Respiratory Effort Related Arousal (RERA) is a form of sleep-disordered breathing that can significantly impact sleep quality. It involves an increase in breathing effort during sleep, which leads to brief awakenings, known as arousals. These arousals typically occur without significant drops in oxygen levels in the blood, distinguishing RERA from other, more severe sleep breathing disorders.
Understanding Respiratory Effort Related Arousal
A RERA is defined by a sequence of breaths lasting at least 10 seconds, characterized by increased respiratory effort that culminates in an arousal from sleep. This increased effort occurs as the upper airway narrows, making it harder to breathe. The brain responds to this heightened effort by briefly waking the individual, even if they don’t consciously remember it. RERAs differ from obstructive sleep apnea (OSA) and hypopneas because they do not meet the criteria for significant oxygen desaturation or a substantial reduction in airflow. While OSA involves a 90% or greater reduction in airflow for at least 10 seconds, and hypopneas involve a 30% or greater reduction in airflow for at least 10 seconds accompanied by a 3% or 4% oxygen drop or an arousal, RERAs involve a milder decrease in nasal breathing. The defining feature of a RERA is the increased effort to breathe against airway obstruction, which leads to a cortical arousal, rather than a quantifiable drop in oxygen or airflow.
Common Signs and Symptoms
Individuals experiencing RERAs may notice various symptoms that stem from fragmented sleep. Excessive daytime sleepiness and chronic fatigue are common complaints, as the frequent brief awakenings prevent restorative deep sleep stages. People often report waking up feeling unrefreshed, even after what seems like an adequate duration of sleep. Other indicators can include frequent nocturnal awakenings, morning headaches, and a dry mouth upon waking. A bed partner might observe subtle snoring or restless sleep as the individual struggles to breathe. These disruptions to sleep architecture can also lead to difficulty concentrating during the day.
How RERA is Diagnosed
Diagnosing RERA primarily involves an overnight sleep study, known as polysomnography (PSG). This comprehensive test monitors various physiological parameters during sleep. RERAs are identified by specific criteria, often requiring more detailed monitoring of breathing effort. The gold standard for measuring respiratory effort is esophageal pressure (Pes) monitoring, which involves placing a catheter in the esophagus to detect subtle increases in inspiratory effort that precede an arousal. However, because esophageal manometry can be uncomfortable and disruptive, the American Academy of Sleep Medicine (AASM) also recommends using a nasal pressure cannula. This method identifies RERAs by detecting a flattening of the inspiratory portion of the nasal pressure waveform, indicating airflow limitation, followed by an arousal from sleep.
Treatment Options for RERA
Managing RERA often involves various therapeutic approaches aimed at reducing respiratory effort and improving sleep quality. Positive airway pressure (PAP) therapy is a common and effective treatment. These devices deliver pressurized air through a mask to keep the upper airway open during sleep, preventing the increased breathing effort that leads to arousals. Oral appliance therapy offers another solution. These custom-made devices, such as mandibular advancement devices (MADs) or tongue-retaining devices (TRDs), work by repositioning the jaw or tongue forward to enlarge and stabilize the pharyngeal airway. This mechanical protrusion helps reduce the collapse of the airway and diminishes palate vibration, thereby alleviating breathing obstructions. Lifestyle modifications also serve as supportive measures in RERA management. These can include maintaining a healthy weight, as obesity can contribute to upper airway narrowing. Avoiding alcohol before bed is also beneficial, as it can relax throat muscles and worsen breathing difficulties. Optimizing sleep hygiene, which involves consistent sleep schedules and a comfortable sleep environment, can improve overall sleep quality. Positional therapy, such as sleeping on one’s side, may also help reduce airway collapse in some individuals.
Health Consequences of Untreated RERA
Untreated RERA can lead to significant long-term health consequences due to chronic sleep fragmentation. The persistent disruption of sleep architecture can increase the risk of developing hypertension, a condition characterized by high blood pressure. This elevated blood pressure can, in turn, contribute to other cardiovascular problems over time. Furthermore, chronic sleep fragmentation has been linked to insulin resistance, which can increase the risk of developing type 2 diabetes. Cognitive impairment is another potential outcome, manifesting as difficulties with concentration, memory issues, and reduced overall mental sharpness. Beyond these physical health risks, the ongoing impact of poor sleep can negatively affect an individual’s quality of life, mood, and daily functioning.