February was heart month, and this is another column in a series about the primary risk factors for heart disease. Sleep apnea refers to periodic absence of breathing during sleep. There are two types of sleep apnea:  obstructive and central.

Obstructive sleep apnea (OSA) is common in people who are overweight; have a thick neck; have a receding chin; or have other conditions that can obstruct airflow when upper airway tissues relax during sleep — including enlarged tonsils and adenoids in children. Typically, people with OSA snore. Often their bedpartner notices that they periodically stop breathing for a few seconds when sleeping. Often OSA sufferers awakens suddenly with a snort.

Central sleep apnea is common in people who live above 3,000 feet, and is more apt to occur as people age. At night the brain senses that there isn’t enough oxygen in the air, which triggers several deep breaths in a row. This results in a low blood carbon dioxide levels, which triggers breathing to stop for several seconds to allow CO2 to return to normal. Some people have mixed apnea — obstructive and central.

Apnea sufferers are in and out of a deep sleep all night long, unbeknownst to them, which wreaks havoc on their body, particularly the cardiovascular system. The classic symptoms of severe sleep apnea are failure to feel rested upon awakening in the morning, and severe sleepiness during the day–which can lead to accidents and poor job performance.

Sleep apnea causes the following health problems:  depression; atherosclerosis; heart attacks; strokes; high blood pressure; dementia; heart rhythm disturbances (e.g. atrial fibrillation); sudden death; erectile dysfunction; prediabetes/diabetes (due to stress hormones secreted at night); night sweats; and “thick blood” — a high red blood count (hematocrit and hemoglobin) due to the body trying to compensate for the low blood oxygen at night by making more red blood cells. Anyone with any of these problems should be screened for sleep apnea.

Sleep apnea can often be diagnosed from what a bedpartner notices. It can be confirmed with a simple, inexpensive overnight oximetry — wearing a finger monitor that measures pulse rate and oxygen level all night. If this test is normal, sleep apnea is unlikely. If it’s abnormal, the next step is a more extensive overnight sleep study. A home sleep study is more convenient and less expensive, but not as complete or accurate as a study done in a sleep lab such as the one at VVH. Furthermore, in a sleep lab a “split sleep study” can be done:  During the first half of the night, the diagnosis of sleep apnea is established, along with the type (obstructive, central, or mixed). If sleep apnea is confirmed, CPAP is applied and adjusted during the second half of the night.

If sleep apnea is diagnosed, a thyroid blood test should be done, because low thyroid can be a caouse. People with sleep apnea should avoid alcohol, sleep aids, and sleeping on their back—all of which make apnea worse. Losing weight helps in OSA sufferers who are overweight. In some cases, special dental appliances and throat surgery can help. In pure central apnea, moving to sea level usually helps. However, most people with sleep apnea need CPAP (continuous positive airway pressure). This involves wearing a mask (which usually just covers the nose) at night that is hooked up through tubing to a quiet machine that puts out air at a continuous pressure, thereby preventing the apneic spells.

Most people tolerate CPAP well, and start feeling better within a few days of starting it. People who tolerate it find they fall asleep faster, sleep more soundly, and feel more rested when they wake up in the morning and for the rest of the day. Problems such as hypertension and arrhythmias often improve or resolve.

It’s estimated that about 18 million Americans have obstructive sleep apnea, with over 90 percent of them undiagnosed. Many more people living at altitude suffer from central sleep apnea, and most of those are undiagnosed. If after reading the information above, you or your partner think you could have sleep apnea, it would improve your quality of life, and perhaps save your life, if you sought diagnosis and treatment. Your primary care provider should be able to help you with this. For difficult cases, we’re fortunate to have lung specialist Dr. Khilnani and his competent staff at The Lung Center at Valley View Hospital.

Dr. Greg Feinsinger is a retired family physician who started the non-profit Center For Prevention and Treatment of Disease Through Nutrition. For questions or to schedule a free consultation about nutrition or heart attack prevention contact him at gfmd41@gmail.com or 970-379-5718.