Health Risks

In the past several years, medical research has shown a strong relationship between sleep-disordered breathing (SDB) and cardiovascular disease (CVD). Results from the Sleep Heart Health Study (an ongoing, multi-center study funded by the National Institutes of Health) have shown an association between SDB and high blood pressure (hypertension), congestive heart failure (CHF), and stroke. In addition, results from the Wisconsin Cohort Study have shown that people with SDB are more likely to develop high blood pressure.

The apneas and hypopneas associated with SDB decrease oxygen levels and increase carbon dioxide levels in your blood. As these levels become more extreme, you begin to struggle for air—in essence suffocating—which causes you to wake up briefly and start breathing again. During each apnea, the stress on your body leads to increased or irregular heart rate and increased blood pressure. According to recent medical research, the stress caused by SDB increases your risk for developing high blood pressure, cardiac arrhythmias, and heart failure.

Additionally, recent studies show that treating SDB can decrease blood pressure and have positive effects on the heart.

SDB and High Blood Pressure (Hypertension)

People with untreated SDB are more likely to develop hypertension. More significantly, there is what doctors call a "dose-response relationship": the more severe the SDB, the greater the risk of developing hypertension.

During healthy sleep, your blood pressure decreases. However, when you are not treating your SDB, you probably experience elevated blood pressure during sleep. Instead of getting a restful night's sleep, you put your heart through a night of stress. This nightly stress leads to increased blood pressure that affects you both night and day. CPAP has been shown to significantly decrease blood pressure in SDB patients, and these decreases can be seen during both sleep and wakefulness.

People who take more than two drugs for their high blood pressure (called "drug-resistant hypertension") are even more likely to have SDB. About 83% of people with drug-resistant hypertension have SDB. For this group of patients, positive airway pressure (PAP) therapy may be especially important.

SDB and Congestive Heart Failure (CHF)

Perhaps because of the nightly stress on the heart, people with untreated SDB are more likely to develop heart disease, especially congestive heart failure (CHF). With CHF, the heart is not able to circulate blood effectively. Symptoms include weakness, shortness of breath, edema (fluid retention), enlarged and tender liver, and swollen neck veins.

Approximately 50% of people with CHF have SDB. Treating SDB in CHF patients has definite benefits. PAP therapy improves the heart's ability to do its job and improves the overall health and well-being of the patient.

SDB and Diabetes

People with diabetes often have sleep-disordered breathing (SDB), and while both diseases increase a person's risk of heart disease, the combination of the two puts people at an even higher risk. The combination of these diseases is very common. In fact up to 65% of people with type 2 diabetes have SDB.

Diabetes has become a leading concern for public health professionals in the United States. It affects over 18 million Americans and has become the fourth leading cause of death by disease. It also increases a person's risk for developing heart disease, another leading cause of death. While medical researchers understand how diabetes works in the body and the health risks it presents, they still haven't discovered the exact causes.

Diabetes interferes with and may eventually destroy the body's ability to produce and properly use insulin, the hormone that allows the body to use glucose. Glucose is the "fuel" that our bodies need for energy, and when our bodies stop making or using glucose, they begin to shut down-like a car running out of gasoline.

Doctors usually diagnose diabetes with a blood test and treat diabetic patients with oral medications and insulin injections. Costs for diabetes treatment in the US during 2002 totaled $132 billion. With obesity on the rise in the US, the number of diabetics and the costs associated with their treatment will also increase.

Studies over the last two years suggest that SDB may play a role in causing diabetes to develop. The first study, which was published in 2002 in the American Journal of Epidemiology, showed that people who snore regularly are more likely to develop diabetes. This study was part of the Nurses Health Study, and there were over 16,000 participants. In 2003, a study with 1,400 participants showed that SDB increased one's risk for developing diabetes. Both of these studies illustrate the importance of treating SDB as a way of reducing additional health risks.

New data presented at a scientific meeting in 2003 suggest that treating SDB may also help to improve blood glucose control. Although the study examined only a small number of SDB patients, the CPAP users experienced a significant fall in blood glucoses levels after meals.

Multiple studies have already shown that effective treatment of SDB reduces blood pressure both day and night. This finding is important because SDB increases a person's risk of developing high blood pressure, and high blood pressure is common in people with diabetes.

SDB and Stroke

Up to 70% of those who have had a stroke also have SDB. And many researchers believe that untreated SDB may increase your risk of having a stroke. As with hypertension and CHF, the type of stress that SDB puts on your body may lead to a stroke.

Stroke patients with untreated SDB have a significant disadvantage in the struggle to recover from stroke. They have difficulties concentrating and performing activities of daily living. Recovering from a stroke takes incredible energy and motivation. The excessive daytime sleepiness and fatigue caused by untreated SDB may make it more difficult for a patient to participate in rehabilitation programs, resulting in poor recovery. In fact, untreated SDB in stroke patients increases one's risk of dying in the first year after the stroke. It also limits their ability to recover all their pre-stroke abilities.

The National Stroke Association recommends that all acute stroke facilities and stroke rehabilitation programs screen for SDB. Recognizing SDB in stroke survivors is often challenging because the symptoms associated with SDB are often attributed to stroke. Obtaining a complete sleep history from family members will help determine whether SDB was present prior to the stroke or developed after the stroke. Well-educated medical professionals, nursing staff, and other healthcare providers have the best chance of recognizing SDB in stroke patients.

Dangers of Sleepiness

More and more Americans report feeling sleep deprived. Americans surveyed by the National Sleep Foundation report receiving an average of only 6.5 hours of sleep per night—that's 1.5 hours below the average person's needs. The National Sleep Foundation also reports that every year at least 100,000 automobile accidents occur because a sleepy driver gets behind the wheel. Approximately 71,000 injuries and 1,500 deaths result from these easily avoided accidents.

Two new studies indicate that drivers with OSA have a much greater chance of being involved in a traffic accident. One study found that people with OSA are six times more likely to be involved in a traffic accident. Another study found that people with OSA are 15 times more likely to be involved in a traffic accident.

These numbers provide a dramatic illustration of the importance of sleep. Some activists have even begun to compare driving sleepy to driving drunk. Studies show that reaction times of sleepy drivers are as bad as or worse than drivers with blood alcohol levels of 0.08%, which is the legal limit in some parts of the United States. Most people won't drive drunk, but they don't think twice about driving when sleepy.

For sleepy drivers, even more so than drunk drivers, there is a sense that "it can't happen to me." Unfortunately, it can. It happens because our bodies begin to take "microsleeps" when we deprive them of rest for too long. You may have already taken a few microsleeps at the wheel without knowing it. In the early stages of sleep deprivation, they last only a few seconds, but that's long enough to cause an accident.