience from 5 to 15 hypopneas or apneas by an hour;
  • Moderate. When you experience from 15 to 30 hypopneas or apneas by an hour;
  • Severe. When you experience over 30 hypopneas or apneas by an hour;

Your doctor can use the Respiratory Disturbance Index, aka RDI, in order to determine the right treatment option. This Respiratory Disturbance Index includes more breathing irregularities, not only hypopneas or apneas. In some cases, your RDI might be higher than your AHI.

Types of Hypopnea

Generally, there are three main types of hypopnea. They all have similar symptoms, but each type of hypopnea has different causes and might need different treatment options. However, it can be hard for your doctor to determine the type of hypopnea.

  • Obstructive hypopnea. This type of hypopnea, also known as obstructive sleep apnea hypopnea syndrome (OSAHS) happens as a result of a partial blockage in the upper airways. When you’re asleep, the tissue and muscles in your throat relax naturally. So, if you suffer from OSAHS, the relaxed tissue and muscle will cause narrowing in your throat, which in turn decreases airflow.
  • Central hypopnea. This type of hypopnea is caused by decreased breathing, also known as bradypnea (abnormal slow breathing rate), rather than decreased airflow. In fact, central hypopnea or central sleep apnea occurs as a result of disrupted respiratory effort, i.e. difficulties during breathing. Central hypopnea can occur as a result of side effects from medications and problems with the brainstem.
  • Mixed hypopnea. This type of hypopnea happens when hypopnea events are caused by both decreased breathing and airflow. Despite being classified separately, mixed hypopnea is mainly considered as a part of obstructive sleep apnea hypopnea syndrome and usually happens in persons that have a severe case of OSAHS.

Causes of Hypopnea

Some causes of hypopnea can be extra kilograms/pounds of fat that’s built up in your neck, resulting in blocked airways. Other causes for hypopnea can be your age, gender, body structure, and maybe the most important one – genetics.

Smoking, drinking alcohol, or even some medications such as sedatives can cause you to experience hypopnea events. Kidney and heart diseases in advanced stages can cause your neck to build up with fluids, making you breathe more difficult and experience hypopnea events.

Obstructive sleep apnea can be a cause for you to have hypopnea, due to the relations and similarities between them.

Symptoms of Hypopnea

Hypopnea can reduce your nighttime breathing by a third or even more, meaning your body gets less oxygen than normal. This can result in the following symptoms:

  • Feeling unusually sleepy during daytime;
  • Loud snoring and waking up from sleep breathless or with an intensive headache;
  • Lack of energy during daytime;
  • Having trouble memorizing things or concentrating;
  • Feeling irritable or depressed;
  • Choking while you’re asleep;
  • Chronic nose congestion;
  • Gaining weight;
  • Fatigue;
  • Sexual dysfunction.

Many people don’t even know that they have this sleep disorder because excessive daytime sleepiness is usually associated with work, family responsibility, or stress.

If you have hypopnea, you might disturb your partner’s sleep as well because of the symptoms (such as choking and loud snoring). However, this might be very helpful in diagnosing hypopnea because your partner will explain to the healthcare professional what is really happening when you’re experiencing a hypopnea episode because in some cases you’re not even aware that you suffer from hypopnea.

How Is Hypopnea Diagnosed?

The first thing that a healthcare professional will ask is about your family and medical history. Afterward, they’ll check out your tonsils, upper airway, and weight. Your doctor will order ultrasound imaging and blood tests so they can rule out other medical conditions that can cause your symptoms.

The healthcare professional can suggest a sleep study, also known as polysomnography. They attach you to sensors that count how many times your breathing stops or slows down per hour while you’re asleep. It also measures your blood oxygen levels, brain waves, heart rate, and other vital signs. This sleep study occurs in specialized clinics, however, you can use at-home monitors instead.

Healthcare professionals will match the results from the sleep study against the Apnea Hypopnea Index and determine whether you have hypopnea and the severity level. 

Risk Factors

It’s not unusual to have either sleep hypopnea or obstructive sleep apnea, however, there are particular factors that can increase your risk. Here are some of the most common risk factors for sleep hypopnea:

  • Gender. Men experience sleep hypopnea more than women;
  • Age. People between the ages of 40 and 65 are under a higher risk of developing sleep hypopnea;
  • Obesity. Many people that experience hypopnea are either overweight or obese;
  • Medical conditions. Some medical conditions such as diabetes, hypothyroidism, enlarged tonsils or adenoids, heart failure, etc., are risk factors for hypopnea;
  • Smoking. If you’re a smoker, your chances of developing hypopnea are much higher;
  • Family history. If you have a family member who suffers from hypopnea, you have a higher chance to develop hypopnea;
  • Some narcotics and sedatives. If you’re taking medications, this can also put you at risk of developing sleep hypopnea.

While some of the risk factors cannot be altered, there is plenty that you can eliminate from your life in order to reduce your risk of ever getting an issue with hypopnea. You can make some lifestyle changes, such as losing weight, quitting smoking and drinking alcohol, avoiding sedatives, and exercising.

Treatment Options

Healthcare professionals usually treat hypopnea by combining continuous positive airway pressure therapy, aka CPAP, and some lifestyle changes. These lifestyle changes can include quitting smoking and drinking alcohol, managing your weight, and altering your sleeping position. Weight loss is one of the most remarkable lifestyle changes that you can make because a weight loss of 10% is linked with a 26% improvement in symptoms.

CPAP therapy is the best treatment option for obstructive hypopnea and it’s done by using CPAP machines. This machine delivers pressurized air through a mask and hose while you’re asleep, holding your airways open and at the same time decreasing hypopneas or even preventing them from happening. Successful CPAP therapy can have an immensely positive effect on your quality of life, as well as decrease hypertension and the risk of cardiovascular disease.

You have to be aware that untreated sleep hypopnea can lead to other medical conditions, including, strokes, high blood pressure, and accidents from drowsiness.

Concluding Thoughts

Hypopnea itself isn’t dangerous or life-threatening. The time periods of decreased breathing are short, and your brain is quite good at restarting your breathing patterns. However, hypopnea can cause many serious medical problems over a period of time if it’s not properly treated. If you experience some of the symptoms of hypopnea or obstructive sleep apnea you should seek medical advice from a healthcare professional and don’t leave it untreated in any case.

Bree Taylor - Lead Editor

Lead Editor

Bree is an interior designer with a passion for helping people improve their sleep quality.

She specializes in creating comfortable and functional bedroom spaces that promote a good night’s rest.

When she’s not testing mattresses or helping people get the best rest possible, Bree loves to travel and explore new cultures.

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