Sleep Apnea

Obstructive Sleep Apnea (OSA) is a common yet serious sleep disorder characterized by repeated interruptions in breathing during sleep. These interruptions, known as apnea, are caused by the collapse or blockage of the upper airway, leading to significantly reduced or completely halted airflow, despite the body’s efforts to breathe.

What Happens During an Apnea Event?

During an apnea event, breathing temporarily stops, causing oxygen levels in the blood to drop—a condition known as intermittent hypoxemia. In response, the brain detects the oxygen deficiency and initiates a series of physiological responses. One of the primary responses is a brief arousal from sleep—often so short that the person is unaware of it—which allows the airway to reopen and normal breathing to resume.

At the same time, the autonomic nervous system activates, signaling blood vessels to constrict. This vasoconstriction helps redirect limited oxygen to vital organs, particularly the heart and brain. However, this response also causes a rise in blood pressure, which, when occurring repeatedly throughout the night, can have long-term health consequences.

The Effect of OSA on Nocturnal and Daytime Blood Pressure

In individuals without sleep apnea, blood pressure typically decreases by 10–20% during sleep—a phenomenon known as "nocturnal dipping." This natural drop is important for cardiovascular health and gives the heart a chance to rest.

However, in individuals with OSA, this pattern is often reversed. Due to frequent apneic events and the body’s compensatory mechanisms, blood pressure may increase by 10–20% during sleep instead. This condition, known as nocturnal hypertension, not only prevents the cardiovascular system from recovering overnight but also contributes to sustained elevated blood pressure during waking hours.

Over time, the repeated surges in blood pressure during sleep can lead to chronic hypertension, even during the day. This is because the nervous system remains in a heightened state of alertness, maintaining higher blood pressure levels even when the immediate threat (lack of oxygen) is gone.

Long-Term Cardiovascular Risks

Hypertension is a well-established risk factor for several serious health conditions, including:

• Coronary artery disease

• Congestive heart failure

• Stroke

• Myocardial infarction (heart attack)

• Chronic kidney disease

OSA is now recognized as a major contributor to the development and progression of high blood pressure, especially when left untreated.

According to research from the National Sleep Foundation, men with severe OSA were found to be 58% more likely to develop new-onset congestive heart failure compared to those without OSA. Additionally, men aged 40 to 70 with an apnea-hypopnea index (AHI) of 30 or higher—indicating severe OSA—had a 68% increased risk of developing coronary heart disease relative to those with lower AHI scores.

What Are the Sleep Apnea Symptoms?

Common Symptoms of OSA Include:

• Loud, chronic snoring

• Gasping or choking during sleep

• Excessive daytime sleepiness

• Morning headaches

• Difficulty concentrating

• Irritability or mood changes

How to Diagnose and Treat Sleep Apnea?

OSA is typically diagnosed through a sleep study (polysomnography), which monitors breathing patterns, oxygen levels, and other physiological markers during sleep.

Treatment options may include:

• Continuous Positive Airway Pressure (CPAP) therapy

• Lifestyle changes (weight loss, avoiding alcohol, altering sleep position)

• Oral appliances

• Surgical interventions in more severe or resistant cases