Snoring, heart disease and sudden death
(First of two parts)
We saw two patients recently in our clinic, both with problematic cardiovascular ailments. The first one was a 48-year-old overweight mechanic whose blood pressure remained high despite four antihypertensive medicines he was taking at supposedly optimal doses. His family physician was already at his wit’s end and ran out of options to control his blood pressure.
The second patient, whom we haven’t seen for several years, came back for progressive shortness of breath, chest pains and palpitations. Workup on the patient showed an enlarged heart, irregular heartbeat and signs of heart failure.
Both patients had one thing in common. Both were loud snorers, as reported by their wives. We sent the two patients for “sleep test” or polysomnography, which monitors the breathing pattern when one sleeps, including the airflow at the nose and mouth, as well as the movement of one’s chest and other respiratory muscles. These are correlated with the levels of oxygen and carbon dioxide in the blood.
‘Sleep test’ results
The results of the “sleep test” of both patients showed significant obstructive sleep apnea or OSA. Apnea means stopping of one’s breathing, and patients with OSA may have several episodes of complete cessation of airflow or stopping of breathing for at least 10 seconds each night when they sleep. Some may not completely stop breathing and instead have hypopnea, wherein airflow decreases by 50 percent for at least 10 seconds or decreases by 30 percent with an associated decrease in the oxygen saturation in the blood.
This is then reported as the apnea-hypopnea index (AHI), and depending on the frequency of their occurrence per hour, the OSA is described as mild, moderate or severe. Our two patients both had severe obstructive sleep apnea. And this was the likely culprit for the first patient’s uncontrolled high blood pressure and the second patient’s heart disease with progressive heart failure.
People who have OSA snore loudly, with their heavy snoring interrupted by several seconds of silence until the snoring resumes. They may also have gasping breaths from time to time. The intervals of silence actually happen during the time when the individual is apneic or he/she stops breathing. OSA patients usually wake up in the morning feeling tired and unrested despite a supposedly long sleep. They may doze off at work, even when someone is talking to them or while driving. This can lead to serious accidents on the road.
Other symptoms of OSA may include headaches, difficulty in concentrating, mood changes such as irritability and depression, forgetfulness, increased heart rate and/or blood pressure, decreased sex drive, unexplained weight gain and heavy night sweats.
OSA is also usually associated with heart diseases, hypertension, diabetes and the so-called metabolic syndrome, which is a clustering of cardiometabolic factors including overweight, increased waist circumference indicating visceral or internal obesity, hypertension, high blood sugar, high triglycerides and low high density lipoprotein (HDL) cholesterol, which is the “good cholesterol.”
Quality of sleep
In a study done by researchers at the University of Pittsburgh, 800 people between the ages of 45 and 74 were surveyed about the quality of their sleep; and three years later, the researchers found that the people who reported snoring loudly were more than twice as likely to have metabolic syndrome than quiet sleepers.
Individuals with OSA are rarely aware that they have this problem. Some of them even deny that they snore. The problem is recognized by others, usually the spouses or bed-partners, who see and hear the individual with OSA during episodes.
Symptoms of OSA may be present for years or even decades without identification, especially those who sleep alone. Many also have the wrong impression that snoring is a sign of deep restful sleep and find nothing seriously wrong with it, so they never report it to their doctors.
As the medical diagnosis implies, obstructive sleep apnea is actually caused by an obstruction of the airway during sleep. Generally, the muscle tone of the body relaxes during sleep. The airway at the throat is composed of walls of soft tissue and muscles; when these relax, they can collapse, obstructing one’s breathing.
A very minor degree of OSA—like a few short episodes of apnea when sleeping—can still be considered part of normal sleep. This may happen when one has nasal and throat congestion due to an upper respiratory tract infection. Transient spells of OSA may also occur due to some drugs (sedatives and tranquilizers) or alcohol. But when the episodes become longer and more frequent (equal to or more than five times every hour of sleep) and persistent, this type of OSA can complicate into something more serious later on.
(Next week: Complications and treatment of OSA)
