Dear Doctor: I know that high blood pressure increases the risk of heart disease, stroke and more. However, is it still considered a risk factor if it's controlled with medicine?

Dear Reader: High blood pressure is a significant risk factor for heart attacks and strokes because it damages the arteries that supply the heart and the brain, causing them to narrow. Additionally, the heart has to work harder to deal with the resulting elevated blood pressure, increasing the risk of eventual heart failure. There is no disputing these facts.

As for whether someone with high blood pressure controlled by medication has a risk equivalent to somebody without high blood pressure, that's a good question -- and no studies have specifically tried to answer it. But researchers have studied patients with high blood pressure and the attempts to bring the blood pressure to different levels.

A 2015 breakthrough study in the New England Journal of Medicine took 9,361 patients with systolic blood pressure greater than 130 and randomly assigned them to either treatment to keep the blood pressure between 130 and 140 or more aggressive treatment to bring the blood pressure down to 120. The aggressively treated group got their blood pressure down to 121 on average, while the less aggressively treated group had an average systolic blood pressure of 136. The study was stopped after three years because of a 27 percent decrease in the overall death rate in the aggressively treated group.

A 2016 study in The Lancet combined data from 123 studies of hypertension treatment with a total of 613,815 patients. This analysis showed that for every 10-point decrease in blood pressure, the death rate decreased by 13 percent, the stroke rate decreased by 27 percent and the heart failure rate decreased by 28 percent. Like the former study, the benefits were greater with blood pressure below 130.

Lastly, an analysis of 16 studies published in 2016 in the Journal of Hypertension looked at the benefits of more aggressive treatment versus less aggressive treatment of blood pressure. The authors found a 16 percent decrease in death rate with blood pressure below 130 versus blood pressure greater than 130.

Although these studies don't directly answer your question, consider the incremental benefits of lowering your blood pressure. If, on medication, your systolic blood pressure is in the 130s, I would say that you're at greater risk than someone who is not taking medication and who has a blood pressure of 120. If you're on medication and your blood pressure is 120, it's hard to say how that compares to somebody who has a blood pressure of 120 and is not on medication.

The most important lesson is that if you have high blood pressure, you should treat it.

Also, a message for my readers: A recent column on whether to give aspirin for a heart attack in progress referred to two studies in which users received aspirin at various times. In referring to one study, the article stated that earlier users received aspirin an average of 1.6 hours before the onset of symptoms. Obviously, this should have said "after the onset of symptoms."

In referring to the other study, the article stated that patients received aspirin at least 24 hours after the beginning of symptoms. This should have said "up to 24 hours after the beginning of symptoms."

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: News reports are saying that researchers have figured out how stress causes a heart attack, and that it all starts in the brain. I quit smoking, I exercise and I've switched to a healthy diet. But how am I going to control my brain?

Dear Reader: The physical connection between the mind and the heart is something that, even in the absence of scientific data, humans have long intuited. Just take a look at our language. Feelings and events can be heartbreaking, heart-stopping and heart-rending. The guy everyone's crushing on is a heartthrob. When it doesn't work out, your heart aches.

Now a paper published in The Lancet offers scientific proof of what everyone from Shakespeare to Beyonce has been saying all along -- emotional stress directly affects the heart.

Drawing from two studies, researchers found that when people had high levels of activity in the amygdala, which is the region of the brain that telegraphs emotions like fear, stress and dread, they were more likely to develop heart disease. Participants with a hyperactive amygdala had more inflammation in their arteries, and the region of their bone marrow that creates red blood cells was more active.

Cardiovascular disease is the leading cause of death among adults, not only in the United States, but in the world. In 2013, one-third of recorded deaths in the U.S. were due to cardiovascular disease. All of which makes managing the mind-heart connection even more vital.

But how? You can begin right now by taking a slow, deep breath. If that felt pretty good, try it again. Now, let's talk about stress-reduction techniques.

Fortunately, with the advent of wellness programs in many workplaces, stress management is now taken seriously. Instruction begins with the basics -- no smoking, limit caffeine, drink less alcohol, cut down on screen time, get more sleep, take time to exercise and eat a balanced diet. If you recognize any of your own behaviors in that list, consider making a change.

Thanks to the mainstreaming of practices like meditation, tai chi and yoga, all of which have been proven to measurably reduce stress when practiced regularly, groups and classes are available practically everywhere. Whether it's at your gym, a community center, a senior citizens center or even on YouTube, there's a class that's right for you. When it comes to exercise, don't forget about oldies but goodies like a brisk walk or a gentle jog. You'll burn off some steam, work up some endorphins and quite likely feel refreshed.

And don't forget about fun. In a task-oriented world that has become fixated on success and results, doing something for the simple enjoyment of it has somehow fallen out of favor. In the same vein, reaching out to friends and family -- in person, not via text or Facebook -- can help you feel less stressed. Research shows that isolation is as toxic as some diseases, and the therapy can be as simple as a "hello."

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I was informed several years ago that carbonated drinks weaken bones, leaching the calcium from them. Is this true? What would be considered an acceptable amount for a teenager or a woman past menopause? Would carbonated spring water be better?

Dear Reader: Sodas are ubiquitous in our society. Even schools sell them. Further, both parents and children often use sodas as their primary source of liquids, shunning simple water -- the essence of life. The evidence between soda intake and obesity risk is irrefutable. Now let's look at the evidence on bone density.

Almost 20 years ago, a study published in the Journal of Bone and Mineral Research found that cola-drinking rats had lower levels of calcium, higher levels of phosphorus, lower levels of vitamin D and higher levels of parathyroid hormone than water-drinking rats. They also had lower bone density in the femur (hip) bone.

A 2006 study published in the American Journal of Clinical Nutrition assessed the amount of cola and non-cola carbonated beverages, both with and without sugar, consumed by 1,125 men and 1,413 women. The study followed participants for 25 years and then checked their bone mineral densities. The authors did not find an association between non-cola carbonated beverages and lower bone mineral density in either men or women. Nor did they find an association between cola consumption and lower bone density in men. However, women who drank cola sodas had significantly lower bone mineral density than those who didn't drink sodas, regardless of whether the sodas contained sugar or artificial sweeteners.

Another American Journal of Clinical Nutrition study published in 2014 followed more than 73,000 women between the ages of 30 and 55 for 30 years. At the end of the study, they found that the rate of hip fracture was 10 percent greater among women who drank more than 10 sodas (of all types) per week, compared to those who did not drink any sodas.

The authors then compared women with the same body mass index who drank soda versus those who didn't. Here the authors found a significant correlation between soda intake and hip fractures. Women who drank five to 10 sodas per week had a 16 percent increased risk of hip fractures, and women who drank more than 10 sodas per week had a 42 percent increased risk of hip fractures. The increased rates of hip fracture were seen in both caffeinated and non-caffeinated sodas, as well as colas and non-colas.

Carbonated spring water is simply water with dissolved carbon dioxide gas, but that's not to say it isn't acidic. The pH level is between 3 and 4 -- higher than sodas' roughly 2.5 pH -- while water has a pH of 7. The acidity could potentially pose a problem, but a study published in the British Medical Journal in 2005 found no difference in markers for bone turnover between postmenopausal women who drank carbonated mineral water for eight weeks and postmenopausal women who drank plain mineral water.

My advice is: Make plain water your primary source of fluid. Also, and this is important: Minimize the amount of sodas that you and your teenager drink. In addition to their link to obesity, they do seem to increase the risk of low bone density and bone fractures.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)