Sleep Fundamentals || UARS is for Upper Airway Resistance Syndrome

From our Sleeping is Fundamental series

Sleep apnea is not the only sleep breathing disorder. UARS could be even more common.


UARS sleep fundamentalsWhat is Upper Airway Resistance Syndrome?

Upper airway resistance syndrome (UARS) is defined as a sleep-breathing disorder which does not qualify as full-blown sleep apnea. The difference between UARS and obstructive sleep apnea (OSA) is one of degrees, in a sense: UARS only yields a partial blockage of the airway as one sleeps.

UARS and snoring

UARS is not a fancy name for snoring, but it includes snoring as one of its symptoms. It can also refer to so-called “silent snoring,” in which obstructions in breathing occur during sleep which are not detected by a sleeping partner.

Silent snoring is a problem because, with upper airway resistance, the airway narrows so much that the muscles of breathing along the ribcage and the diaphragm work double duty to inhale. This increased effort to breathe while sleeping can lead to systemic health problems in the long term.

The Ohio Sleep Medicine Institute refers to these as “snore arousals.” In technical terms, these are called RERAs (Respiratory Event Related Arousals); they differentiate from apneas primarily in that they do not result in the reduction in blood oxygen that makes OSA so dangerous.

However, silent snoring isn’t an innocuous problem. People with UARS experience frequent RERAs all night long which interfere with their ability to sleep deeply; they suffer the dreaded “fragmented sleep” that is the same demon behind insomnia, sleep apnea, and other sleep disorders.

Fragmented sleep is dangerous; it leads to health and relationship problems and can be the cause behind traffic and work accidents.

Diagnosing and treating UARS

Unfortunately, people with UARS can remain undiagnosed and/or untreated because, well, if it’s not sleep apnea, then use of a Positive Airway Pressure (PAP) device or other treatment to alleviate UARS may never occur.

Why not? Traditionally, insurance companies have been unwilling to acknowledge UARS as a legitimate sleep breathing disorder. This, despite its prevalence, weighing in at about 1 in 7 sleepers. The Ohio Sleep Medicine Institute refers to UARS as “the orphan child of sleep medicine” for this reason.

While the discovery of UARS as a certifiable sleep breathing issue took place in 1993 at Stanford, diagnosing and treating it have been inconsistent at best.

The initial identification of the syndrome came as a result of sleep lab patients having disruptions in their breathing that didn’t quite fall into the apnea category. They were still tired, still suffering physically and mentally even if they didn’t “qualify” for PAP therapy. But they don’t always get therapy for this problem.

When UARS remains untreated

Untreated UARS can evolve from its “harmless” position in the hierarchy of sleep breathing disorders—between snoring and apneainto full-blown OSA. We’ve already talked about what untreated OSA can do to the human body. (It’s not pretty.)

UARS is also often misdiagnosed as Chronic Fatigue Syndrome (CFS), fibromyalgia, depression, mood disorder, attention deficit hyperactivity disorder (ADHD), or migraine by primary care physicians who do not think to have their patients undergo a sleep study, where the imprint of UARS on respiratory recordings as RERAs is hardly a mystery.

Whether a lab tech or a doctor counts RERAs or not in their diagnostic tests actually makes a difference in the final diagnosis; yet, even then, insurance companies may still not be satisfied and refuse to reimburse for treatments.

So… it would make sense to identify and treat UARS in order to prevent full-blown OSA (and all of these other problems), wouldn’t it? As a form of preventive medicine?

The Ohio Sleep Medicine Institute explains the importance of diagnosing and treating UARS here:

“Patients simply do not go to bed normal one night, only to awaken the next morning with obstructive sleep apnea. Instead, they typically go through natural progression over time or following weight gain from ‘benign snoring,’ to UARS, and finally to obstructive sleep apnea. This progression may take years or decades to occur.”

Other impacts from untreated UARS

    • Acid reflux, heartburn, gastroesophageal reflux disease (GERD), laryngopharyngeal reflux disease (LPRD)
    • Bruxism (teeth grinding and jaw clenching)
    • Chronic insomnia
    • Excessive daytime somnolence
    • Headaches
    • Hypertension
    • Hypotension
    • Irritable bowel syndrome (IBS)
    • Memory problems
    • Morning nasal congestion
    • Night sweats
    • Nocturia
    • Non-refreshing sleep (or, waking up tired)
    • Parasomnias like confusional arousal, sleepwalking, sleeptalking, sleep paralysis

Dr. Steven Park is a popular activist on the subject of sleep-disordered breathing; his excellent podcast here gives very clear descriptions of what can happen if you let UARS go untreated.

What causes UARS?

Like OSA, the causes of UARS are primarily mechanical in nature.

