Q: My blood pressure is 150/70, so my systolic reading is high but my diastolic is normal. Is that still a health risk?
A: Absolutely. A high systolic blood pressure (the top number) is a significant health concern, independent of diastolic blood pressure (the lower number). When systolic blood pressure is 140 or higher, but diastolic blood pressure is less than 90, the condition is called isolated systolic hypertension (ISH). This is the most common type of hypertension in older people, due to arterial stiffness, which increases with age.
For years doctors were concerned mainly with high diastolic pressure. But research over the past two decades has linked ISH not only to coronary artery disease but also to strokes, diabetes, chronic kidney disease and dementia. One study, for example, found that people over 40 with ISH (but not those with isolated diastolic hypertension) were at increased risk of dying from cardiovascular disease, compared to those with normal blood pressure.
In 2003 the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure concluded that in people 50 and older, elevated systolic blood pressure (over 140) is an even stronger risk factor for cardiovascular disease than elevated diastolic blood pressure. Less is known about the health risks of ISH in younger people.
What to do: If you have ISH, it is important to treat it, as you would other forms of hypertension. Your health care provider should advise lifestyle modifications— dietary changes (including sodium reduction), exercise, weight loss and stopping smoking—and, if necessary, drug therapy.