Obstructive breathing in sleep can vary greatly in severity from very mild snoring of minimal consequence to severe stoppages in breathing leading to drops in the blood oxygen level and disruption of sleep. We believe that obstructive breathing in sleep in any given individual generally begins with "benign snoring" that, in its earliest stages, may have minimal disruption to sleep. Over time as the patient ages or gains weight, however, this snoring or upper airway resistance may increase, leading to “snore arousals”. That is, the snoring begins to cause many brief awakenings during sleep without affecting the blood oxygen levels and essentially "robbing" the individual of their "good" sleep.
Snoring is the sound emitted from the upper airway of your throat during sleep and comes from loose, relaxed tissues that vibrate while breathing. The sound emitted may come from the soft palate, tongue or both. Snoring is an indication that there is resistance through the airway. The sound intensity varies from person to person and is commonly described as a nuisance by a bed partner. Snoring may be an indicator of a serious health condition called Obstructive Sleep Apnea (OSA). Approximately one out of every two snorers will develop this condition. Although snoring is an indicator for sleep apnea, it is not necessarily experienced by all patients with this disorder.
Upper Airway Resistance Syndrome
When the snoring and resistance through the airway is significant enough to disrupt the quality of sleep, we call this disorder "Upper Airway Resistance Syndrome" or UARS. In patients with UARS, the sleep quality is generally disrupted to the point of causing clinical consequences such as difficulty initiating or maintaining sleep (insomnia), non-refreshing sleep, or excessive daytime sleepiness. Because of the very brief nature of the many arousals triggered by snoring, patients with UARS are typically unaware of these awakenings and generally do not know that they may be snoring if it were not for the witnessed reports from a bed partner or family member.
It is also important to note that not all patients with UARS have audible snoring. Some patients may have an increase in respiratory effort during inhalation or inspiration because of an anatomical limitation to the airway such as from an enlarged tongue base, which may be heard as “heavy breathing” instead of snoring. The increased effort to inhale can lead to EEG (brain wave) arousals and has been referred to in the sleep medicine field as "respiratory effort-related arousals" (RERAs). For this reason, an absence of snoring does not imply an absence of obstructive breathing in sleep. Such individuals, however, may have other symptoms such as a dry mouth upon awakening, morning headaches, symptoms of insomnia or daytime sleepiness.
We now believe that UARS represents a progression of disease bridging the transition from "benign snoring" to obstructive sleep apnea. 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.
At the Ohio Sleep Medicine Institute, we believe that it is important to identify patients with UARS since they have a particularly higher risk of developing obstructive sleep apnea in the future. These individuals may minimize the progression to sleep apnea through weight reduction, for example. There is also a body of research data to suggest that chronic snoring may actually cause more collapsibility of the upper airway through vibration trauma of the tongue and soft palate against the pharyngeal muscles of the upper airway responsible for keeping the airway open during sleep. More research is needed to determine if we should more aggressively treat “benign snoring” to prevent further progression of the disease to obstructive sleep apnea.
An important reason to treat UARS is to allow the patient to obtain a better quality of sleep (see treatment options for obstructive breathing in sleep). Opening the airway or decreasing the upper airway resistance can reduce the number of awakenings or arousals during sleep, improve the ability to initiate or maintain sleep, lead to more refreshing sleep, and improve daytime alertness.