Is having a high top number (systolic) blood pressure, but a normal bottom number (diastolic) cause for concern?

Answers from Sheldon G. Sheps, M.D.

Yes. If you have a diastolic number — the bottom number of a blood pressure measurement — less than 90 millimeters of mercury (mm Hg) and a systolic number — the top number of a blood pressure measurement — greater than 140 mm Hg, you have a common type of high blood pressure called isolated systolic hypertension.

Isolated systolic hypertension can be caused by underlying conditions such as artery stiffness, heart valve problems or an overactive thyroid (hyperthyroidism).

For years, doctors focused primarily on diastolic blood pressure. The theory was that the body could tolerate occasional increases in systolic blood pressure, but consistently high diastolic pressure could lead to health problems. However, doctors now know that high systolic pressure is as important as high diastolic pressure — and even more important in people older than age 50.

The recommended goal for systolic pressure for younger people is less than 140 mm Hg. For people who are 60 or older, the recommended treatment goal is less than 150 mm Hg.

In people with isolated systolic hypertension, treatment may lower diastolic pressure too much, potentially increasing the risk of a heart attack or stroke. So if you have isolated systolic hypertension, your doctor may recommend that your diastolic pressure not be reduced to less than 70 mm Hg in trying to reach your target systolic pressure.

Isolated systolic hypertension can lead to serious health problems, such as:

  • Stroke
  • Heart disease
  • Chronic kidney disease
May. 16, 2014 See more Expert Answers