Continuous Positive Airway Pressure (CPAP) therapy is the standard treatment for obstructive sleep apnea, effectively keeping the airway open during sleep. While CPAP significantly improves sleep quality and health, some users report experiencing dizziness or vertigo, the sensation of spinning or unsteadiness. This unexpected side effect can be concerning for new and long-term users. Understanding the physiological mechanisms at play is the first step toward finding a solution and continuing effective therapy.
The Direct Link: Pressure Changes and the Inner Ear
The positive pressure generated by a CPAP machine is delivered through the nasal passages and throat. This pressurized air can be transmitted to the middle ear via the Eustachian tube, a narrow canal connecting the middle ear to the back of the nose. Normally, the Eustachian tube opens briefly to equalize the pressure inside the middle ear with the ambient pressure, similar to when yawning or swallowing.
If the Eustachian tube is blocked or sluggish due to inflammation from a cold, allergies, or chronic sinus issues, CPAP pressure can build up behind the eardrum. This pressure imbalance affects the vestibular system, which is housed in the inner ear and controls balance. The resulting stimulation can manifest as dizziness, a feeling of fullness, or a spinning sensation known as alternobaric vertigo.
In some cases, the inability of the Eustachian tube to equalize pressure can lead to otic barotrauma, where the pressure difference causes inflammation or injury to the middle or inner ear structures. This transmission of pressure into the inner ear directly interferes with the body’s equilibrium sensors. Middle ear pressure increases proportionally to the pressure delivered by the CPAP device, highlighting the link between machine setting and ear discomfort.
Systemic Causes Related to Airflow and Settings
Dizziness can also arise from changes in the body’s gas exchange, separate from direct ear pressure issues. When users first begin CPAP therapy or feel anxious while wearing the mask, they may unconsciously breathe faster or deeper than normal, a phenomenon called hyperventilation. This increased ventilation causes the body to expel too much carbon dioxide (CO2).
The resulting state of low carbon dioxide levels, known as hypocapnia, triggers a response in the brain. Low CO2 causes the blood vessels in the brain to constrict, reducing blood flow, which leads to lightheadedness, confusion, or dizziness. If the prescribed pressure setting is too high, it can make exhaling difficult and potentially trigger this pattern of over-breathing.
Experiencing discomfort from a high-pressure setting can induce anxiety, perpetuating the hyperventilation cycle. The CPAP pressure must be effective enough to prevent airway collapse but comfortable enough to allow normal, relaxed breathing throughout the night.
Troubleshooting and Adjustments for User Relief
Addressing dizziness often begins with practical adjustments to the machine and its accessories. Ensuring the CPAP mask has a correct, leak-free seal is necessary, as air leaks can compromise therapeutic pressure or cause air jets to reach the Eustachian tubes. The headgear should be snug enough to prevent leaks but not so tight that it causes discomfort.
Utilizing the “ramp” feature on the CPAP machine can mitigate the feeling of too much pressure at the start of the night. This feature starts air delivery at a low, comfortable pressure and gradually increases it until the full prescribed pressure is reached. For individuals with chronic nasal congestion or allergies, using a heated humidifier and heated tubing adds moisture to the air, which prevents the drying and irritation of the nasal passages and Eustachian tubes.
If dizziness persists despite these adjustments, the pressure setting may need modification. It is important to discuss symptoms of lightheadedness or pressure discomfort with a sleep physician, as pressure changes should only be made under medical guidance. The physician may consider lowering the prescribed pressure or adjusting the machine’s pressure relief settings, which make it easier to exhale against the airflow.
When Dizziness Signals a Different Problem
Dizziness is a symptom that can be caused by many conditions unrelated to CPAP use. Dizziness or vertigo accompanied by other significant symptoms, such as a severe headache, sudden changes in hearing, or new neurological changes, requires immediate medical attention. These signs may indicate an underlying medical issue, and self-troubleshooting should cease immediately.
Untreated sleep apnea itself is a recognized cause of dizziness, often due to repeated drops in blood oxygen levels during the night. The intermittent oxygen deprivation and subsequent blood pressure fluctuations characteristic of sleep apnea can impair blood flow to the brain and the inner ear. Therefore, if dizziness began before starting CPAP, it may be a symptom of undiagnosed or undertreated sleep apnea.
For patients with sleep apnea, the risk of conditions like vestibular migraine and Menière’s disease is elevated, which can independently cause episodes of severe vertigo. If the dizziness continues even when not using the CPAP machine, a medical evaluation is necessary to rule out other causes, such as inner ear disorders or cardiovascular issues. Treating sleep apnea effectively has been shown to reduce or resolve dizziness in many patients.