Sleep Apnea | Are You Unknowingly Pausing Your Breath While You Sleep?

Sleep apnea is a clinical sleep disorder characterized by recurrent interruptions of breathing during sleep. These pauses, known as apneas, can last from a few seconds to over a minute and may occur hundreds of times per night. The two principal forms are Obstructive Sleep Apnea (OSA) and Central Sleep Apnea (CSA). OSA is the most prevalent type, resulting from a physical blockage of the upper airway. During sleep, the muscles in the throat relax excessively, causing soft tissues, such as the tongue and soft palate, to collapse and obstruct airflow despite continued effort to breathe. This leads to loud snoring, gasping, or choking sounds as the individual struggles to resume breathing. In contrast, CSA is a neurological issue where the brain fails to send the proper signals to the muscles that control breathing. The airway is not physically blocked, but the respiratory effort ceases entirely for a brief period. This form is less common and is often associated with underlying medical conditions, such as heart failure or stroke, or the use of certain medications. Both types degrade sleep quality and prevent the brain from receiving a consistent supply of oxygen.

The primary consequence of sleep apnea is intermittent hypoxia, a state of repeated oxygen deprivation. Each apnea event causes a drop in blood oxygen levels, triggering a brief arousal from sleep to reopen the airway. While these awakenings are typically too short to be remembered, they fragment the sleep cycle, preventing the individual from reaching the deeper, restorative stages of sleep. This chronic sleep fragmentation and hypoxia have significant detrimental effects on cognitive function. Individuals often experience excessive daytime sleepiness, difficulty concentrating, memory lapses, and reduced executive function. Neurologically, prolonged oxygen deprivation can damage brain cells and is linked to an increased risk of cognitive decline. Physiologically, the stress placed on the body from frequent awakenings and low oxygen levels elevates blood pressure and increases the risk for serious cardiovascular problems, including hypertension, heart attack, and stroke.

Several factors increase the likelihood of developing sleep apnea. The most significant risk factor for OSA is excess body weight, as fat deposits around the upper airway can obstruct breathing. Anatomical characteristics also play a crucial role; these include a large neck circumference, a narrow throat, or structural features like enlarged tonsils or adenoids. Men are diagnosed with sleep apnea more frequently than women, although the incidence in women increases significantly after menopause. Age is another factor, as muscle tone in the throat tends to decrease over time. Lifestyle choices, such as alcohol consumption and the use of sedatives, can exacerbate the condition by further relaxing the airway muscles.

While loud, chronic snoring is a hallmark symptom, many other signs can indicate the presence of sleep apnea. Waking up with a very sore throat or a dry mouth is common due to breathing through the mouth when the airway is obstructed. Morning headaches are another frequent complaint, resulting from low oxygen levels during the night. Excessive daytime sleepiness (EDS) is a critical indicator, where an individual feels overwhelmingly tired during the day and may fall asleep unintentionally. Other subtle signs include mood changes like irritability or depression, difficulty concentrating (often described as "brain fog"), and nocturia (waking up frequently during the night to urinate).

A definitive diagnosis of sleep apnea requires a formal sleep study. The gold standard for diagnosis is an in-lab polysomnography (PSG). During a PSG, the patient sleeps overnight in a specialized clinic while various physiological functions are monitored, including brain activity (EEG), eye movements, muscle activity, heart rate, respiratory effort, airflow, and blood oxygen levels. An alternative for suspected moderate to severe OSA is a Home Sleep Apnea Test (HSAT), which uses portable monitors to record fewer variables, such as breathing and oxygen levels, in the patient's home. The severity of sleep apnea is quantified using the Apnea-Hypopnea Index (AHI), which measures the average number of apnea (complete cessation of breathing) and hypopnea (partial cessation) events per hour of sleep. An AHI of 5-15 is mild, 15-30 is moderate, and an AHI above 30 is considered severe.