Sleep Soundly for Heart Health
By Steven Georgeson, MD
If you're not getting a restful night's sleep, you may be causing damage to your heart. Undiagnosed sleep disorders can cause or worsen many cardiac conditions. Half of all patients with high blood pressure, atrial fibrillation and congestive heart failure and one third of patients with coronary artery disease suffer from obstructive sleep apnea, the most common sleep-related breathing disorder.
How does your sleeping pattern affect your heart? In general, sleep relaxes the cardiovascular system. Obstructive sleep apnea prevents that relaxation. It occurs when the upper airway is either partially or completely closed during sleep. This closure causes periods of stopped breathing which lowers the oxygen level of the blood and increases blood pressure and adrenaline levels.
By fragmenting sleep and by producing surges of adrenaline, individuals with obstructive sleep apnea are kept in a continually activated state. This activation prevents the normal decrease in nighttime blood pressure, increases the irritability of the heart's electrical system, causes ongoing inflammation and alters the pumping function of the heart.
People who are overweight and suffer from obstructive sleep apnea are at high risk for developing atrial fibrillation, the most common type of irregular heart rhythm. In addition, people with untreated obstructive sleep apnea have an increased risk for a second episode of atrial fibrillation after the heart is shocked to restore the normal heart rhythm.
Sleep disorders may also cause or worsen congestive heart failure by a variety of mechanisms. Obstructive sleep apnea will increase the pressure and stress in the heart, making it harder to pump blood to the body. By restricting oxygen intake, it also impairs the heart's pumping ability.
The majority of patients with obstructive sleep apnea remain undiagnosed. Many either have no symptoms or do not recognize the symptoms related to their sleep disorder until they are treated for heart disease. Symptoms include snoring, daytime sleepiness and recurrent episodes of waking suddenly or gasping upon waking. While many people associate sleep apnea with obese middle-aged men, one third of people with the disorder are women and many are not obese.
Obstructive sleep apnea may be an underlying cause of heart disease in people who are obese with difficult-to-control blood pressure, congestive heart failure or multiple episodes of atrial fibrillation and in individuals with high blood pressure who cannot control it with multiple medications.
If you suspect that you may have a sleep disorder, talk to your doctor. A sleep study may be recommended to determine the cause of your sleep disturbance. A sleep study requires an overnight stay at a sleep lab for monitoring of the blood oxygen level, the heart rate, the stage of sleep, jaw muscle tone, sleep position and chest and stomach wall movements.
If you are diagnosed with a sleep disorder, a variety of treatments are available to improve your heart condition and quality of life, including weight loss, oral appliances, medications, surgery and the use of a continuous positive airway pressure (CPAP) machine, which helps keep the airway open during sleep by applying air pressure through a mask. The CPAP machine helps eliminates apneas, keeps sleep from being fragmented and corrects the adverse effects on the body seen in people with obstructive sleep apnea. It can also improve vitality, physical functioning, social functioning and general health perception. This treatment improves the mechanics of the heart, reduces symptoms in patients with heart failure, increases the pumping function of the heart and lowers both nighttime and daytime blood pressure. As a result, the number of blood pressure medications or the dosage of medication can often be reduced.
Dr. Georgeson is chief of cardiology services at Robert Wood Johnson University Hospital Somerset.