Doctor K: Reducing upper blood pressure number helps

DEAR DOCTOR K: I’m 71 years old. My systolic blood pressure is usually in the 150s to 160s, which is high. But my diastolic blood pressure is usually in the 70s, which is normal. Do I need treatment?

DEAR READER: A blood pressure measurement includes two numbers: systolic pressure (the upper number) and diastolic pressure (the lower number). These numbers are measured in millimeters of mercury, or mmHg.

Your systolic pressure is high: 140 mmHg or over is high. And your lower number is normal: normal diastolic pressure is below 80 mmHg. When your systolic blood pressure is high and your diastolic blood pressure is low, it’s called isolated systolic hypertension (ISH). People with ISH do benefit from treatment, as it lowers the risk of heart disease and stroke.

Are you currently being treated for high blood pressure (hypertension)? If not, your doctor might start with lifestyle changes. Regular exercise, weight loss and cutting down on salt in your diet might fix the problem without medication.

If lifestyle changes aren’t enough, you’ll likely need medication. Because of your age, your doctor will probably aim to first gently lower your systolic pressure to below 150 mmHg. If you don’t have any bothersome symptoms, such as lightheadedness, your doctor will push to get your systolic pressure below 140 mmHg. Such treatment is also likely to lower your diastolic pressure, but the focus should be on your systolic pressure.

I was taught three things in medical school: (1) all that really mattered was the diastolic pressure; (2) older people had naturally higher pressures, so they didn’t need treatment; and (3) when you treated older patients, it caused symptoms such as lightheadedness.

Research since I was a medical student has shown conclusively that (1) and (2) are wrong. In fact, they were backward. Systolic pressure matters more than diastolic pressure, and older people clearly benefit from treatment. People like you with just a high systolic pressure are at higher risk for having a heart attack, heart failure or a stroke if you don’t get treatment.