Upper airway resistance syndrome (UARS) is a sleep-related breathing disorder in which the airway narrows enough during sleep to disrupt rest, but not enough to cause the oxygen drops seen in obstructive sleep apnea. The result is repeated micro-awakenings throughout the night that fragment sleep and cause significant daytime symptoms, even though a standard sleep study may look nearly normal. UARS sits on the spectrum between simple snoring and obstructive sleep apnea, and it’s frequently missed.
How UARS Differs From Sleep Apnea
In obstructive sleep apnea (OSA), the airway collapses partially or completely, reducing airflow by 30% or more (hypopnea) or nearly stopping it entirely (apnea). These events last at least 10 seconds and cause blood oxygen levels to drop. UARS doesn’t do that. Instead, the airway narrows just enough to increase resistance to airflow. Your body works harder to pull air through, generating increasingly negative pressure inside the chest, until the effort itself triggers a brief arousal from sleep. These events are called respiratory effort-related arousals, or RERAs.
RERAs involve 10 or more seconds of decreased nasal breathing followed by an arousal, but critically, they don’t cause a measurable drop in blood oxygen. This is the key distinction. Because oxygen levels stay stable, many standard sleep studies that focus on apneas and hypopneas will report a low or normal score, leading clinicians to conclude nothing is wrong. Meanwhile, the person is waking up dozens of times per hour without knowing it.
What Happens in Your Airway During Sleep
Your throat, unlike your windpipe, is a collapsible tube. It stays open through a balance between the muscles that actively hold it open and the suction-like negative pressure created every time you inhale. During sleep, muscle tone naturally decreases. In someone with UARS, this relaxation is enough to narrow the airway and increase resistance to airflow, even though the airway doesn’t fully collapse.
As the airway narrows, each breath requires more effort. The diaphragm pulls harder, creating greater negative pressure inside the chest. This mounting effort eventually triggers the brain to briefly wake you up, just enough to restore muscle tone and reopen the airway. You fall back asleep immediately, the cycle repeats, and you never become conscious of it happening. The result is sleep that looks continuous from the outside but is deeply fragmented at a neurological level.
Who Gets UARS
The typical UARS patient looks quite different from the typical sleep apnea patient. People with UARS tend to be leaner, with a body mass index at or below 25, and younger, with an average age around 37. The condition affects men and women roughly equally, and it may actually represent a larger proportion of sleep-related breathing disorders in women than OSA does. This demographic profile is part of why UARS gets overlooked: clinicians often screen for sleep-disordered breathing in overweight, middle-aged men, and the lean young woman with crushing fatigue doesn’t fit that template.
Facial structure plays a role. A smaller or more recessed lower jaw reduces the space available for the tongue and soft tissues, making the airway more prone to narrowing. Enlarged tongue volume and the positioning of the hyoid bone (the small bone in the neck that supports the tongue) also contribute to airway crowding. In men specifically, a shorter, shallower mandible is an independent risk factor for airway obstruction during sleep. These are subtle anatomical features, not obvious deformities, which is another reason UARS often flies under the radar.
Symptoms Beyond Sleepiness
Daytime sleepiness is the hallmark complaint, but UARS produces a broader constellation of symptoms that can send people to multiple specialists before anyone considers a sleep disorder. Fatigue, difficulty concentrating, and unrefreshing sleep are common. Hypertension is an important consequence, likely driven by the autonomic nervous system responding to repeated swings in chest pressure throughout the night. The cardiovascular stress of UARS is real, even without oxygen desaturation.
UARS was originally described in 1982 in children, where it presented as frequent snoring, restless sleep, and sweating during the night. In kids, the symptoms extended to changes in appetite, poor school performance, and behavioral problems. In adults, the presentation is more likely to center on chronic fatigue, headaches, insomnia-like complaints, and a general sense that sleep isn’t restorative no matter how many hours you get.
How UARS Is Diagnosed
A standard polysomnography (overnight sleep study) can detect RERAs if the scoring technicians are looking for them. The challenge is that many labs focus primarily on counting apneas and hypopneas to calculate an apnea-hypopnea index, or AHI. If your AHI comes back below 5 (the threshold for an OSA diagnosis), you may be told your sleep is normal, even if you’re having 20 or 30 RERAs per hour.
The gold standard for measuring the increased breathing effort that defines UARS is esophageal manometry. This involves placing a thin, fluid-filled catheter through the nose into the esophagus during a sleep study. Because the esophageal wall expands and contracts with the respiratory cycle, the catheter can detect transmitted changes in chest pressure, providing an indirect but highly accurate measurement of how hard the body is working to breathe. The American Academy of Sleep Medicine recognizes esophageal pressure monitoring as the reference standard for measuring respiratory effort.
In practice, esophageal manometry is uncomfortable and not widely available, so most sleep labs rely on nasal pressure transducers and respiratory inductance bands to identify RERAs. These tools are less sensitive but can still catch the pattern of increasing effort followed by arousal that characterizes UARS. If you suspect UARS, it helps to work with a sleep center that routinely scores RERAs and reports the respiratory disturbance index (which includes RERAs) rather than just the AHI.
Treatment Options
Positive airway pressure therapy, typically CPAP, is the most effective treatment for UARS. The pressurized air acts as a pneumatic splint, keeping the airway open and eliminating the resistance that triggers arousals. Because the airway narrowing in UARS is subtler than in OSA, the pressure settings needed are often lower, which can make the device more comfortable to use.
For people who can’t tolerate CPAP, oral appliances offer a solid alternative. These custom-fitted devices are worn during sleep and work by repositioning the lower jaw slightly forward, which increases the space behind the tongue and reduces airway resistance. Stanford Health Care notes that while oral appliances are typically not as effective as CPAP, they are an excellent option for people who struggle with a mask. A follow-up sleep study is usually recommended to confirm the appliance is working.
Surgical options exist for people with identifiable anatomical contributions, such as enlarged tonsils, a deviated septum, or significant jaw deficiency. Myofunctional therapy, which involves exercises to strengthen the tongue and throat muscles, has gained attention as a supplemental approach, but current evidence for its use specifically in UARS is lacking. There is no established protocol or demonstrated efficacy for myofunctional therapy in this condition, though it continues to be studied in the broader context of sleep-disordered breathing.
Why UARS Matters
The consequences of untreated UARS are not trivial. Chronic sleep fragmentation impairs cognitive function, mood regulation, and cardiovascular health. The link to hypertension is particularly concerning because it means UARS carries real long-term health risks, not just quality-of-life complaints. Many people with UARS spend years being evaluated for chronic fatigue syndrome, depression, or insomnia before the underlying breathing disorder is identified.
Whether UARS is a distinct condition or simply an early stage on the continuum toward obstructive sleep apnea remains debated in sleep medicine. Some evidence suggests that untreated UARS can progress to OSA over time as tissues lose tone and weight changes occur. Regardless of where it sits in the classification, the clinical reality is straightforward: if your sleep is being disrupted by increased airway resistance, identifying and treating it can be transformative.