The main difference between central sleep apnea and obstructive sleep apnea is what interrupts normal breathing. In obstructive sleep apnea (OSA), the airway is blocked despite continued breathing effort (respiratory effort). In central sleep apnea (CSA), the brain does not consistently signal the muscles that control breathing.
Obstructive sleep apnea occurs when throat muscles relax and tissues around the soft palate, tongue base or epiglottis narrow or block the upper airway during sleep. This can cause loud snoring or gasping. OSA is a common sleep disorder and is more frequent than central sleep apnea.
Central sleep apnea occurs when signals from the central nervous system that regulate breathing are disrupted. During a central apnea, airflow and breathing effort stop, rather than airflow stopping because the throat is blocked.
Sleep apnea symptoms alone cannot reliably distinguish these sleep disorders. Both are forms of sleep-disordered breathing. A sleep study measures breathing patterns to identify the type and guide treatment.
| Feature | Obstructive sleep apnea (OSA) | Central sleep apnea (CSA) |
| Main problem | The upper airway narrows or collapses. | Breathing signals are disrupted. |
| Effort during an apnea | The breathing muscles keep trying to draw air in. | Breathing effort is absent during the pause. |
| Possible symptoms | Snoring, gasping, broken sleep and daytime sleepiness. | Breathing pauses, waking short of breath and daytime sleepiness. Snoring is possible. |
| Sleep testing | Home testing for selected adults, or in-lab polysomnography. | In-lab polysomnography is generally preferred. |
| Treatment focus | Keep the airway open with CPAP, an oral appliance or selected surgery. | Address the cause and provide suitable breathing support. |
Causes and Risk Factors
The causes and risk factors for sleep apnea depend on the type of sleep disorder.
Obstructive sleep apnea is commonly linked to excess body weight, large neck circumference and anatomical risk factors that contribute to upper airway obstruction. It can also occur in people who are not overweight. High blood pressure and Type 2 diabetes often coexist with OSA.
Central sleep apnea is often associated with congestive heart failure, stroke, opioid medicines or high altitude. Sometimes people develop central sleep apnea without an identifiable cause. Older age and male sex are risk factors for both types, but family history, smoking and alcohol use are more commonly discussed in relation to OSA.
For OSA, taking steps to lose weight if you are overweight and avoiding alcohol before bed may help. Sleeping on your side can reduce obstruction when breathing is worse on your back. These measures do not address the underlying causes of central sleep apnea.
What Are the Symptoms?
Symptoms of both types include breathing interruptions, broken sleep, morning headaches, and excessive daytime sleepiness. People with obstructive sleep apnea often snore loudly, choke or gasp at night and wake with a dry mouth. Partners may witness pauses that end with a snort.
Central sleep apnea symptoms may include awakenings with breathlessness or difficulty staying asleep. Snoring can occur with CSA too, so the presence or absence of noise does not establish the diagnosis. Other effects overlap and include daytime fatigue, reduced focus, irritability and low mood.
When to See an ENT Specialist
See an ENT specialist if you snore, stop breathing during sleep, or have nasal congestion or a crowded throat.
You should also seek an evaluation if you have high blood pressure that is hard to control, atrial fibrillation, Type 2 diabetes or sleepiness that affects driving and work. Do not drive when sleepy. Dr Barrie Tan can assess your upper airway and coordinate appropriate sleep testing. Suspected central sleep apnea may also need assessment by a sleep medicine physician and, depending on its cause, a cardiologist or neurologist.
