When a partial blockage of the airway happens, it is a condition known as hypopnea, which is a feature of obstructive sleep apnea hypopnea syndrome. Obstructive sleep apnea hypopnea syndrome is a disease in which the airway is blocked to differing degrees while a person is asleep. On the other hand, sleep apnea is a full obstruction of the airway during sleep.

When a person experiences episodes of hypopnea, there is a 10-second period when their breathing is reduced by 50 percent or more. Both conditions, hypopnea and sleep apnea are severe medical conditions which can trigger a number of other health issues. As we have discussed sleep apnea a number of times, let’s now take a closer look at hypopnea and everything there is to know about the condition.

Hypopnea Causes

The major risk factors for this condition are smoking and obesity. Hypopnea occurs when there is a narrowing of the airways leading to the lungs during sleep. As a result, the muscles in the back of the throat relax and the airway narrows and collapses. Hence, the person who experiences such episodes doesn’t have normal and regular breathing. This disrupted breath can last up to 30 seconds at a time to people both with hypopnea and sleep apnea.

When such episodes happen, the body and the brain don’t get the necessary oxygen and consequently, the brain wakes up and starts breathing again. However, these awake instances are so short that a person doesn’t even remember that they’ve happened.

Symptoms of Hypopnea

There are a number of symptoms which are associated with hypopnea. In fact, the symptoms of hypopnea are similar to those of obstructive sleep apnea. Hence, some of the most common hypopnea symptoms include insomnia, mood changes, excessive daytime sleepiness, fatigues, difficulty with memory and concentration, and waking at night and feeling short of breath.

Types of Hypopnea

There are three different types of hypopnea, including central, obstructive and mixed hypopnea. In central hypopnea, both airflow and breathing effort are reduced, while at obstructive hypopnea, only the flow of air is reduced, rather than the breathing effort. In mixed hypopnea, a person experiences a mix of both central and obstructive hypopnea episodes. People with central hypopnea don’t have any of the signs of obstruction, such as blocked airway or snoring.

Hypopnea vs. Sleep Apnea

These two conditions are, in fact, very similar. Unsurprisingly, hypopnea is a type of sleep apnea. Hypopnea refers to abnormally slow or shallow breathing, while sleep apnea means periods of no breathing. The major difference between these two conditions is in the degree of blockage in a person's airway.

Therefore, a person who has sleep apnea experiences a completely blocked airway, while a person with hypopnea deals with only a partially blocked airway. These two conditions can occur together and it’s often the case that a person who has sleep apnea also has episodes of hypopnea and vice versa.

Apnea Hypopnea Index (AHI)

The Apnea Hypopnea Index (AHI) is the number of apneas or hypopneas a person experiences per hour of sleep. The AHI is a clear indicator of the severity of hypopnea. So, if a person experiences less than 5 events per hour, it is a minimal severity, a mild severity means that there are between 5 and 15 events per hour, moderate severity of hypopnea is between 15 and 30 events per hour, while a severe hypopnea means that a person experiences more than 30 events per hour. Thus, the Respiratory Disturbance Index (RDI) might be used to determine the best treatment plan.

Hypopnea Treatment

One of the best and most possible treatments for hypopnea is the use of a CPAP machine. However, the treatment will always depend on the severity of hypopnea. The goal of the treatment will be to eliminate the obstruction in the airway in order to make breathing easier and more seamless. Some of the other possible treatments might include the use of a device to stabilize and open the airway and surgical removal of excess tissue.

However, there are also a number of things a person can do on their own in order to manage or prevent a hypopnea episode. Thus, a person should quit smoking, shed extra pounds, avoid alcohol, sedatives, and sleep medications.

So, if you are experiencing excessive daytime sleepiness, you should discuss this with your doctor.