by Dr. Jon Avery Go
You may think the person sleeping next to you is simply a loud snorer. But what sounds like ordinary snoring may actually be a sign of a condition in which breathing repeatedly stops and starts throughout the night. Obstructive sleep apnea can raise blood pressure, disrupt heart rhythms, and impair daytime alertness.
Obstructive sleep apnea (OSA) is one of the most common sleep-related breathing disorders. It occurs when the upper airway repeatedly collapses during sleep, resulting in obstructive apneas, hypopneas and brief arousals from sleep. The condition is remarkably common. Depending on how it is defined, approximately 15% to 30% of men and 10% to 15% of women in North America have OSA. Worldwide estimates suggest that hundreds of millions of adults between ages 30 and 69 have at least mild sleep apnea.
OSA becomes more common with age and is more common in men, although the difference between men and women becomes much smaller after menopause. Craniofacial anatomy, upper-airway abnormalities, nasal obstruction and family history can also contribute. Some people with OSA are overweight, while others have a normal body weight. That is one reason the condition can go unrecognized.
Common symptoms are loud snoring, witnessed pauses in breathing, and gasping or choking during sleep. This may lead to fatigue, poor concentration, low energy, insomnia, or waking up without feeling refreshed. Morning headaches occur in approximately 10% to 30% of patients with untreated OSA.
OSA is a cardiovascular concern because repeated obstruction during sleep can place considerable physiological stress on the body. Patients with OSA, particularly moderate and severe untreated disease, have increased rates of hypertension, coronary artery disease, cardiac arrhythmias, heart failure and stroke.
The association with high blood pressure is particularly important. OSA is common among people with hypertension, especially those whose blood pressure remains difficult to control.
The relationship between OSA and atrial fibrillation, or AFib, is also noteworthy. Studies have found substantially higher rates of AFib among patients with sleep apnea, and OSA appears to be associated with an increased risk of recurrent AFib following treatment such as catheter ablation. This has practical implications. A patient who develops AFib, particularly when other symptoms of sleep apnea are present, may warrant evaluation for an underlying sleep disorder.
Repeated sleep disruption due to OSA can interfere with attention, memory and executive function. Patients may describe themselves as tired rather than sleepy, making the problem easy to overlook. Patients may fall asleep while watching television, reading or sitting quietly can be an important warning sign.
More concerning is falling asleep while driving. Motor vehicle crashes are reported to be two to three times more common in patients with OSA than in those without it. For people whose occupations involve driving, operating machinery, or other safety-critical responsibilities, recognizing excessive sleepiness is particularly important.
OSA also intersects with metabolic health, particularly diabetes. People with OSA have higher rates of insulin resistance and type 2 diabetes. Although obesity is a major shared risk factor, studies have reported associations between OSA severity and metabolic abnormalities even after accounting for obesity.
In patients with metabolic syndrome, OSA has also been associated with abnormalities involving glucose, triglycerides, inflammation, arterial stiffness, and atherosclerosis. This suggests that sleep apnea may be part of a broader cardiometabolic problem rather than an isolated nighttime disorder.
A questionnaire can help identify people who are at increased risk, but it is important to understand that sleep apnea cannot be diagnosed by symptoms or a questionnaire alone. Objective sleep testing is required. An overnight laboratory polysomnogram remains the gold-standard diagnostic test.
However, for appropriately selected patients with a high likelihood of uncomplicated moderate-to-severe OSA, a home sleep apnea test can be an appropriate alternative. Home testing is convenient and may shorten the time between diagnosis and treatment. But it isn’t appropriate for everyone.
Patients with certain significant medical conditions, suspected complex sleep disorders, or persistent symptoms after a negative or inconclusive home test may require an in-laboratory study. When clinical suspicion remains high despite a negative home study, further evaluation should be considered.
The apnea-hypopnea index, or AHI, is found in the sleep study and is commonly used to describe the frequency of breathing events during sleep. Traditionally, 5–14 events per hour is mild OSA, 15–30 events per hour is moderate OSA, and more than 30 events per hour is severe OSA. Severity, however, should not be judged by the AHI alone.
Symptoms and other medical conditions are also important. Severe OSA is associated with increased cardiovascular comorbidity, including hypertension, coronary artery disease and arrhythmias.
Continuous positive airway pressure, commonly known as CPAP, is one of the principal treatments for OSA. It keeps the upper airway open during sleep and can dramatically reduce obstructive breathing events. CPAP can also improve daytime symptoms and lower blood pressure. But there is an important distinction between treating sleep apnea effectively and proving that treatment prevents cardiovascular events.
Randomized clinical trials have not consistently demonstrated that PAP therapy reduces major cardiovascular events or cardiovascular mortality in every patient with OSA. A 2023 analysis of more than 4,000 participants, however, found a lower rate of cardiovascular and cerebrovascular events among patients who demonstrated good adherence to PAP therapy—defined as at least four hours per night—although researchers noted that the finding could partly reflect differences between patients who adhere well to treatment and those who do not.
In practical terms, CPAP remains an important treatment, but it should be considered part of comprehensive health care rather than a replacement for controlling other cardiovascular risk factors.
It is recommended to talk to your doctor about sleep apnea if you or your partner notice loud, habitual snoring, pauses in breathing during sleep, gasping or choking at night, excessive daytime sleepiness, and more.
Other common symptoms include morning headaches, poor concentration or unexplained fatigue, repeated nighttime awakenings, high blood pressure that is difficult to control, and atrial fibrillation or other nighttime palpitations. The presence of these symptoms does not prove that someone has OSA. But they are reasons to discuss whether a sleep evaluation is appropriate.
One of the challenges with obstructive sleep apnea is that people often get used to the warning signs. Loud snoring can be brushed off as nothing more than an annoyance. Feeling tired during the day may be blamed on a busy schedule, stress or simply getting older. Even falling asleep while watching TV might not seem like a cause for concern. But repeatedly stopping and starting breathing during sleep is not normal.
People with OSA can have hundreds of episodes of narrowed or blocked airways during the night. These interruptions can prevent the body from getting the deep, restful sleep it needs and can lead to problems with daytime alertness and concentration. Over time, untreated OSA is also linked to conditions such as high blood pressure, heart disease and diabetes.
DR. JON AVERY GO is a board-certified Internal Medicine physician. He practices as a primary care doctor at Primary Care Clinic of Hawaii.
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