Dear Doctors: I'm a 97-year-old woman. Sometimes my blood pressure drops, and I faint. It lasts just a few seconds, because as soon as I'm prone, I wake up. I don't have any cardiac issues, and there's no pain. It's just a sudden funny feeling, then I'm out. What might be causing this?
Dear Reader: Each time the heart beats, it sends a surge of freshly oxygenated blood into the closed loop of the circulatory system. The result is a sustained force against the walls of the arteries, veins and capillaries, which we refer to as “blood pressure.” It allows blood to move continuously through the circulatory system, which is largely passive, and makes possible the delivery of oxygen and nutrients to tissues and cells throughout the body.
When we think about how blood pressure can adversely affect health, the focus is primarily on hypertension. That refers to blood pressure that is higher than normal. Having high blood pressure increases someone's risk of developing heart disease and of having a stroke. Each of these is a leading cause of death in the U.S.
But having blood pressure that is lower than normal, which is known as hypotension, can have a negative impact on health, as well. When blood pressure drops too far, the tissues of the body begin to develop a deficit of oxygen. This can cause symptoms that range from mild to severe. A substantial or sustained drop in blood pressure can be life-threatening.
Readings of less than 90/60 mm Hg are considered hypotension. But how far blood pressure can drop before someone begins to feel the effects varies from person to person. Symptoms include feeling light-headed or dizzy, headache, confusion, fatigue, nausea, having episodes of blurred or altered vision, pain in the neck or back, changes to heartbeat and fainting. It's possible that you are experiencing one or more of these and not associating them with low blood pressure.
Hypotension can arise from a wide variety of causes. These include dehydration, infection, exhaustion, nerve damage from diabetes, the effects of alcohol, abnormal heart rhythms, heart disease and certain heart conditions. Sudden changes in position, such as from sitting to standing, can cause a drop in blood pressure. So can certain medications, including those used to manage heart failure and hypertension.
Treatment may entail a change of medication, changes to hydration or diet, or treatment to address cardiac issues. Compression stockings, which help blood stay in the upper body, can also be helpful.
Because your episodes of hypotension lead to fainting, it's important to seek prompt medical attention. Fainting is dangerous for anyone, but the risk of fracture or head injury is greater in older adults.
Begin with your primary care provider. It is likely they will conduct a thorough physical exam, review your recent medical history and evaluate your diet and any medications you are taking. You may also be referred to a cardiologist for a more detailed evaluation. If this is the case, we urge you to follow through with the recommendation.
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