April 2, 2010
Dear Mayo Clinic:
I have normal systolic blood pressure, but my diastolic goes between 82 and 96 during the work day and goes down to normal at night or when there is no stress. Should I be concerned or is this normal?
If you don't have other health issues that increase your risk of cardiovascular problems, the situation you describe — isolated diastolic hypertension — isn't dangerous now. But it's not normal, either. People with elevated diastolic blood pressure often develop elevated systolic blood pressure over time. You can help prevent that by taking steps to lower your diastolic blood pressure to a normal level.
A blood pressure reading, given in millimeters of mercury (mm Hg), has two numbers. The first, or upper, number measures the pressure in the arteries when the heart beats (systolic pressure). The second, or lower, number measures the pressure in the arteries between beats (diastolic pressure). Normal blood pressure is below 120/80 mm Hg.
Research regarding diastolic blood pressure has evolved considerably over the last several decades. During the 1970s and 1980s, many researchers and physicians believed the diastolic reading was the more important of the two blood pressure measurements. Now, we know they are both equally important.
Minimal elevations of diastolic blood pressure (less than 95 mm Hg) alone don't pose an immediate significant health risk. But that's assuming you're in good health otherwise and don't have any additional factors that put you at risk for cardiovascular problems. Those factors include diabetes, kidney disease, obesity, smoking, hardening of the arteries (atherosclerosis), or a history of heart disease or a heart attack.
If you don't have any additional risk factors, regularly monitoring your blood pressure and making lifestyle changes to decrease your diastolic blood pressure may be all that's necessary at this time. Taking steps to reduce your blood pressure to a normal level is important because an elevated diastolic pressure puts you at a higher-than-average risk of developing elevated systolic blood pressure as you age. Changes that can make a difference include eating a low-salt diet, avoiding alcohol, exercising regularly, not smoking and maintaining a healthy weight.
If you have other cardiovascular risk factors, any elevation in diastolic blood pressure — even if it's small — significantly increases your risk of cardiovascular problems. If that's the case for you, I strongly recommend you work with your physician to create a comprehensive treatment plan that addresses all your risk factors, including high blood pressure.
Effective management of high blood pressure is important because if left untreated it can have serious, long-term consequences. High blood pressure damages the lining of the blood vessels and accelerates hardening of the arteries throughout the body. This, in turn, can lead to a variety of health issues, such as cerebrovascular disease, heart attack and peripheral vascular disease, among others. These are cholesterol-related complications that people often think of when considering health problems associated with high blood pressure.
But there's another way high blood pressure is equally dangerous. The constant pounding of high blood pressure on blood vessels can also lead to serious health problems, including the type of stroke where there is bleeding in the area between the brain and the tissues that cover it (subarachnoid hemorrhage), congestive heart failure, kidney failure and abdominal aortic aneurysm.
In addition, increasing evidence suggests a correlation between high blood pressure and dementia. Research has shown that successful treatment of high blood pressure is associated with a reduced risk for dementia and Alzheimer's disease. So, to protect the brain, treat high blood pressure.
To effectively address your situation, I encourage you to make an appointment with your doctor to assess your elevated diastolic blood pressure and, based on your health history and other medical issues, develop a plan to manage it appropriately.
—John Graves, M.D., Nephrology and Hypertension, Mayo Clinic, Rochester, Minn.