Dr. Roach: A range of blood pressure readings can be telling

Keith Roach
To Your Health

Dear Dr. Roach: My doctor recently retired, my new one is very concerned about my systolic blood pressure, which was 150. I made quarterly visits to my old doctor, who never had a comment about my pressure numbers. My new doctor wants me on medication, and we agreed I would buy a home blood pressure machine to check my pressure.

I recorded it for 21 days, sometimes more than once day. My systolic numbers range from 118 to 150 and average 132. Out of 26 times, it was 150 once. My diastolic numbers are pretty consistent in the mid- to low 80s.

I sat still at my desk for these tests. Is seeing such a range a concern? I am 71 years old, 6 feet tall and weigh 170 pounds. I am very physically active.

— T.H.

Dear T.H.: Your average blood pressure is modestly elevated. The range of readings you are asking about is not unusual. Blood pressure always varies throughout the day, and it’s the average blood pressure doctors are most concerned about, unless there are very high spikes in the blood pressure, which you do not have.

Dr. Keith Roach

Different physicians take different approaches to modestly elevated blood pressure. Given that you are otherwise apparently at low risk (no diabetes, nor heart or vascular disease), I do not think there is a compelling reason to start medication therapy. Your experience does show how important it is to get many blood pressure readings: The reading of 150, had that been the only number your new doctor had, would have been a reason to start medication treatment.

You can help keep blood pressure down by eating a diet that is lower in salt, getting regular exercise and managing stress. A diet that is high in fruits, vegetables, legumes and nuts, and lower in processed foods than most North Americans get, reduces heart disease risk independent of blood pressure.

Dear Dr. Roach:You recently wrote a column on taking high blood pressure medications later in the evening, specifically near bedtime. It is my understanding that some people’s blood pressure will drop so low in this situation the perfusion pressure to the optic nerve will be insufficient. This can lead to glaucomalike atrophy of the nerve, potentially leading to loss of function.

If one is best served with late-evening high blood pressure medications, then it seems careful follow up to determine if loss of optic nerve is occurring should be recommended.

-- K.S.

Dear K.S.: You are correct that dropping the blood pressure too quickly can limit blood flow to the brain, and the retina is in fact brain tissue, with the same potential for injury. However, the medicines for high blood pressure in common use now do not suddenly drop blood pressure to the point where there is a risk of damage to the tissues. The brain has a very highly developed ability to maintain blood flow across a wide range of blood pressures.

Importantly, the trial that has provided evidence to nighttime blood pressure medicine showed a decrease in stroke risk by half. Although the optic nerve itself was not evaluated in the study, the better control of high blood pressure outweighs any potential risk of too-low blood pressure. Regular eye exams in a person with high blood pressure are recommended no matter when medication is taken.

Readers may email questions to ToYourGoodHealth@med.cornell.edu.