High Blood Pressure is a leading cause of stroke and heart attacks. Recently, we have come to understand the relationship of Sleep Apnea (stopping breathing while asleep) to elevations in blood pressure. In a recent study they found that 60% of patients with high blood pressure, being treated with three or more medications, still experiencing persistent elevations had undiagnosed Sleep Apnea. Normally, during sleep, blood pressure drops by 10 to 15 points. However, obstructed breathing at night causes low oxygen levels and repetitive arousals from sleep. As a result, the part of the nervous system called the sympathetic nervous system overreacts. The sympathetic nervous system constricts blood vessels, which raises blood pressure. Unfortunately, after a few years, these changes become chronic and persist during the day. As a result, many people with Sleep Apnea develop high blood pressure. Fortunately after treatment for Sleep Apnea, substantial drops in blood pressure occur and the associated risk of heart attack and stroke decrease. Taking care of Sleep Apnea can prevent and possibly cure High Blood Pressure.
Recent studies have shown that there is a major increase in the incidence of stroke in those who have Sleep Apnea. In fact, the risk of stroke is increased to three times normal. A recent study done on those with Transient Ischemic Attacks (TIA) revealed that over 60% of those patients had Sleep Apnea. In an accompanying editorial, a leading neurologist stated that all patients with strokes should be screened for Sleep Apnea.
One may wonder, why the increased incidence of Sleep Apnea in stroke victims? First of all, during the episodes of Apnea (stopping breathing) there is a major decrease in blood flow to the brain. There is also an accompanying increase in pressure in the brain, further inhibiting blood flow. Also, blood tends to clot more easily in those with Sleep Apnea. Most victims develop high blood pressure and damage to the lining of the blood vessels. This further predisposes them to the occurrence of strokes. Finally, and most importantly, the brain loses its ability to control its own blood flow. This is called cerebral autoregulation and is very important in preventing strokes. If you or a loved one has had a stroke or TIA it is important to make sure that you do not have Sleep Apnea.