  • The tongue is overlarge.
  • The upper airway passages (nasal, pharyngeal) are congenitally narrow.
  • The adenoids or the uvula get in the way.
  • People with UARS often have a high narrow palate or an overbite.
  • Other problems, like allergies, and chronic respiratory infections like rhinitis, swell the mucous membranes lining the airways, thereby narrowing them.
  • A deviated septum might be the obvious source of UARS-related obstruction.
  • Swollen turbinates or collapsing nasal valves can also lead to UARS.
  • Edema anywhere in the body (even in that far-off location, the ankles) can be redistributed at night while the body is horizontal, sending more fluid up into the neck, creating weight and swelling there that can close off the space you need to breathe. (Pregnant women suffer a lot from UARS, perhaps without even knowing it.)

What distinguishes UARS from full-blown OSA?

      • OSA prevails in men, but women are more likely to suffer from UARS
      • OSA is more common in older people, while UARS occurs in patient of all ages, even the very young
      • OSA often accompanies someone with obesity, whereas UARS sufferers often have normal BMI or are even underweight
      • People with UARS suffer more from frequent awakenings and difficulty resuming sleep than those with OSA
      • People with UARS do not always snore, whereas snoring or gasping is a common marker of OSA
      • People with UARS do not have dangerous changes in their airflow during the night; those with OSA have remarkable shifts in which no breathing happens at all
      • People with UARS do not have significant drops in their oxygen saturation; in OSA, patterns of low blood oxygen confirm apnea

UARS is hardly “OSA Lite.” As the website for the Center for Sound Sleep describes it, “To understand the difficulty that someone with UARS has with breathing, try to imagine breathing for an extended period of time through an opening no larger than a small soda straw.”

How to breathe like a boss while you sleep

Treatments for UARS mirror those for OSA.

  • Continuous Positive Airway Pressure (CPAP) therapy combined with cognitive behavior therapy for any underlying secondary behavioral issues is advocated by some; others promote surgical reshaping of the upper airway by removing excess tissue as a solution.
  • Orthodontics can help pediatric patients breathe more easily and correct cranial issues to support healthy breathing in their future while their bodies are still growing.
  • Oral devices, which force the lower jaw forward to open the airway enough to improve airflow, are popular and finally finding some support via reimbursement by insurance companies.
  • Positional therapy for mild cases can work.
  • Weight loss is always a good option as it shrinks the fat pads which store fluids in the neck, therefore freeing up pace for better breathing while asleep.

Still, given all this information we have on hand regarding the legitimate condition of UARS, there are still challenges being made to the ways in which it is assessed and treated.

Some doctors demand that all RERAs (see definition above) be counted during a study, while others don’t consider them until treatment happens.

This ongoing debate about how to measure upper airway resistance (and here’s another link) continues at the peril of thousands of untreated sufferers of UARS.

Let’s hope they can arrive at a consensus soon, and that insurance companies can find wisdom in reimbursing necessary preventive medicine.



Breathing Related Arousals: Call Them What You Want, but Please Count Them.” Collop, N. Journal of Clinical Sleep Medicine. 2014 Feb 15; 10(2): 125–126.

“Frequency and Accuracy of ‘RERA’ and ‘RDI’ Terms in the Journal of Clinical Sleep Medicine from 2006 through 2012.” Krakow B, Krakow J, Ulibarri VA, McIver ND. Journal of Clinical Sleep Medicine. 2014 Feb 15; 10(2): 121–124.

Center for Sound Sleep || Learn More about Upper Airway Resistance Syndrome (commercial site)

Practice Parameters for the Indications for Polysomnography and Related Procedures: An Update for 2005.” Kushida CA, Littner MR, Hirshkowitz M, et al. American Academy of Sleep Medicine, accessed on the web April 15, 2015. (PDF)

Scoring Respiratory Events in Sleep Medicine: Who Is the Driver—Biology or Medical Insurance?” Thomas RJ, Guilleminault C, Ayappa I, Rapoport DM. Journal of Clinical Sleep Medicine, Nov 15, 2014:10(11), 1245–1247. Accessed on the web July 27, 2018.

Cleveland Clinic || Sleep Disordered Breathing

Stanford Center for Sleep Sciences and Medicine || Stealthy Insomnia Cause? Upper Airway Resistance Syndrome Subtly Disturbs Breathing in Sleep (blog)

Dr. Steven Park || Upper Airway Resistance Syndrome (podcast transcription)

Ohio Sleep Medicine Institute || Upper Airway Resistance Syndrome (commercial site)

Upper Airway Resistance Syndrome-One Decade Later.” Bao B, Guilleminault C. Current Opinion in Pulmonary Medicine. 2004;10(6).

Upper airway resistance syndrome: still not recognized and not treated.” Palombini L, Lopes MC, Tufik S, Guilleminault C, Bittencourt LRA. Sleep Science. 2011;4(2):72-78.

SleepyHeadCENTRAL || What happens if I don’t treat my sleep apnea?


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