DEAR DR. ROACH: My husband is 75. I am 68. Our family doctor says that our blood pressure average is fine at 140/80 with no medicine. We thought it should be 120/70, but he says the limit is higher for seniors in order to decrease falls. This is pretty confusing. Do you think it’s OK?

— S.M.

ANSWER: The best goal for blood pressure has been the subject of controversy. For the overall population, a level of 120/80, slightly less than the average blood pressure in the U.S. and Canada, is associated with a lower risk of heart disease, stroke and death than a blood pressure of 140/80. But the difference is pretty small. A blood pressure of 160/90 has a significantly higher risk, and at blood pressures above 160 systolic (that’s the first or “top” number), the risk for stroke and heart disease rises steeply.

A recent trial (the SPRINT trial) showed that among older people with high blood pressure who had increased risk for heart attack, a systolic blood pressure goal of 120 was better at reducing risk than a blood pressure goal of 140. Both groups had a diastolic (the second or “bottom” number) goal of less than 90. However, the goal among people at lower risk is not as clear.

Most experts would not treat people with medication unless their average blood pressure is over 140 systolic or over 90 diastolic. In people treated with medication, some experts prefer a goal of less than 130/less than 90, while others would treat to less than 120/less than 90. It is true that more blood pressure medication and more intensive goals can lead to greater side effects, including falls. However, in the SPRINT trial, there was NO increase in fall risk and a 0.6 percent increase in the risk of fainting.

Nondrug therapy, which includes modest salt restriction, regular exercise and stress reduction, can lower the blood pressure enough that people do not need medication.

DEAR DR. ROACH: Can Lyme disease send a person into Parkinson’s disease? I tested positive for Lyme — I had the bulls-eye rash, fever and terrible headaches. After a month on doxycycline, my left arm started shaking and my neurologist diagnosed me with Parkinson’s. The doctor said it had nothing to do with the Lyme disease. What is your opinion?

— S.M.

ANSWER: I can absolutely understand why you might suspect that the neurologist could be wrong. The coincidence seems too much to believe. However, I think your neurologist is probably correct. The different types of neurological complications of Lyme disease are many and varied. The most common are any combination of meningitis symptoms (inflammation of the lining of the brain, with headache, fever, stiff neck and light sensitivity); disorders of the cranial nerves (especially the facial nerve, so people with neurological Lyme disease can look like they have Bell’s palsy); and damage to peripheral nerves, causing pain and weakness or numbness, often resembling sciatica (but may include other parts of the body).

A detailed neurological exam by a neurologist would look for signs of Parkinson’s disease — not just the tremor you describe, but also muscle rigidity and changes in gait. These would be very unusual in Lyme disease. I did find cases resembling some aspects of Parkinson’s disease, but they improved with treatment. It is possible that the stress of the Lyme disease hastened the onset of Parkinson’s disease you were destined to get.

I say your neurologist is “probably correct” because what I found — absence of data to support a correlation — does not mean that there is no correlation, and it is possible that time may prove Lyme disease is connected to Parkinson’s. However, I think it’s unlikely.

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Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.