By Gemifys
You do everything “right” for sleep, and you still wake up exhausted. A sleep study comes back without a clear obstructive sleep apnea (OSA) diagnosis. So what’s going on? For some people, the answer is a lesser-known condition called Upper Airway Resistance Syndrome, or UARS — sometimes described as sleep apnea’s quieter cousin.
UARS vs. Obstructive Sleep Apnea: What’s the Difference?
In obstructive sleep apnea, the airway repeatedly collapses or becomes fully blocked during sleep, causing breathing to stop for measurable periods. UARS involves a narrower airway that doesn’t fully collapse, but the increased effort needed to breathe through it can still repeatedly disrupt sleep. Because the airway isn’t fully obstructing, standard measurements like the Apnea-Hypopnea Index (AHI) — the main metric used to diagnose OSA — can come back normal or only mildly elevated, even though the person is experiencing real, disruptive symptoms.
UARS was first described by researchers at Stanford University’s sleep medicine program in the 1990s, and it’s still not universally recognized as a distinct diagnosis in every clinical setting, which is part of why it’s frequently missed or dismissed.
Common Symptoms People Report
Because the airway narrowing in UARS causes repeated brief arousals rather than full breathing stoppages, the symptom pattern can look different from “classic” sleep apnea. According to general sleep medicine resources like the Sleep Foundation, people with UARS more often report:
- Persistent daytime fatigue and unrefreshing sleep despite adequate hours in bed
- Frequent waking or a sense of “light” sleep, without loud snoring or witnessed pauses in breathing
- Cold hands and feet, low blood pressure, or digestive symptoms in some cases
- Anxiety or a racing heart on waking
These symptoms overlap with many other conditions, which is another reason UARS can take a long time to identify.
Why It’s Often Missed
Standard in-lab or home sleep studies are typically optimized to detect the airflow stoppages and oxygen drops characteristic of OSA. UARS, by contrast, is associated with more subtle patterns, brief arousals tied to increased breathing effort, sometimes called respiratory effort-related arousals (RERAs). Some sleep labs measure and report RERAs routinely; others don’t, which means a study read only for AHI can come back looking “normal” even when a person is experiencing real, repeated sleep disruption.
What Evaluation and Management May Involve
If UARS is suspected, a sleep medicine specialist may look more closely at effort-related arousals and airway anatomy rather than relying on AHI alone. Management approaches discussed in the sleep medicine literature can include some of the same tools used for OSA, such as positive airway pressure therapy or oral appliances, as well as approaches more specific to airway anatomy, like evaluation by an ENT for structural narrowing, or in some cases orthodontic or myofunctional approaches. Which approach, if any, may help depends entirely on individual anatomy and findings, and this is not something to self-diagnose or self-treat from symptoms alone.
The Takeaway
If you have persistent, unexplained fatigue and a sleep study that came back “normal” or only mildly abnormal, it may be worth asking your sleep specialist specifically about UARS and whether your study looked at respiratory effort-related arousals, not just the AHI. A condition that doesn’t fit the classic OSA picture doesn’t mean nothing is going on.
This article is for general educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. If you are experiencing persistent sleep problems or daytime fatigue, please consult a licensed sleep medicine specialist or healthcare provider.
