Most people have heard of hyperventilation or breathing too quickly and shallowly. Hypoventilation, which is less well known, is the exact opposite — a condition that leads people to breathe less than they should; it can be a cause, an indicator, or the result of another medical problem. Many different actions, conditions, and medications can cause hypoventilation, with treatment generally dependent on the cause.
What is Hypoventilation?
It is also known as respiratory depression. It happens when the body does not receive the amount of ventilation necessary to carry out the essential oxygen-carbon dioxide exchange — in other words, a person breathes too slowly and, therefore, ineffectively. The result is high levels of carbon dioxide in the body that can lead to severe medical emergencies.
Causes of Hypoventilation
There are multiple causes for hypoventilation, ranging from everyday, voluntary activities, to lifestyle choices, to medications. Voluntary breath-holding or intentionally underbreathing, for instance, can cause the condition (more on that later). Strokes and other medical conditions affecting the brain stem can lead to it as well, as can certain opioid medications. The most common cause is obesity; other medical causes include hypocapnia and chronic mountain sickness.
While hypoventilation is not a desirable condition for most people, for one physical training method, it is the goal. This type of training encourages intentional slow breathing alternated with breathing at a normal speed. This method is used in several different sports such as running, bicycling, rowing, skating, and swimming. It is said to delay fatigue and enable the person to perform better and more strenuously, but its use should be reserved for athletes in peak physical health — and even then only with caution.
Hypoventilation and Obesity
Obesity hypoventilation syndrome (OHS) is a medical condition that prevents a person from breathing quickly or deeply enough to continue the body’s internal processes. In some cases, the person may even stop breathing altogether. This occurs most often when one is sleeping and can lead to drowsiness during the day. OHS puts an enormous strain on the heart and can cause heart failure.
There are two stages of hypoventilation symptoms, the first being milder and including fatigue and daytime tiredness due to breathing less or not breathing at all for short periods during the night. The person may also feel short of breath and notice that he is breathing slowly and shallowly. Depression can also be concurrent with this condition, for two reasons: these secondary symptoms may initially develop because the person feels unwell much of the time, but can also stem directly from a lack of oxygen and important air-related nutrients.
Advanced Symptoms of Hypoventilation
As hypoventilation progresses, the level of carbon dioxide in the body increases. This leads to a new set of symptoms, many of which are much more serious. Some of these symptoms include headaches and confusion, seizures, and blue-tinted lips, toes, and fingers. This is the stage at which individuals most often notice the condition, and medical treatment is a must. While breathing quickly is not a symptom of hypoventilation, someone who is struggling may breathe faster as their body tries to get rid of the carbon dioxide it has built up.
Medical Conditions That Can Cause Hypoventilation
Aside from strokes and obesity, many other pre-existing medical conditions cause hypoventilation. Neuromuscular diseases, for instance, weaken the muscles that control one’s breathing and can lead to breathing less. Obstructive sleep apnea, even in a person of healthy weight, can cause reduced breathing when the airway collapses during sleep. Lung diseases such as COPD can also cause hypoventilation, as can deformities in the chest wall. The latter can make it difficult to inhale and exhale, leading to inferior ventilation.
Medication and Hypoventilation
As mentioned previously, some doctor-prescribed medications can cause hypoventilation, especially if misused. Central nervous system depressants and certain psychoactive drugs have the potential to cause reduced breathing, as can sedatives. It is vital to take all these medications responsibly and as a doctor instructs. Overdosing can lead to not only to hypoventilation but other serious medical problems and even death.
How Do Doctors Diagnose Hypoventilation?
A doctor may diagnose hypoventilation in several different ways, depending on the symptoms the patient reports. A chest x-ray will look for irregularities that could impede breathing. A lung function test indicates how well the lungs are working to take in and breathe out air. Such a test is often accompanied by a blood gas test that measures the amounts of oxygen and carbon dioxide in the blood. Other tests include pulse oximetry, hemoglobin, and sleep tests, the latter of which would recognize sleep apnea or related conditions.
Luckily, hypoventilation is highly treatable. The treatment always depends on the cause. For instance, if obesity causes breathing difficulty, weight loss can alleviate symptoms. Oxygen therapy can also be helpful to reintroduce more oxygen into the body. CPAP machines can keep the airway unobstructed during sleep. Inhaled medications can treat lung diseases like COPD. Finally, surgery can correct chest deformities causing insufficient breathing.