High blood pressure is another concern with sleep apnea patients. Incidence of high blood pressure has been reported to be 30 to 80% in patients with OSA.1,2
Normally there is a high level of oxygen (fuel for the body) and a low level of carbon dioxide (waste product of metabolism) in the blood. When a person has apnea (lapses in breathing) or hypopnea (reduced amount of air breathed due to severe narrowing of the airway), the amount of oxygen in the blood drops significantly. At the same time the amount of carbon dioxide in the blood rises above acceptable levels.
These abnormal fluctuations in oxygen/carbon dioxide levels can happen hundreds of times during the night. When the body senses these abnormal changes, which mean that toxic gas — low in oxygen and high in carbon dioxide — is being breathed, it protects itself by shrinking the blood vessels in the lungs. This, in turn, means the heart has to pump much harder to force the blood through the tiny constricted vessels. The heart also has to work harder to pump blood to the entire body. The body’s response to these low oxygen/high carbon dioxide levels — coupled with sleep fragmentation — predisposes people with sleep apnea to high blood pressure and the problems associated with it.
Those with existing heart problems may also experience palpitations at night when the oxygen level is low. Every cell in the body requires oxygen, especially the brain. If oxygen supply to the brain is diminished on a chronic basis, it may increase the risk for stroke.