Sleep & Heart Disease
While some aspects of the relationship have not been clarified, there is definitely a direct correlation between sleep, sleep disorders, and heart disease. Any time you wake up from sleep, even if it is momentary, your heart rate and blood pressure climb, forcing your heart to exert more energy. Professionals believe that it is this extra workload that causes an increased risk of sudden cardiac death just after awakening. Research studies routinely suggest that sleep, disordered breathing cause high blood pressure, as well as increased risk of heart disease and stroke.
Obstructive Sleep Apnea has been proven to lead directly to high blood pressure. The repeated episodes of ceased or shallow breathing cause a drop in oxygen, and the brain is aroused over and over again. As previously mentioned, every time a person is awakened, the heart is forced to pump harder. The combination of continuous loss of oxygen and increased heart rate and blood pressure can eventually lead to a permanent increase in blood pressure.
Congestive Heart Failure (CHF)
Sleep, related breathing disorders can be both the cause and the effect of CHF. There arc studies that show that OSA is a significant risk factor for the development of heart failure. Also, about 40% of the people who have CHF also have what is known as Central Sleep Apnea (CSA). This type of irregular breathing also causes drops in oxygen levels and constant arousals throughout the night. The extra workload worsens the CHF, causing a vicious cycle to begin. Treatment of the CSA will improve heart function as we as sleep quality.
Hypertension is the leading cause of stroke, and as mentioned above, it is directly linked with OSA Also, strokes occur when oxygen is reduced or cut-off to the brain, so it is believed that OSA may directly lead to this. Other affects from OSA, such as excessive sleepiness may interfere with a person's recovery after a stroke.