What Is Upper Airway Resistance Syndrome and How Is it Diagnosed?
When your airways narrow overnight it can cause an obstruction when breathing – known as obstructive sleep apnea (OSA). Another sleep-disordered breathing issue which can intensify if left untreated is upper airway resistance syndrome.
What is Upper Airway Resistance Syndrome?
Upper airway resistance syndrome (UARS) occurs when the soft tissues in the throat relax as we sleep. The relaxed tissues fall back into the throat, narrowing the airways. This leads to increased obstruction within the airways and disturbs air flow as you breathe. The tongue falling back into the throat may have the same effect.
UARS might begin as mild snoring, which can become louder as airways become more obstructed. However, in some cases, there is no snoring at all. For some people with UARS, their breathing will become labored instead from the effort required to breathe.
Although not as severe as obstructive sleep apnea, UARS still results in disrupted sleep. The brain will react to the extra effort required to breathe by briefly arousing the body. Although not serious enough to be classed as sleep apnea, it will still leave you feeling fatigued during the day.
Symptoms of Upper Airway Resistance Syndrome
There are quite a few similarities between UARS and OSA. The two conditions sit along the same spectrum of sleep-disturbance disorders, but UARS is less severe. The symptoms of UARS are along the same lines as those experienced with sleep apnea. These include:
- snoring
- labored breathing
- daytime fatigue
- frequent arousals from sleep
- poor concentration
- memory issues
People with UARS will experience these symptoms in a less severe manner than someone with sleep apnea. However, left untreated, UARS can develop into obstructive sleep apnea, a disorder which increases the risk from serious health issues such as heart disease, stroke and diabetes.
What Are the Differences Between UARS and OSA
For all their similarities, there are some notable differences between UARS and OSA. One of the prime differences is that where both conditions can disturb sleep, UARS does not usually result in pauses to your breathing. In the cases where it does, this will tend to be mild compared to OSA.
Another difference can be seen in those most at risk from both conditions. Whereas a primary contributing risk factor for OSA is obesity, being overweight is not a major factor with UARS. People with UARS are generally of average weight.
OSA is also usually seen more in middle-aged men. Again, this does not tend to apply to UARS. You can be susceptible to developing UARS regardless of sex, age or ethnicity.
Diagnosis of Upper Airway Resistance Syndrome
Once you start displaying the signs of a sleep-disordered breathing problem, diagnosis is key. Left untreated, minor snoring can become UARS, which in turn can then develop into the more severe sleep disorder OSA. Therefore, once you recognize any symptoms you should consult with your doctor.
If your doctor suspects a sleep disorder such as UARS, they will recommend a sleep study. A home sleep test that quantifies the number of Respiratory Effort Related Arousals (RERAs) is helpful.
Alternatively, a polysomnogram at a sleep clinic is a comprehensive test which measures brain waves, breathing patterns, heart rate, blood oxygen levels and any movement you may make while you sleep.
Some sleep labs may ask patients if they are fine to insert an esophageal balloon in the airway to measure the amount of resistance that occurs while breathing.
Patients with UARS will often have a normal Apnea Hypopnea Index <5 events per hour of sleep but an abnormal Respiratory Disturbance Index >5 events per hour of sleep.
Patients with UARS often don’t desaturate either because the subconscious arousals act as an early warning system to prevent the patient from entering deeper stages of sleep. These patients often are severely fatigued as they are unable to reach the deeper stages of REM sleep that are restorative.
The results of the study will show whether you have a sleep disorder -- and the severity of the disorder.
Treating Upper Airway Resistance Syndrome
While UARS is less severe than OSA, treatment methods are very similar. A primary method of treating OSA is CPAP therapy. This involves a device which delivers pressurized air through a mask while you sleep. The air prevents the collapse of the airways, removing the obstruction to your airflow.
However, those with the less severe UARS may not be as tolerant of CPAP, and usually this treatment method is used as a way to overcome the debilitating sense of fatigue these patients experience. . An option is to use an oral appliance which is worn while you sleep.
This appliance is similar to a mouthguard and works by moving the lower jaw forward to help keep the airways clear.
Preventative Measures
Leading a healthier lifestyle can help prevent sleep-disordered breathing issues. Taking more exercise, eating a more nutritious diet and focusing on good sleeping habits can help prevent UARS.
Even if you already display the symptoms of UARS your doctor will likely recommend such lifestyle changes to try and reduce the symptoms. They will also recommend avoiding alcohol and sedative medicines, which relax your throat muscles.
Another preventative measure which can work for both UARS and OSA is positional therapy. When you sleep on your back gravity can pull the loose tissues in the throat down and cause an obstruction in the airways. Sleeping on your side counters this and may help alleviate the symptoms.
Final thoughts
Upper airway resistance syndrome requires treatment otherwise it can eventually develop into the more severe obstructive sleep apnea. It may be your partner who first notices your snoring or any form of breathing issues while you sleep. You may find you are experiencing daytime fatigue or sleepiness too.
As soon as you become aware of any overnight sleeping or breathing issues, book an appointment with your doctor. By diagnosing UARS early you may be able to reverse it through treatment -- and prevent the condition developing into the more severe disorder, obstructive sleep apnea.
Sources:
https://www.webmd.com/sleep-disorders/upper-airway-resistance-syndrome-uars
https://stanfordhealthcare.org/medical-conditions/sleep/upper-airway-resistance-syndrome.html
