ConditionLungs & breathing
Upper Airway Resistance Syndrome (UARS)
Upper airway resistance syndrome (UARS) is a sleep-related breathing disorder in which the airway narrows during sleep, so breathing takes more effort and the brain briefly wakes many times a night. Unlike obstructive sleep apnea, breathing does not fully stop and oxygen levels usually stay normal, so standard home tests can miss it. It causes unrefreshing sleep, daytime fatigue, insomnia, headaches and brain fog, often in younger, slimmer adults. CPAP, oral appliances and treating nasal blockage help.
Also called: UARS, upper airway resistance, respiratory effort-related arousals (RERAs), part of the sleep-disordered breathing spectrum
At a glance
- What it is
- Increased breathing effort during sleep causing frequent brief arousals, without full apneas.
- Who
- Often younger adults, women, and people with a normal BMI; narrow jaws or nasal blockage.
- Symptoms
- Unrefreshing sleep, daytime fatigue, insomnia, headaches, brain fog, snoring (sometimes absent).
- Diagnosis
- In-lab polysomnography measuring respiratory effort-related arousals (RERAs).
- Treatment
- CPAP, oral appliances, nasal treatment, positional therapy, sometimes surgery.
When to get help
Call 911 or go to the ER
- Falling asleep while driving, or near-miss crashes from sleepiness: stop driving and seek urgent assessment; call 911 or your local emergency number if there has been an injury
See a doctor within a day or two
- Witnessed pauses in breathing, choking or gasping during sleep
- Severe daytime sleepiness that interferes with work or safety
Book a routine appointment
- Feeling unrefreshed despite 7 to 9 hours in bed for weeks
- Frequent awakenings, insomnia, morning headaches or poor concentration
- Loud snoring or mouth breathing during sleep
- A home sleep test that was normal but symptoms persist
What happens in UARS
During sleep, the muscles of the throat relax. In people with a narrow upper airway, airflow becomes limited and the breathing muscles must work harder. The brain senses this effort and briefly wakes (an arousal), often too short to remember. These respiratory effort-related arousals (RERAs) can happen dozens of times an hour, fragmenting deep and REM sleep.
UARS sits on a spectrum:
| Simple snoring | UARS | Obstructive sleep apnea | |
|---|---|---|---|
| Airway | Vibrating, partially narrowed | Narrowed with effort | Partially or fully blocked |
| Breathing pauses | No | No full pauses | Yes, apneas and hypopneas |
| Oxygen drops | No | Usually minimal | Often significant |
| Arousals | Few | Many | Many |
| Symptoms | Bed partner disturbed | Fatigue, insomnia | Sleepiness, heart risks |
Many sleep specialists now classify UARS within obstructive sleep apnea, using the respiratory disturbance index (RDI), which counts RERAs. Some consider it a distinct condition.
Symptoms
- unrefreshing sleep and daytime fatigue
- difficulty falling or staying asleep (insomnia)
- frequent awakenings
- morning headaches
- brain fog, poor concentration and memory
- irritability, anxiety or low mood
- snoring, though some people do not snore
- cold hands and feet and low blood pressure in some reports
- digestive symptoms such as reflux or IBS-like symptoms in some people
Symptoms can be mistaken for chronic fatigue syndrome, depression or primary insomnia.
Causes and risk factors
- narrow upper airway: small or recessed jaw, high-arched palate, large tonsils
- nasal obstruction: deviated septum, enlarged turbinates, allergic rhinitis
- mouth breathing
- female sex and younger age
- family history
Unlike sleep apnea, obesity is not a major factor.
Diagnosis
- in-lab polysomnography (sleep study): measures brain waves, breathing effort, airflow and oxygen overnight; nasal pressure sensors or esophageal pressure monitoring detect RERAs
- home sleep apnea tests often miss UARS because they do not measure brain arousals
- examination of the nose, mouth, jaw and throat
- questionnaires for sleepiness and insomnia
- evaluation for other causes of fatigue (thyroid, anemia, depression)
Treatment
Positive airway pressure
CPAP or APAP keeps the airway open with gentle air pressure. Many people with UARS feel much better, though some find it hard to tolerate at first; mask fitting and pressure adjustments help.
Oral appliances
Mandibular advancement devices, custom-made by a dentist, move the lower jaw forward to open the airway. They are a good option for many people with UARS.
Nasal treatment
- saline rinses and steroid nasal sprays for allergies or congestion
- nasal dilator strips
- surgery for a deviated septum or enlarged turbinates
Other options
- positional therapy if symptoms are worse lying on the back
- myofunctional therapy (exercises for the tongue and throat muscles)
- surgery in selected cases: tonsillectomy, or jaw advancement surgery for significant jaw narrowing
- treating insomnia with CBT-I alongside breathing treatment
Outlook
UARS is not usually dangerous in the short term, but it can significantly affect quality of life, mood and performance. Some people progress to obstructive sleep apnea over time, especially with weight gain or aging. With treatment, energy, sleep quality and concentration often improve markedly.
Frequently asked questions
What is upper airway resistance syndrome?
UARS is a sleep breathing disorder where the airway narrows during sleep, making breathing harder and causing many brief awakenings. Breathing does not stop completely, and oxygen levels usually stay normal, but sleep is fragmented and unrefreshing.
What is the difference between UARS and sleep apnea?
In obstructive sleep apnea, breathing repeatedly stops or becomes very shallow, often with oxygen drops. In UARS, breathing becomes effortful and triggers arousals without full pauses or major oxygen drops. Many experts consider UARS a mild part of the sleep apnea spectrum.
What are the symptoms of UARS?
Common symptoms are unrefreshing sleep, daytime fatigue, insomnia, frequent awakenings, morning headaches, brain fog and irritability. Snoring may or may not be present. It often affects younger, slimmer adults.
How is UARS diagnosed?
UARS needs an in-lab sleep study that measures breathing effort and brain arousals. Home sleep tests often miss it because they do not record brain activity or detect subtle airflow limitation.
How is UARS treated?
Treatment options include CPAP, custom oral appliances that move the jaw forward, treating nasal blockage with sprays or surgery, positional therapy and, in selected cases, airway or jaw surgery. Many people feel much more rested with treatment.
Sources
This guide was written from current patient and clinical guidance, including:
- American Academy of Sleep Medicine: International Classification of Sleep Disorders
- American Academy of Sleep Medicine: Clinical Practice Guideline for Diagnostic Testing for Adult Obstructive Sleep Apnea
- Sleep Foundation: Upper Airway Resistance Syndrome
- MedlinePlus: Sleep apnea
- Stanford Health Care: Sleep-Disordered Breathing