Q. You have repeatedly criticized health care workers for making mistakes when measuring blood pressure. No one has answered my question of why a “proper” blood pressure reading requires me to assume a state that I exist in perhaps 1% of the time during an average day. That is, sitting in a chair, feet flat on the floor, arm level with my heart on an armrest, empty bladder and perfectly quiet for five minutes.

If I wanted to know what my blood pressure is 99% of the time during a typical day, it should be measured while in that typical state. That is walking, talking, typing, etc. I don’t understand why you are so stubborn about the blood pressure measuring technique.

A. You make a very good point. Blood pressure varies dramatically throughout the day. Stress, physical activity, driving, reading or watching television can all impact BP readings. Which number is the “actual” blood pressure?

The answer is that no one reading reflects your typical blood pressure. To get that, you would need a portable device that you would wear continuously for a day or two. This “ambulatory blood pressure monitor” would automatically test your pressure every 15 to 30 minutes throughout the day and every 30 to 60 minutes while you are sleeping. Your doctor could then tell your average BP over time.

Such testing is impractical for most people. That’s why the American Heart Association has published the BP measurement guidelines we have described. Standardizing this process in a clinic or doctor’s office is more likely to eliminate unreliable readings.

To learn more about proper technique and why we think measuring your own BP at home makes sense, you may wish to read our “eGuide to Blood Pressure Solutions.” This online resource is available under the Health eGuides tab at www.peoplesPharmacy.com.

Q. Can you recommend a way to remove dust mites? I recently developed a stuffy nose at night. The only thing I can think of is dust mites. I read about this in your column.

A. Nighttime nasal congestion can be caused by many things. An allergist might be able to help you identify the true trigger(s).

You are right, though, that dust mites are a common culprit. They thrive in mattresses, blankets, pillows, furniture and carpets. Their droppings cause allergic reactions. The best way to make life difficult for these microscopic organisms is to lower the humidity in the environment. They have a hard time surviving if it is below 50%.

Wash your bedding (pillowcases, sheets, mattress covers and blankets) regularly in hot water. We also find that bedroom air purifiers can be helpful. We personally like AirDoctor with three levels of filtration.

Q. I have been suffering from terrible acid reflux when I lie down to go to sleep. No doctor has been able to figure out why.

Then I read that my zolpidem sleeping pill could cause this problem. I stopped and the heartburn has greatly diminished after only one week. If I hadn’t read about this drug side effect, I would probably still be suffering.

A. The official prescribing information lists “dyspepsia” (indigestion) as a side effect of zolpidem (Ambien). One theory is that this medication relaxes the sphincter that separates the esophagus from the stomach. This could allow stomach contents to splash back up into the food tube, causing the symptoms you describe. We’re glad you are feeling better.

In their column, Joe and Teresa Graedon answer letters from readers. Write to them in care of King Features, 300 W. 57th Street, 41st Floor, New York, NY 10019, or email them via their website: www.PeoplesPharmacy.com. Their newest book is “Top Screwups Doctors Make and How to Avoid Them.”