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.)

Dear Doctor: When I was growing up, I saw my doctor annually for a physical exam. So I was surprised when my daughter told me that her physician doesn't believe in them. Do you agree? If not, what should a physical exam include?

Dear Reader: Although there's a trend toward doing away with an annual checkup for healthy adults, both of us believe in and support the practice of a yearly physical exam. It's covered by most insurance policies and, at the very least, is an opportunity to reconnect with your primary care physician. When the annual exam becomes more than just an exercise in gathering data, it's an extremely useful tool for both the physician and the patient.

What exactly does a yearly exam consist of? That depends on each physician. Considering that the annual checkup has been one of the cornerstones of primary care, it's a bit of a surprise to note that there are no guidelines or consensus statements regarding what the visit should entail. We can't speak for other physicians here, but can instead explain what we do in our practices, and why.

In addition to performing a head-to-toe exam, we approach the annual exam as a chance to help our patients take stock. We review the previous year and plan for the future. We go over any active problems the patient may have, and evaluate how a treatment plan is (or isn't) working. We review any medications the patient is taking, with an eye to either renewing, changing or eliminating them. We update family medical histories to pinpoint any potential hereditary risk factors, such as certain cancers, coronary artery disease or Alzheimer's disease.

We believe that the results of these discussions, as well as the information gleaned from the screening and diagnostic tests, help patients obtain a clear picture of their physical health. They also offer patients an opportunity to set goals and play an active role in their health care. The lab tests and screenings that we recommend can not only reveal potential problems, but also provide an important baseline against which any future changes or anomalies can be evaluated.

Specifically, we review blood pressure, heart rate, weight and body mass index. For labs, we order a complete blood count, kidney, liver and thyroid function tests, diabetes and cholesterol screenings, and a check of vitamin D levels. For women, we recommend age-appropriate screening with mammogram, Pap smear and bone density test. With men, we discuss the risks and benefits of the PSA test, which screens for prostate cancer. For patients over 50, we recommend colon cancer screening with a colonoscopy. We review and advise vaccines.

The argument against an annual physical is that, for healthy adults, the tests are unnecessary. However, we believe that our approach yields a multidimensional picture of a person's health journey. It makes it more likely we will catch certain conditions early, when they are easier and less costly to cure. In our opinion, the annual physical exam empowers our patients and paves the way to better health.

(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.)